defmodule Nx.BinaryBackend do
@moduledoc """
An opaque backend written in pure Elixir that stores
the data in Elixir's binaries.
This is the default backend used by the `Nx` module.
The backend itself (and its data) is private and must
not be accessed directly.
"""
use Complex.Kernel
@behaviour Nx.Backend
@doc false
defstruct [:state]
alias Nx.Tensor, as: T
alias Nx.BinaryBackend, as: B
import Nx.Shared
import Bitwise, only: [>>>: 2, &&&: 2]
@impl true
def init(opts) do
if opts != [] do
raise ArgumentError, "Nx.BinaryBackend accepts no options"
end
opts
end
## Creation
@impl true
def constant(%{type: type, shape: shape} = out, constant, _backend_options) do
data = :binary.copy(number_to_binary(constant, type), Nx.size(shape))
from_binary(out, data)
end
@impl true
def random_uniform(%{type: type, shape: shape} = out, min, max, _backend_options) do
min = scalar_to_number(min)
max = scalar_to_number(max)
gen_float = fn -> (max - min) * :rand.uniform() + min end
gen =
case type do
{:s, _} -> fn -> min + :rand.uniform(max - min) - 1 end
{:u, _} -> fn -> min + :rand.uniform(max - min) - 1 end
{:c, _} -> fn -> Complex.new(gen_float.(), gen_float.()) end
{_, _} -> gen_float
end
data = for _ <- 1..Nx.size(shape), into: "", do: number_to_binary(gen.(), type)
from_binary(out, data)
end
@impl true
def random_normal(%{type: type, shape: shape} = out, mu, sigma, _backend_options) do
mu = scalar_to_number(mu)
sigma = scalar_to_number(sigma)
variance = sigma * sigma
gen =
case type do
{:c, _} ->
fn ->
Complex.new(:rand.normal(mu, variance), :rand.normal(mu, variance))
end
_ ->
fn -> :rand.normal(mu, variance) end
end
data =
for _ <- 1..Nx.size(shape),
into: "",
do: number_to_binary(gen.(), type)
from_binary(out, data)
end
@impl true
def iota(%{shape: {}, type: type} = out, nil, _backend_options) do
from_binary(out, number_to_binary(0, type))
end
def iota(%{shape: shape, type: type} = out, nil, backend_options) do
t = iota(%T{type: type, shape: {Nx.size(shape)}, names: [nil]}, 0, backend_options)
%{out | data: t.data}
end
def iota(%{shape: {n}, type: type} = out, 0, _backend_options) do
data = for i <- 0..(n - 1), do: number_to_binary(i, type)
from_binary(out, data)
end
def iota(%{shape: shape, type: type} = out, axis, _backend_options) do
{dims_before, [dim | dims_after]} =
shape
|> Tuple.to_list()
|> Enum.split(axis)
# Number of repetitions of an index in memory
repeat_blocks =
dims_after
|> Enum.reduce(1, &*/2)
# Number of cycles of the counting pattern
cycles =
dims_before
|> Enum.reduce(1, &*/2)
data =
for _ <- 1..cycles,
i <- 0..(dim - 1),
_ <- 1..repeat_blocks,
into: "",
do: number_to_binary(i, type)
from_binary(out, data)
end
@impl true
def eye(%{shape: shape, type: type} = out, _backend_options) do
one = number_to_binary(1, type)
zero = number_to_binary(0, type)
shape_size = tuple_size(shape)
m = elem(shape, shape_size - 2)
n = elem(shape, shape_size - 1)
count =
shape
|> Tuple.delete_at(shape_size - 1)
|> Tuple.delete_at(shape_size - 2)
|> Tuple.product()
data =
for _ <- 1..count, i <- 1..m, j <- 1..n, into: <<>> do
if i == j, do: one, else: zero
end
from_binary(out, data)
end
## Conversions
@impl true
def from_binary(t, binary, _backend_options), do: from_binary(t, binary)
if Application.compile_env(:nx, :verify_binary_size) do
defp from_binary(%{type: {_, bitsize}, shape: shape} = t, binary) when is_binary(binary) do
actual = byte_size(binary)
expected = Tuple.product(shape) * div(bitsize, 8)
unless actual == expected do
raise ArgumentError,
"unexpected size for tensor data, expected #{expected} bytes got: #{actual} bytes"
end
%{t | data: %B{state: binary}}
end
else
defp from_binary(t, binary) when is_binary(binary), do: %{t | data: %B{state: binary}}
end
defp from_binary(t, other), do: from_binary(t, IO.iodata_to_binary(other))
@impl true
def to_binary(%{type: {_backend_options, size}} = t, limit) do
limit = limit * div(size, 8)
binary = to_binary(t)
if byte_size(binary) == limit do
binary
else
binary_part(binary, 0, limit)
end
end
defp to_binary(%T{data: %{state: data}}), do: data
@impl true
def backend_copy(tensor, backend, opts) do
backend_transfer(tensor, backend, opts)
end
@impl true
def backend_transfer(tensor, Nx.Tensor, _opts) do
tensor
end
def backend_transfer(tensor, Nx.BinaryBackend, _opts) do
tensor
end
def backend_transfer(tensor, backend, opts) do
backend.from_binary(tensor, to_binary(tensor), opts)
end
@impl true
def backend_deallocate(_tensor) do
:ok
end
@impl true
def to_batched(out, %{type: {_, size}} = tensor, opts) do
leftover = opts[:leftover]
batch_size = elem(out.shape, 0)
axis_size = elem(tensor.shape, 0)
remainder = rem(axis_size, batch_size)
num_full_batches = div(axis_size, batch_size)
range =
if remainder != 0 and leftover == :repeat do
0..num_full_batches
else
0..(num_full_batches - 1)
end
binary = to_binary(tensor)
batch_bytes = Nx.size(out) * div(size, 8)
Stream.map(range, fn
^num_full_batches ->
before = num_full_batches * batch_bytes
available = byte_size(binary) - before
missing = batch_bytes - available
from_binary(out, [binary_part(binary, before, available), binary_part(binary, 0, missing)])
i ->
from_binary(out, binary_part(binary, i * batch_bytes, batch_bytes))
end)
end
## Shape
@impl true
def reshape(out, tensor), do: from_binary(out, to_binary(tensor))
@impl true
def squeeze(out, tensor, _axes), do: from_binary(out, to_binary(tensor))
## Broadcast
@impl true
def broadcast(out, t, shape, axes) do
from_binary(out, broadcast_data(t, shape, axes))
end
defp broadcast_data(%{shape: shape} = t, shape),
do: to_binary(t)
defp broadcast_data(t, shape),
do: broadcast_data(t, shape, Nx.Shape.broadcast_axes(t.shape, shape))
defp broadcast_data(%T{shape: {}} = t, shape, []) do
t
|> to_binary()
|> :binary.copy(Nx.size(shape))
end
defp broadcast_data(%T{shape: old_shape, type: {_, size}} = t, new_shape, axes) do
chunk_size = size * Nx.size(old_shape)
new_shape
|> Tuple.to_list()
|> unary_broadcast(0, old_shape, 0, axes, to_binary(t), chunk_size)
|> IO.iodata_to_binary()
end
# Old and new match
defp unary_broadcast([dim | dims], axis, old_shape, old_pos, [axis | axes], data, chunk_size)
when elem(old_shape, old_pos) == dim do
chunk_size = div(chunk_size, dim)
for <<chunk::size(chunk_size)-bitstring <- data>> do
unary_broadcast(dims, axis + 1, old_shape, old_pos + 1, axes, chunk, chunk_size)
end
end
# Implicit broadcasting
defp unary_broadcast([dim | dims], axis, old_shape, old_pos, [axis | axes], data, chunk_size)
when elem(old_shape, old_pos) == 1 do
for _ <- 1..dim do
unary_broadcast(dims, axis + 1, old_shape, old_pos + 1, axes, data, chunk_size)
end
end
# Explicit broadcasting (unmapped axes)
defp unary_broadcast([dim | dims], axis, old_shape, old_pos, axes, data, chunk_size) do
for _ <- 1..dim do
unary_broadcast(dims, axis + 1, old_shape, old_pos, axes, data, chunk_size)
end
end
defp unary_broadcast([], _axis, _old_shape, _old_pos, [], data, _chunk_size) do
data
end
## Shape
@impl true
def transpose(out, %T{shape: shape, type: {_, size}} = t, axes) do
data = to_binary(t)
{list, min, max} = transpose_axes(shape, axes)
weighted_shape = weighted_shape(shape, size)
# The chunk size is computed based on all dimensions
# before the minimum one being changed. For example,
# for {0, 1, 2, 3} and the swap is between 1 and 2,
# the chunk_size will be d1 * d2 * d3 * size.
chunk_size = weighted_chunk(weighted_shape, min, size)
# All of the major dimensions not being transposed can be
# read at once. For example, for {0, 1, 2, 3} and the swap
# is between 1 and 2, the read_size will be d3 * size.
read_size = weighted_chunk(weighted_shape, max + 1, size)
# And now how we will traverse
traverse_list = Enum.map(list, &Enum.fetch!(weighted_shape, &1))
data =
for <<chunk::size(chunk_size)-bitstring <- data>> do
weighted_traverse(traverse_list, chunk, read_size)
end
from_binary(out, data)
end
defp transpose_axes(shape, axes) do
size = tuple_size(shape)
{axes, min} = transpose_min(axes, 0)
{axes, max} = transpose_max(Enum.reverse(axes), size - 1)
{axes, min, max}
end
defp transpose_min([head | tail], head), do: transpose_min(tail, head + 1)
defp transpose_min(tail, head), do: {tail, head}
defp transpose_max([head | tail], head), do: transpose_max(tail, head - 1)
defp transpose_max(tail, head), do: {Enum.reverse(tail), head}
## Pad
# We ignore the out because we need to recur over the shape
# as we transpose and build the rest.
@impl true
def pad(out, t, pad_value, padding_config) do
pad_value = %{pad_value | type: out.type} |> as_type(pad_value) |> to_binary()
case t.shape do
{} ->
t
{_} ->
[{edge_low, edge_high, interior}] = padding_config
pad_last_dim(t, pad_value, edge_low, edge_high, interior)
_ ->
permutation = for i <- 0..(Nx.rank(t) - 2), do: i
permutation = [Nx.rank(t) - 1 | permutation]
for {edge_low, edge_high, interior} <- Enum.reverse(padding_config), reduce: t do
acc ->
Nx.transpose(pad_last_dim(acc, pad_value, edge_low, edge_high, interior),
axes: permutation
)
end
end
end
# Add padding to the high and low ends of the last dimension of a tensor
defp pad_last_dim(
%T{shape: shape, type: {_, size} = type} = t,
value,
edge_low,
edge_high,
interior
) do
view = aggregate_axes(to_binary(t), [tuple_size(shape) - 1], shape, size)
new_shape = pad_in_dim(shape, tuple_size(shape) - 1, edge_low, edge_high, interior)
edge_high_padding =
if edge_high <= 0,
do: <<>>,
else: for(_ <- 1..edge_high, into: <<>>, do: value)
edge_low_padding =
if edge_low <= 0,
do: <<>>,
else: for(_ <- 1..edge_low, into: <<>>, do: value)
interior_padding =
if interior == 0,
do: <<>>,
else: for(_ <- 1..interior, into: <<>>, do: value)
interior_padding_size = interior * size
interior_padded =
for bin <- view do
padded =
for <<dim::size(size)-bitstring <- bin>>, into: <<>> do
<<dim::size(size)-bitstring, interior_padding::bitstring>>
end
new_bytes = byte_size(padded) * 8 - interior_padding_size
<<new_bin::size(new_bytes)-bitstring, _::bitstring>> = padded
new_bin
end
data =
for bin <- interior_padded, into: <<>> do
cond do
edge_low < 0 and edge_high < 0 ->
low_byte = abs(edge_low) * size
high_byte = abs(edge_high) * size
new_bytes = byte_size(bin) * 8 - high_byte - low_byte
<<_::size(low_byte)-bitstring, new_bin::size(new_bytes)-bitstring, _::bitstring>> =
bin
new_bin
edge_low < 0 and edge_high >= 0 ->
low_byte = abs(edge_low) * size
<<_::size(low_byte)-bitstring, new_bin::bitstring>> = bin
<<new_bin::bitstring, edge_high_padding::bitstring>>
edge_low >= 0 and edge_high < 0 ->
high_byte = abs(edge_high) * size
new_bytes = byte_size(bin) * 8 - high_byte
<<new_bin::size(new_bytes)-bitstring, _::bitstring>> = bin
<<edge_low_padding::bitstring, new_bin::bitstring>>
true ->
<<edge_low_padding::bitstring, bin::bitstring, edge_high_padding::bitstring>>
end
end
from_binary(%{t | type: type, shape: new_shape}, data)
end
defp pad_in_dim(shape, dim, edge_low, edge_high, interior) do
dim_size = elem(shape, dim)
interior_padding_factor = (dim_size - 1) * interior
new_dim = dim_size + interior_padding_factor + edge_high + edge_low
put_elem(shape, dim, new_dim)
end
@impl true
def reverse(out, %{type: {_, size}, shape: shape} = t, axes) do
data = to_binary(t)
weighted_shape = weighted_shape(shape, size)
# Nx guaranteex axes is sorted and non-empty.
min = List.first(axes)
max = List.last(axes) + 1
# The chunk size is computed based on all dimensions
# before the minimum one being changed. For example,
# for {0, 1, 2, 3} and the reverse is between 1 and 2,
# the chunk_size will be d1 * d2 * d3 * size.
chunk_size = weighted_chunk(weighted_shape, min, size)
# All of the major dimensions not being reverse can be
# read at once. For example, for {0, 1, 2, 3} and the reverse
# is between 1 and 2, the read_size will be d3 * size.
read_size = weighted_chunk(weighted_shape, max, size)
# And now how we will traverse
traverse =
weighted_shape
|> Enum.take(max)
|> Enum.drop(min)
|> reverse_traverse(min, axes)
data =
for <<chunk::size(chunk_size)-bitstring <- data>> do
weighted_traverse(traverse, chunk, read_size)
end
from_binary(out, data)
end
defp reverse_traverse([head | tail], axis, axes) do
if axis in axes do
[&Enum.reverse/1, head | reverse_traverse(tail, axis + 1, axes)]
else
[head | reverse_traverse(tail, axis + 1, axes)]
end
end
defp reverse_traverse([], _axis, _axes), do: []
## Two-element
@impl true
def dot(out, left, contract_axes1, [], right, contract_axes2, []) do
# dot/4 is directed to this specific clause so we can keep a more efficient implementation
# for non-batched dot products. See the clause below for batched dot products
data = bin_dot(left, contract_axes1, right, contract_axes2, out.type)
from_binary(out, data)
end
def dot(
out,
%{shape: left_shape, type: {_, left_size}, names: left_names} = left,
left_contract_axes,
left_batch_axes,
%{shape: right_shape, type: {_, right_size}, names: right_names} = right,
right_contract_axes,
right_batch_axes
) do
left_binary = to_binary(left)
right_binary = to_binary(right)
left_batch_contract_axes =
Enum.map(left_contract_axes, fn axis -> axis - length(left_batch_axes) end)
right_batch_contract_axes =
Enum.map(right_contract_axes, fn axis -> axis - length(right_batch_axes) end)
{left_batch_shape, _left_batch_names} =
Nx.Shape.contract(left_shape, left_batch_axes, left_names, false)
{right_batch_shape, _right_batch_names} =
Nx.Shape.contract(right_shape, right_batch_axes, right_names, false)
left_batch_item_length = Nx.size(left_batch_shape)
right_batch_item_length = Nx.size(right_batch_shape)
batch_count = Enum.reduce(left_batch_axes, 1, fn x, acc -> elem(left_shape, x) * acc end)
range = if batch_count == 0, do: [], else: 0..(batch_count - 1)
left_batch_item_template = %{left | shape: left_batch_shape}
right_batch_item_template = %{right | shape: right_batch_shape}
bin_result =
for index <- range do
left_offset = index * left_batch_item_length
right_offset = index * right_batch_item_length
left_offset_bits = left_offset * left_size
right_offset_bits = right_offset * right_size
left_batch_item_bits = left_batch_item_length * left_size
right_batch_item_bits = right_batch_item_length * right_size
<<_::bitstring-size(left_offset_bits),
left_batch_item_binary::bitstring-size(left_batch_item_bits),
_::bitstring>> = left_binary
<<_::bitstring-size(right_offset_bits),
right_batch_item_binary::bitstring-size(right_batch_item_bits),
_::bitstring>> = right_binary
bin_dot(
from_binary(left_batch_item_template, left_batch_item_binary),
left_batch_contract_axes,
from_binary(right_batch_item_template, right_batch_item_binary),
right_batch_contract_axes,
out.type
)
end
from_binary(out, bin_result)
end
defp bin_dot(%{type: t1} = left, contract_axes1, %{type: t2} = right, contract_axes2, type) do
{left, left_contract_axes} = bin_dot_transpose_contract_axes(left, contract_axes1)
{right, right_contract_axes} = bin_dot_transpose_contract_axes(right, contract_axes2)
bin_zip_reduce(left, left_contract_axes, right, right_contract_axes, type, 0, fn
lhs, rhs, acc ->
res = binary_to_number(lhs, t1) * binary_to_number(rhs, t2) + acc
{res, res}
end)
end
defp bin_dot_transpose_contract_axes(tensor, contract_axes) do
# The intution here is that we can pre-condense the contracting axes into a
# single dimension, which will then be contracted through bin_zip_reduce below.
# This takes a shape {a, m, n, b} which contracts on m, n and turns it into
# {a, b, m * n}, contracting on the last dimension. This is necessary because
# bin_zip_reduce and aggregate_axes are order independent but dot depends
# on the axes order.
axes = Nx.axes(tensor)
remaining_axes =
contract_axes
|> Enum.sort(:desc)
|> Enum.reduce(axes, &List.delete_at(&2, &1))
transpose_axes = remaining_axes ++ contract_axes
transposed =
if transpose_axes == axes do
tensor
else
{shape, names} = Nx.Shape.transpose(tensor.shape, transpose_axes, tensor.names)
transpose(%{tensor | shape: shape, names: names}, tensor, transpose_axes)
end
{kept, contracted} =
transposed.shape
|> Tuple.to_list()
|> Enum.split(length(remaining_axes))
kept_shape = List.to_tuple(kept)
kept_size = tuple_size(kept_shape)
reduced_shape = Tuple.insert_at(kept_shape, kept_size, Enum.product(contracted))
{%{transposed | shape: reduced_shape, names: List.duplicate(nil, tuple_size(reduced_shape))},
[kept_size]}
end
## Element wise ternary ops
@impl true
def select(out, %{shape: {}} = pred, on_true, on_false) do
result =
if scalar_to_number(pred) == 0 do
on_false |> broadcast_data(out.shape) |> binary_to_binary(on_false.type, out.type, & &1)
else
on_true |> broadcast_data(out.shape) |> binary_to_binary(on_true.type, out.type, & &1)
end
from_binary(out, result)
end
def select(%{shape: shape, type: type} = out, pred, on_true, on_false) do
%T{type: {_, pred_size} = pred_type} = pred
%T{type: {_, left_size} = left_type} = on_true
%T{type: {_, right_size} = right_type} = on_false
pred_data = to_binary(pred)
on_true_data = broadcast_data(on_true, shape)
on_false_data = broadcast_data(on_false, shape)
data =
for i <- 0..(Nx.size(shape) - 1), into: <<>> do
pred =
match_types [pred_type] do
consumed = i * pred_size
<<_::size(consumed)-bitstring, match!(pred, 0), _::bitstring>> = pred_data
read!(pred, 0)
end
result =
if pred == 0 do
match_types [right_type] do
consumed = i * right_size
<<_::size(consumed)-bitstring, match!(x, 0), _::bitstring>> = on_false_data
read!(x, 0)
end
else
match_types [left_type] do
consumed = i * left_size
<<_::size(consumed)-bitstring, match!(x, 0), _::bitstring>> = on_true_data
read!(x, 0)
end
end
number_to_binary(result, type)
end
from_binary(out, data)
end
## Element wise bin ops
for fun <-
[:add, :subtract, :multiply, :pow, :remainder, :divide, :atan2, :min, :max, :quotient] ++
[:bitwise_and, :bitwise_or, :bitwise_xor, :left_shift, :right_shift] ++
[:equal, :not_equal, :greater, :less, :greater_equal, :less_equal] ++
[:logical_and, :logical_or, :logical_xor] do
capture = Macro.var(:"element_#{fun}", __MODULE__)
@impl true
def unquote(fun)(out, left, right) do
element_wise_bin_op(out, left, right, &(unquote(capture) / 3))
end
end
defp element_wise_bin_op(%{type: type} = out, %{shape: {}} = left, right, fun) do
number = scalar_to_number(left)
data =
binary_to_binary(to_binary(right), right.type, type, fn x ->
fun.(type, number, x)
end)
from_binary(out, data)
end
defp element_wise_bin_op(%{type: type} = out, left, %{shape: {}} = right, fun) do
number = scalar_to_number(right)
data =
binary_to_binary(to_binary(left), left.type, type, fn x ->
fun.(type, x, number)
end)
from_binary(out, data)
end
defp element_wise_bin_op(%{shape: shape, type: type} = out, left, right, fun) do
%T{type: {_, left_size} = left_type} = left
%T{type: {_, right_size} = right_type} = right
count = Nx.size(shape)
left_data = broadcast_data(left, shape)
right_data = broadcast_data(right, shape)
data =
match_types [left_type, right_type, type] do
for i <- 0..(count - 1), into: <<>> do
left_consumed = i * left_size
<<_::size(left_consumed)-bitstring, match!(x, 0), _::bitstring>> = left_data
x = read!(x, 0)
right_consumed = i * right_size
<<_::size(right_consumed)-bitstring, match!(y, 1), _::bitstring>> = right_data
y = read!(y, 1)
<<write!(fun.(type, x, y), 2)>>
end
end
from_binary(out, data)
end
defp element_add(_, a, b), do: Complex.add(a, b)
defp element_subtract(_, a, b), do: Complex.subtract(a, b)
defp element_multiply(_, a, b), do: Complex.multiply(a, b)
defp element_divide(_, a, b), do: Complex.divide(a, b)
defp element_quotient(_, a, b), do: div(a, b)
defp element_remainder(_, a, b) when is_integer(a) and is_integer(b), do: rem(a, b)
defp element_remainder(_, a, b), do: :math.fmod(a, b)
defp element_atan2(_, a, b), do: Complex.atan2(a, b)
defp element_max(_, :nan, _), do: :nan
defp element_max(_, _, :nan), do: :nan
defp element_max(_, :infinity, _), do: :infinity
defp element_max(_, _, :infinity), do: :infinity
defp element_max(_, :neg_infinity, x), do: x
defp element_max(_, x, :neg_infinity), do: x
defp element_max(_, a, b) when is_number(a) and is_number(b), do: max(a, b)
defp element_min(_, :nan, _), do: :nan
defp element_min(_, _, :nan), do: :nan
defp element_min(_, :infinity, x), do: x
defp element_min(_, x, :infinity), do: x
defp element_min(_, :neg_infinity, _), do: :neg_infinity
defp element_min(_, _, :neg_infinity), do: :neg_infinity
defp element_min(_, a, b) when is_number(a) and is_number(b), do: min(a, b)
defp element_pow({type, _}, a, b) when type in [:s, :u], do: Integer.pow(a, b)
defp element_pow(_, a, b), do: Complex.pow(a, b)
defp element_bitwise_and(_, a, b), do: :erlang.band(a, b)
defp element_bitwise_or(_, a, b), do: :erlang.bor(a, b)
defp element_bitwise_xor(_, a, b), do: :erlang.bxor(a, b)
defp element_left_shift(_, a, b) when is_number(b) and b >= 0,
do: :erlang.bsl(a, b)
defp element_left_shift(_, _, b), do: raise(ArgumentError, "cannot left shift by #{b}")
defp element_right_shift(_, a, b) when is_number(b) and b >= 0,
do: :erlang.bsr(a, b)
defp element_right_shift(_, _, b), do: raise(ArgumentError, "cannot right shift by #{b}")
defp element_equal(_, :nan, _), do: 0
defp element_equal(_, _, :nan), do: 0
defp element_equal(_, a, b), do: boolean_as_number(a == b)
defp element_not_equal(_, :nan, _), do: 1
defp element_not_equal(_, _, :nan), do: 1
defp element_not_equal(_, a, b), do: boolean_as_number(a != b)
defp element_logical_and(_, a, b), do: boolean_as_number(as_boolean(a) and as_boolean(b))
defp element_logical_or(_, a, b), do: boolean_as_number(as_boolean(a) or as_boolean(b))
defp element_logical_xor(_, a, b), do: boolean_as_number(as_boolean(a) != as_boolean(b))
defp element_greater(_, :nan, _), do: 0
defp element_greater(_, _, :nan), do: 0
defp element_greater(_, x, x), do: 0
defp element_greater(_, :infinity, _), do: 1
defp element_greater(_, _, :neg_infinity), do: 1
defp element_greater(_, :neg_infinity, _), do: 0
defp element_greater(_, _, :infinity), do: 0
defp element_greater(_, a, b), do: boolean_as_number(a > b)
defp element_less(_, :nan, _), do: 0
defp element_less(_, _, :nan), do: 0
defp element_less(_, :infinity, _), do: 0
defp element_less(_, _, :neg_infinity), do: 0
defp element_less(_, x, x), do: 0
defp element_less(_, _, :infinity), do: 1
defp element_less(_, :neg_infinity, _), do: 1
defp element_less(_, a, b), do: boolean_as_number(a < b)
defp element_greater_equal(_, :nan, _), do: 0
defp element_greater_equal(_, _, :nan), do: 0
defp element_greater_equal(_, x, x), do: 1
defp element_greater_equal(_, :neg_infinity, _), do: 0
defp element_greater_equal(_, _, :infinity), do: 0
defp element_greater_equal(_, :infinity, _), do: 1
defp element_greater_equal(_, _, :neg_infinity), do: 1
defp element_greater_equal(_, a, b), do: boolean_as_number(a >= b)
defp element_less_equal(_, :nan, _), do: 0
defp element_less_equal(_, _, :nan), do: 0
defp element_less_equal(_, _, :infinity), do: 1
defp element_less_equal(_, :neg_infinity, _), do: 1
defp element_less_equal(_, x, x), do: 1
defp element_less_equal(_, :infinity, _), do: 0
defp element_less_equal(_, _, :neg_infinity), do: 0
defp element_less_equal(_, a, b), do: boolean_as_number(a <= b)
defp as_boolean(n) when n == 0, do: false
defp as_boolean(%Complex{re: re, im: im}) when re == 0 and im == 0, do: false
defp as_boolean(_), do: true
defp boolean_as_number(true), do: 1
defp boolean_as_number(false), do: 0
## Element wise unary ops
for {name, {_desc, code, _formula}} <- Nx.Shared.unary_math_funs() do
@impl true
def unquote(name)(out, tensor) do
element_wise_unary_op(out, tensor, fn x -> unquote(code) end)
end
end
@impl true
def count_leading_zeros(out, %{type: {_, size}} = tensor) do
element_wise_bit_op(out, tensor, &element_clz(&1, size))
end
@impl true
def population_count(out, tensor) do
element_wise_bit_op(out, tensor, &element_popcount(&1, 0))
end
defp element_wise_bit_op(out, %{type: {_, size}} = tensor, fun) do
data =
match_types [out.type] do
for <<seg::unsigned-size(size)-native <- to_binary(tensor)>>, into: <<>> do
<<write!(fun.(seg), 0)>>
end
end
from_binary(out, data)
end
@impl true
def abs(out, tensor), do: element_wise_unary_op(out, tensor, &Complex.abs/1)
@impl true
def conjugate(out, tensor), do: element_wise_unary_op(out, tensor, &Complex.conjugate/1)
@impl true
def real(%{type: {_, component_size}} = out, %{type: {:c, _}} = tensor) do
data = to_binary(tensor)
result =
for <<real::bitstring-size(component_size), _::bitstring-size(component_size) <- data>>,
into: <<>>,
do: real
from_binary(out, result)
end
@impl true
def imag(%{type: {_, component_size}} = out, %{type: {:c, _}} = tensor) do
data = to_binary(tensor)
result =
for <<_::bitstring-size(component_size), imag::bitstring-size(component_size) <- data>>,
into: <<>>,
do: imag
from_binary(out, result)
end
@impl true
def bitwise_not(out, tensor), do: element_wise_unary_op(out, tensor, &:erlang.bnot/1)
@impl true
def is_nan(out, %{type: {t, _}}) when t in [:u, :s] do
# integers cannot represent nans, so we can just create
# a zero boolean tensor
# 8 bits per entry because we return u8
size = Nx.size(out.shape) * 8
from_binary(out, <<0::size(size)>>)
end
def is_nan(out, tensor) do
element_wise_unary_op(out, tensor, fn
%Complex{re: :nan} -> 1
%Complex{im: :nan} -> 1
:nan -> 1
_ -> 0
end)
end
@impl true
def is_infinity(out, %{type: {t, _}}) when t in [:u, :s] do
# integers cannot represent nans, so we can just create
# a zero boolean tensor
# 8 bits per entry because we return u8
size = Nx.size(out.shape) * 8
from_binary(out, <<0::size(size)>>)
end
def is_infinity(out, tensor) do
element_wise_unary_op(out, tensor, fn
%Complex{re: re} when re in [:infinity, :neg_infinity] -> 1
%Complex{im: im} when im in [:infinity, :neg_infinity] -> 1
:infinity -> 1
:neg_infinity -> 1
_ -> 0
end)
end
@impl true
def ceil(out, tensor), do: element_wise_unary_op(out, tensor, &:erlang.ceil/1)
@impl true
def floor(out, tensor), do: element_wise_unary_op(out, tensor, &:erlang.floor/1)
@impl true
def negate(out, tensor), do: element_wise_unary_op(out, tensor, &Complex.negate/1)
@impl true
def round(out, tensor), do: element_wise_unary_op(out, tensor, &:erlang.round/1)
@impl true
def sign(out, tensor), do: element_wise_unary_op(out, tensor, &element_sign/1)
defp element_sign(n) when n < 0, do: -1
defp element_sign(n) when n > 0, do: 1
defp element_sign(n), do: n
# https://en.wikipedia.org/wiki/Hamming_weight
# There are algorithms with faster worst case but they are size specific.
# The implementation below is also the most efficient for low counts. Given
# our integers are always 64 bits internally, we will have a lot of zeros
# internally, so this should be the fastest.
defp element_popcount(0, count), do: count
defp element_popcount(n, count), do: element_popcount(n &&& n - 1, count + 1)
defp element_wise_unary_op(out, tensor, fun) do
data = binary_to_binary(to_binary(tensor), tensor.type, out.type, fun)
from_binary(out, data)
end
defp element_clz(0, size), do: size
defp element_clz(n, 64), do: element_clz64(n)
defp element_clz(n, 32), do: element_clz32(n)
defp element_clz(n, 16), do: element_clz16(n)
defp element_clz(n, 8), do: element_clz8(n)
defp element_clz64(num) do
case num &&& 0xFFFFFFFF00000000 do
0 -> 32 + element_clz32(num)
_ -> element_clz32(num >>> 32)
end
end
defp element_clz32(num) do
case num &&& 0xFFFF0000 do
0 -> 16 + element_clz16(num)
_ -> element_clz16(num >>> 16)
end
end
defp element_clz16(num) do
case num &&& 0xFF00 do
0 -> 8 + element_clz8(num)
_ -> element_clz8(num >>> 8)
end
end
defp element_clz8(num) do
case num &&& 0xF0 do
0 -> 4 + element_clz4(num)
_ -> element_clz4(num >>> 4)
end
end
defp element_clz4(num) do
case num &&& 0xC do
0 -> 2 + element_clz2(num)
_ -> element_clz2(num >>> 2)
end
end
defp element_clz2(0), do: 2
defp element_clz2(1), do: 1
defp element_clz2(_), do: 0
## Inspect
@impl true
def inspect(tensor, inspect_opts) do
limit = inspect_opts.limit
binary = Nx.to_binary(tensor, if(limit == :infinity, do: [], else: [limit: limit + 1]))
Nx.Backend.inspect(tensor, binary, inspect_opts)
end
## Conv
@impl true
def conv(out, t, k, opts) do
padding = opts[:padding]
strides = opts[:strides]
input_dilation = opts[:input_dilation]
kernel_dilation = opts[:kernel_dilation]
feature_groups = opts[:feature_group_size]
batch_groups = opts[:batch_group_size]
input_permutation = opts[:input_permutation]
kernel_permutation = opts[:kernel_permutation]
output_permutation = opts[:output_permutation]
output_permutation =
output_permutation
|> Enum.with_index()
|> Enum.sort()
|> Enum.map(&elem(&1, 1))
# Consider an image representation, the input shape should be:
# {batch, channels, height, width}
#
# The kernel then has the following shape:
# {num_filters, channels, filter_height, filter_width}
#
# The output type is merged between the input tensor
# and the input kernel, both inputs must be floating types
#
# The output shape is a product of the batch size,
# number of filters in the input kernel, and the transformation
# on the spatial dimensions.
#
# The shape of each spatial dimension is calculated as:
#
# (spatial_dim - filter_size + 2 * padding_size) / stride + 1
#
# where spatial dim is the current spatial dimension size, filter size is
# the size of the corresponding spatial dimension in the kernel,
# padding size is the amount of padding applied to either side of the
# spatial dimension, and stride is the input stride
#
# The final shape is then given as:
# {batch, num_filters, spatial_dim0, spatial_dim1, ...}
%T{type: {_, input_size} = input_type} = t = Nx.transpose(t, axes: input_permutation)
%T{type: {_, kernel_size} = kernel_type} = k = Nx.transpose(k, axes: kernel_permutation)
%{type: output_type, shape: output_shape, names: output_names} = out
inverse_output_permutation =
output_permutation |> Enum.with_index() |> Enum.sort() |> Enum.map(&elem(&1, 1))
{untransposed_shape, untransposed_names} =
Nx.Shape.transpose(output_shape, inverse_output_permutation, output_names)
untransposed_out = %{out | names: untransposed_names, shape: untransposed_shape}
# We need to dilate the spatial dimensions of the kernel first...
dilation_padding = [
{0, 0, 0},
{0, 0, 0} | Enum.map(kernel_dilation, &{0, 0, &1 - 1})
]
%T{shape: kernel_shape} = k = Nx.pad(k, 0, dilation_padding)
# The size of the "window" or the size of each filter
# removes the first two dimensions of the kernel
#
# This "window" is applied `num_filters` times across
# the input tensors spatial dimensions
filter_shape =
kernel_shape
|> Tuple.delete_at(0)
|> Tuple.delete_at(0)
num_filters = elem(kernel_shape, 0)
num_input_channels = elem(kernel_shape, 1)
# We first pad the input tensor with the following semantics
# :valid - no padding
# :same - pad with 0 such that the input's spatial dims
# remain unchanged WITHOUT considering strides
# general - pad with the given padding configuration
#
# Padding configuration is guaranteed to always be provided
# as a list because it is handled in the Nx module before
# lowering to the implementation; however, the padding
# configuration only accounts for spatial dims
spatial_padding_config =
Enum.zip_with(padding, input_dilation, fn {lo, hi}, dilation ->
{lo, hi, dilation - 1}
end)
padding_config = [
{0, 0, 0},
{0, 0, 0} | spatial_padding_config
]
%T{shape: padded_shape} = padded_t = Nx.pad(t, 0, padding_config)
single_data_dims = Tuple.delete_at(padded_shape, 0)
batch_size = Nx.size(single_data_dims) * input_size
# We will traverse the input tensor exactly the same as we traversed
# the binary in window_reduce, but the window is equal to the filter
# size of the kernel plus the channel size of the input tensor
window_shape = Tuple.insert_at(filter_shape, 0, num_input_channels)
input_data = to_binary(padded_t)
kernel_data = to_binary(k)
filter_groups_with_index =
split_into_feature_groups(kernel_data, kernel_shape, kernel_type, feature_groups)
batch_groups_with_index =
split_into_batch_groups(input_data, padded_shape, input_type, batch_groups)
# If we're not splitting across input channels, we're splitting across input batches
# So we split the filters into groups to apply to the corresponding batch
filter_groups_with_index =
if batch_groups > 1,
do: Enum.chunk_every(filter_groups_with_index, div(num_filters, batch_groups)),
else: filter_groups_with_index
batch_weighted_shape =
weighted_shape(Tuple.delete_at(padded_shape, 0), input_size, window_shape)
# We calculate our "anchors" using just the spatial dimensions
# but they also need to consider the depth or channels of the input
# tensor, so we always anchor on the `0th` channel
padded_spatial_dims =
padded_shape
|> Tuple.delete_at(0)
|> Tuple.delete_at(0)
anchors = Enum.sort(make_anchors(padded_spatial_dims, strides, filter_shape))
output_data =
for {batch_group, batch_group_index} <- batch_groups_with_index, into: <<>> do
current_filter_group_with_index =
if batch_groups > 1,
do: Enum.at(filter_groups_with_index, batch_group_index),
else: filter_groups_with_index
# Traverse the batch dim first
for <<batch::size(batch_size)-bitstring <- batch_group>>,
# Traverse the filters next, this allows us to rebuild
# the resulting binary correctly
{filter, feature_group} <- current_filter_group_with_index,
# Then we traverse the spatial dimension, applying
# the filter at each step
anchor <- anchors,
into: <<>> do
offset =
weighted_offset(batch_weighted_shape, [feature_group * num_input_channels | anchor])
# The shape of the window is {channels} + filter_shape
# The shape of the kernel is {num_filters, channels} + filter_shape
window =
batch_weighted_shape
|> weighted_traverse(batch, input_size, offset)
|> IO.iodata_to_binary()
# The receptive field size of each binary in bytes
input_field_size = Nx.size(filter_shape) * input_size
filter_field_size = Nx.size(filter_shape) * kernel_size
# For each channel in both filter and input...
# The output from a single filter being applied over a window
# of the input tensor is the sum of the element-wise products
values =
for i <- 0..(num_input_channels - 1) do
current_input_pos = i * input_field_size
current_filter_pos = i * filter_field_size
<<_::size(current_input_pos)-bitstring, input_receptive_field::bitstring>> = window
<<_::size(current_filter_pos)-bitstring, filter_receptive_field::bitstring>> =
filter
for j <- 0..(Nx.size(filter_shape) - 1) do
x =
match_types [input_type] do
left_consumed = j * input_size
<<_::size(left_consumed)-bitstring, match!(x, 0), _::bitstring>> =
input_receptive_field
read!(x, 0)
end
y =
match_types [kernel_type] do
right_consumed = j * kernel_size
<<_::size(right_consumed)-bitstring, match!(y, 0), _::bitstring>> =
filter_receptive_field
read!(y, 0)
end
x * y
end
end
values
|> List.flatten()
|> Enum.reduce(&+/2)
|> number_to_binary(output_type)
end
end
Nx.transpose(from_binary(untransposed_out, output_data), axes: output_permutation)
end
defp split_into_feature_groups(data, shape, {_, size}, groups) do
group_size = div(Nx.size(shape) * size, groups)
data_size = div(Nx.size(shape) * size, elem(shape, 0))
for i <- 0..(groups - 1),
offset = group_size * i,
<<_::size(offset)-bitstring, data_group::size(group_size)-bitstring, _::bitstring>> =
data,
<<out_data::size(data_size)-bitstring <- data_group>>,
do: {out_data, i}
end
defp split_into_batch_groups(data, shape, {_, size}, groups) do
item_size = div(Nx.size(shape) * size, elem(shape, 0))
num_groups = div(elem(shape, 0), groups)
output_batch_groups =
for i <- 0..(num_groups - 1),
j <- 0..(groups - 1) do
offset = (i + j * num_groups) * item_size
<<_::size(offset)-bitstring, item::size(item_size)-bitstring, _::bitstring>> = data
item
end
output_batch_groups |> Enum.with_index() |> Enum.map(fn {x, i} -> {x, rem(i, groups)} end)
end
@impl true
def cholesky(
%T{type: output_type, shape: output_shape} = out,
%T{type: input_type} = tensor
) do
data = to_binary(tensor)
rank = tuple_size(output_shape)
n = elem(output_shape, rank - 1)
l =
bin_batch_reduce(data, n * n, input_type, <<>>, fn matrix, acc ->
l = B.Matrix.cholesky(matrix, input_type, {n, n}, output_type)
acc <> l
end)
from_binary(out, l)
end
@impl true
def qr(
{%{shape: q_holder_shape, type: output_type} = q_holder,
%{shape: r_holder_shape, type: output_type} = r_holder},
%{type: input_type, shape: input_shape} = tensor,
opts
) do
bin = to_binary(tensor)
rank = tuple_size(input_shape)
m = elem(q_holder_shape, rank - 2)
k = elem(q_holder_shape, rank - 1)
n = elem(r_holder_shape, rank - 1)
{q, r} =
bin_batch_reduce(bin, m * n, input_type, {<<>>, <<>>}, fn matrix, {q_acc, r_acc} ->
{q, r} = B.Matrix.qr(matrix, input_type, {m, n}, output_type, m, k, n, opts)
{q_acc <> q, r_acc <> r}
end)
{from_binary(q_holder, q), from_binary(r_holder, r)}
end
@impl true
def eigh(
{%{type: output_type} = eigenvals_holder, eigenvecs_holder},
%{type: input_type, shape: input_shape} = tensor,
opts
) do
bin = to_binary(tensor)
rank = tuple_size(input_shape)
n = elem(input_shape, rank - 1)
{eigenvals, eigenvecs} =
bin_batch_reduce(bin, n * n, input_type, {<<>>, <<>>}, fn matrix, {vals_acc, vecs_acc} ->
{vals, vecs} = B.Matrix.eigh(matrix, input_type, {n, n}, output_type, opts)
{vals_acc <> vals, vecs_acc <> vecs}
end)
{from_binary(eigenvals_holder, eigenvals), from_binary(eigenvecs_holder, eigenvecs)}
end
@impl true
def lu(
{%{type: p_type} = p_holder, %{type: l_type} = l_holder, %{type: u_type} = u_holder},
%{type: input_type, shape: input_shape} = tensor,
opts
) do
bin = to_binary(tensor)
rank = tuple_size(input_shape)
n = elem(input_shape, rank - 1)
{p, l, u} =
bin_batch_reduce(bin, n * n, input_type, {<<>>, <<>>, <<>>}, fn matrix,
{p_acc, l_acc, u_acc} ->
{p, l, u} = B.Matrix.lu(matrix, input_type, {n, n}, p_type, l_type, u_type, opts)
{p_acc <> p, l_acc <> l, u_acc <> u}
end)
{from_binary(p_holder, p), from_binary(l_holder, l), from_binary(u_holder, u)}
end
@impl true
def triangular_solve(
%{type: output_type} = out,
%{type: {_, a_size} = a_type, shape: a_shape} = a,
%{type: b_type, shape: b_shape} = b,
opts
) do
a_data = to_binary(a)
b_data = to_binary(b)
m = elem(a_shape, tuple_size(a_shape) - 1)
a_batch_byte_size = (m * m * a_size) |> div(8)
batches_num = byte_size(a_data) |> div(a_batch_byte_size)
a_batches =
Enum.map(
0..(batches_num - 1),
&binary_part(a_data, &1 * a_batch_byte_size, a_batch_byte_size)
)
b_batch_byte_size = byte_size(b_data) |> div(batches_num)
b_batches =
Enum.map(
0..(batches_num - 1),
&binary_part(b_data, &1 * b_batch_byte_size, b_batch_byte_size)
)
b_batch_shape =
if tuple_size(b_shape) == 1 do
b_shape
else
{a_batch_shape, _} = a_shape |> Tuple.to_list() |> Enum.split(-2)
{b_1d_batch_shape, [b_n]} = b_shape |> Tuple.to_list() |> Enum.split(-1)
{b_2d_batch_shape, [b_m, ^b_n]} = b_shape |> Tuple.to_list() |> Enum.split(-2)
case a_batch_shape do
^b_1d_batch_shape -> {b_n}
^b_2d_batch_shape -> {b_m, b_n}
end
end
[a_batches, b_batches]
|> Enum.zip_reduce(<<>>, fn [a, b], acc ->
acc <> B.Matrix.ts(a, a_type, {m, m}, b, b_type, b_batch_shape, output_type, opts)
end)
|> then(&from_binary(out, &1))
end
## Aggregation
@impl true
def all(out, %{type: type} = tensor, opts) do
data =
bin_reduce(tensor, out.type, 1, opts, fn bin, acc ->
res = if binary_to_number(bin, type) != 0, do: acc, else: 0
{res, res}
end)
from_binary(out, data)
end
@impl true
def any(out, %{type: type} = tensor, opts) do
data =
bin_reduce(tensor, out.type, 0, opts, fn bin, acc ->
res = if binary_to_number(bin, type) != 0, do: 1, else: acc
{res, res}
end)
from_binary(out, data)
end
@impl true
def sum(out, %{type: type} = tensor, opts) do
data =
bin_reduce(tensor, out.type, 0, opts, fn bin, acc ->
res = binary_to_number(bin, type) + acc
{res, res}
end)
from_binary(out, data)
end
@impl true
def product(out, %{type: type} = tensor, opts) do
data =
bin_reduce(tensor, out.type, 1, opts, fn bin, acc ->
res = binary_to_number(bin, type) * acc
{res, res}
end)
from_binary(out, data)
end
@impl true
def reduce_max(out, %{type: type} = tensor, opts) do
data =
bin_reduce(tensor, out.type, :first, opts, fn bin, acc ->
val = binary_to_number(bin, type)
res = if acc == :first, do: val, else: Kernel.max(acc, val)
{res, res}
end)
from_binary(out, data)
end
@impl true
def reduce_min(out, %{type: type} = tensor, opts) do
data =
bin_reduce(tensor, out.type, :first, opts, fn bin, acc ->
val = binary_to_number(bin, type)
res = if acc == :first, do: val, else: Kernel.min(acc, val)
{res, res}
end)
from_binary(out, data)
end
@impl true
def argmin(out, tensor, opts) do
comparator =
case opts[:tie_break] do
:high -> &<=/2
:low -> &</2
end
argmin_or_max(out, tensor, comparator, opts[:axis])
end
@impl true
def argmax(out, tensor, opts) do
comparator =
case opts[:tie_break] do
:high -> &>=/2
:low -> &>/2
end
argmin_or_max(out, tensor, comparator, opts[:axis])
end
defp argmin_or_max(out, %{type: type} = tensor, comparator, axis) do
opts = if axis, do: [axes: [axis]], else: []
data =
bin_reduce(tensor, out.type, {0, :first, -1}, opts, fn
bin, {i, cur_extreme_x, cur_extreme_i} ->
x = binary_to_number(bin, type)
if comparator.(x, cur_extreme_x) or cur_extreme_x == :first do
{i, {i + 1, x, i}}
else
{cur_extreme_i, {i + 1, cur_extreme_x, cur_extreme_i}}
end
end)
from_binary(out, data)
end
@impl true
def reduce(out, tensor, acc, opts, fun) do
each = %{tensor | shape: {}}
data =
bin_reduce(tensor, out.type, acc, opts, fn bin, acc ->
res = fun.(from_binary(each, bin), acc)
{res, res}
end)
from_binary(out, data)
end
@impl true
def window_reduce(out, tensor, acc, window_dimensions, opts, fun) do
padding_config = opts[:padding]
strides = opts[:strides]
dilations = opts[:window_dilations]
%T{shape: padded_shape, type: {_, size} = type} =
tensor = Nx.pad(tensor, acc, Enum.map(padding_config, &Tuple.append(&1, 0)))
acc = scalar_to_number(acc)
data = to_binary(tensor)
weighted_shape = weighted_shape(padded_shape, size, window_dimensions, dilations)
anchors = Enum.sort(make_anchors(padded_shape, strides, window_dimensions, dilations))
data =
match_types [type] do
for anchor <- anchors, into: <<>> do
offset = weighted_offset(weighted_shape, anchor, dilations)
window = IO.iodata_to_binary(weighted_traverse(weighted_shape, data, size, offset))
window_val =
for <<match!(x, 0) <- window>>,
reduce: acc,
do: (acc -> fun.(read!(x, 0), acc))
scalar_to_binary!(window_val, type)
end
end
from_binary(out, data)
end
@impl true
def window_sum(out, tensor, window_dimensions, opts) do
%{type: type} = out
init_value = number_to_binary(0, type)
init_value = from_binary(%{out | shape: {}, names: []}, init_value)
fun = fn a, b -> element_add(type, a, b) end
window_reduce(out, tensor, init_value, window_dimensions, opts, fun)
end
@impl true
def window_max(out, tensor, window_dimensions, opts) do
%{type: type} = out
init_value = Nx.Type.min_binary(type)
init_value = from_binary(%{out | shape: {}, names: []}, init_value)
fun = fn a, b -> element_max(type, a, b) end
window_reduce(out, tensor, init_value, window_dimensions, opts, fun)
end
@impl true
def window_min(out, tensor, window_dimensions, opts) do
%{type: type} = out
init_value = Nx.Type.max_binary(type)
init_value = from_binary(%{out | shape: {}, names: []}, init_value)
fun = fn a, b -> element_min(type, a, b) end
window_reduce(out, tensor, init_value, window_dimensions, opts, fun)
end
@impl true
def window_product(out, tensor, window_dimensions, opts) do
%{type: type} = out
init_value = number_to_binary(1, type)
init_value = from_binary(%{out | shape: {}, names: []}, init_value)
fun = fn a, b -> element_multiply(type, a, b) end
window_reduce(out, tensor, init_value, window_dimensions, opts, fun)
end
@impl true
def map(%{type: output_type} = out, %{type: {_, size}} = tensor, _opts, fun) do
data = to_binary(tensor)
template = %{tensor | shape: {}}
output_data =
for <<bin::size(size)-bitstring <- data>>, into: <<>> do
tensor = put_in(template.data.state, bin)
number_to_binary(scalar_to_number(fun.(tensor)), output_type)
end
from_binary(out, output_data)
end
@impl true
def window_scatter_max(out, tensor, source, init_value, window_dimensions, opts) do
select_and_scatter(
out,
tensor,
source,
&Nx.greater_equal/2,
window_dimensions,
opts,
init_value,
&Nx.add/2
)
end
@impl true
def window_scatter_min(out, tensor, source, init_value, window_dimensions, opts) do
select_and_scatter(
out,
tensor,
source,
&Nx.less_equal/2,
window_dimensions,
opts,
init_value,
&Nx.add/2
)
end
defp select_and_scatter(
%{type: {_, output_size} = output_type, shape: output_shape} = out,
t,
source,
select_fn,
window_dimensions,
opts,
init_value,
scatter_fn
) do
padding = opts[:padding]
strides = opts[:strides]
init_value = scalar_to_number(init_value)
%T{shape: padded_shape, type: {_, size} = type} =
tensor = Nx.pad(t, init_value, Enum.map(padding, &Tuple.append(&1, 0)))
input_data = to_binary(tensor)
input_weighted_shape = weighted_shape(padded_shape, size, window_dimensions)
input_anchors = Enum.sort(make_anchors(padded_shape, strides, window_dimensions))
%T{type: {_, source_size} = source_type} = source
source_data = to_binary(source)
output_windows =
for {anchor, i} <- Enum.with_index(input_anchors) do
offset = weighted_offset(input_weighted_shape, anchor)
window =
IO.iodata_to_binary(weighted_traverse(input_weighted_shape, input_data, size, offset))
# Get the index where `select_fn` is true
{_, index, _} =
match_types [type] do
<<match!(first_elem, 0), _::bitstring>> = window
for <<match!(x, 0) <- window>>, reduce: {0, 0, read!(first_elem, 0)} do
{cur_index, selected_index, acc} ->
if select_fn.(read!(x, 0), acc) == Nx.tensor(1, type: {:u, 8}) do
{cur_index + 1, cur_index, read!(x, 0)}
else
{cur_index + 1, selected_index, acc}
end
end
end
offset_from_anchor =
flattened_index_to_offset(index, Tuple.to_list(window_dimensions), 0, [])
absolute_index =
anchor
|> Enum.zip(offset_from_anchor)
|> Enum.map(fn {x, y} -> x + y end)
source_consumed = i * source_size
<<_::size(source_consumed)-bitstring, from_source::size(source_size)-bitstring,
_::bitstring>> = source_data
source_value = binary_to_number(from_source, source_type)
{source_value, absolute_index}
end
output_weighted_shape = weighted_shape(output_shape, output_size)
# Fold duplicate indices into one another using `scatter_fn` and sort
# by absolute offset
values_with_indices =
output_windows
|> Enum.group_by(&elem(&1, 1), &elem(&1, 0))
|> Enum.map(fn {index, value} ->
offset = weighted_offset(output_weighted_shape, index)
{offset, Enum.reduce(value, init_value, scatter_fn)}
end)
|> Enum.sort_by(&elem(&1, 0))
init_binary = number_to_binary(init_value, output_type)
{final_offset, unpadded_output_data} =
for {offset, value} <- values_with_indices, reduce: {0, <<>>} do
{acc_offset, acc_binary} ->
num_vals_before = div(offset - acc_offset, output_size)
vals_before = List.duplicate(init_binary, num_vals_before)
source_val = to_binary(value)
new_binary = IO.iodata_to_binary([vals_before, source_val])
{offset + output_size,
<<acc_binary::size(acc_offset)-bitstring, new_binary::bitstring>>}
end
num_vals_left = div(output_size * Nx.size(output_shape) - final_offset, output_size)
vals_left = IO.iodata_to_binary(List.duplicate(init_binary, num_vals_left))
output_data = <<unpadded_output_data::size(final_offset)-bitstring, vals_left::bitstring>>
from_binary(out, output_data)
end
defp flattened_index_to_offset(leftover, [dim | []], _, acc),
do: Enum.reverse([rem(leftover, dim) | acc])
defp flattened_index_to_offset(leftover, [dim | rest], n, acc) do
if leftover < Nx.size(List.to_tuple(rest)) do
flattened_index_to_offset(leftover, rest, 0, [n | acc])
else
flattened_index_to_offset(
leftover - Nx.size(List.to_tuple(rest)),
[dim | rest],
n + 1,
acc
)
end
end
@impl true
def indexed_add(out, target, indices, updates) do
resolve_updates = fn upds -> Enum.reduce(upds, 0, &+/2) end
update_element = &+/2
indexed_op(out, target, indices, updates, resolve_updates, update_element)
end
@impl true
def indexed_put(out, target, indices, updates) do
resolve_updates = fn upds -> Enum.at(upds, -1) end
update_element = fn _cur, upd -> upd end
indexed_op(out, target, indices, updates, resolve_updates, update_element)
end
defp indexed_op(
%T{} = out,
%T{shape: shape, type: {_, target_size}} = target,
%T{shape: {indices_rows, _indices_cols} = indices_shape} = indices,
%T{shape: {indices_rows}} = updates,
resolve_updates,
update_element
) do
indices_bin_list =
indices |> to_binary() |> aggregate_axes([1], indices_shape, elem(indices.type, 1))
offsets_list =
for idx_bin <- indices_bin_list do
idx = binary_to_list(idx_bin, indices.type)
offset = index_to_binary_offset(idx, shape)
offset * target_size
end
updates_list = binary_to_list(to_binary(updates), updates.type)
{offsets_with_updates, _last_offset} =
offsets_list
|> Enum.zip(updates_list)
|> Enum.group_by(fn {off, _} -> off end, fn {_, upd} -> upd end)
|> Enum.sort_by(fn {off, _} -> off end)
|> Enum.map_reduce(0, fn {next_offset, upds}, previous_offset ->
{{
previous_offset + target_size,
next_offset,
resolve_updates.(upds)
}, next_offset}
end)
target_binary = to_binary(target)
offsets_with_updates =
List.update_at(offsets_with_updates, 0, fn {_prev, current, update} ->
{0, current, update}
end)
{result, tail} =
for {previous, current, update} <- offsets_with_updates, reduce: {<<>>, target_binary} do
{traversed, to_traverse} ->
before_slice_size = current - previous
{before_offset, updated_element, to_traverse} =
match_types [target.type, out.type] do
<<before_offset::bitstring-size(before_slice_size), match!(element, 0),
to_traverse::bitstring>> = to_traverse
updated_element = <<write!(update_element.(read!(element, 0), update), 1)>>
{before_offset, updated_element, to_traverse}
end
# this can be a list of binaries because we are accumulation an iodata list
before_offset =
if target.type == out.type do
before_offset
else
binary_to_binary(before_offset, target.type, out.type, & &1)
end
{[traversed, before_offset | updated_element], to_traverse}
end
# this can be a list of binaries because we are accumulation an iodata list
tail =
if target.type == out.type do
tail
else
binary_to_binary(tail, target.type, out.type, & &1)
end
from_binary(out, IO.iodata_to_binary([result, tail]))
end
@impl true
def clip(out, tensor, min, max) do
in_data = to_binary(tensor)
min = binary_to_number(to_binary(min), min.type)
max = binary_to_number(to_binary(max), max.type)
out_data = binary_to_binary(in_data, tensor.type, out.type, &min(max(&1, min), max))
from_binary(out, out_data)
end
@impl true
def slice(out, tensor, start_indices, lengths, strides) do
# If you think of a slice as drawing a bounding box in the dimensions
# of the tensor, then it's clear we can simply use a weighted
# traversal to construct the new tensor
%T{type: {_, size}, shape: shape} = tensor
%{shape: output_shape} = out
tensor
|> to_binary()
|> bin_slice(shape, size, start_indices, lengths, strides, output_shape)
|> then(&from_binary(out, &1))
end
defp bin_slice(data, shape, size, start_indices, lengths, strides, output_shape) do
start_indices = clamp_indices(start_indices, shape, lengths)
if hd(strides) == 1 and top_dimension_slice?(tuple_size(shape), shape, output_shape) do
length = Nx.size(output_shape) * div(size, 8)
offset = div(length, elem(output_shape, 0)) * hd(start_indices)
binary_part(data, offset, length)
else
# Anchored around the start indices
weighted_shape = weighted_shape(shape, size, output_shape)
offset = weighted_offset(weighted_shape, start_indices)
# The weighted shape is altered such that we traverse
# with respect to the stride for each dimension
weighted_shape =
Enum.zip_with(weighted_shape, strides, fn {d, dim_size}, s ->
{d, dim_size + (s - 1) * dim_size}
end)
IO.iodata_to_binary(weighted_traverse(weighted_shape, data, size, offset))
end
end
defp clamp_indices(start_indices, shape, lengths) do
Enum.zip_with([Tuple.to_list(shape), start_indices, lengths], fn [dim_size, idx, len] ->
idx = scalar_to_number(idx)
min(max(idx, 0), dim_size - len)
end)
end
defp top_dimension_slice?(1, _, _), do: true
defp top_dimension_slice?(i, is, os)
when :erlang.element(i, is) == :erlang.element(i, os),
do: top_dimension_slice?(i - 1, is, os)
defp top_dimension_slice?(_, _, _), do: false
@impl true
def put_slice(out, tensor, start_indices, slice, combine_fn \\ fn _prev, new -> new end) do
%T{type: {_, size} = type, shape: shape} = tensor = as_type(out, tensor)
%T{shape: slice_shape} = slice = as_type(%{slice | type: type}, slice)
start_indices = clamp_indices(start_indices, shape, Tuple.to_list(slice_shape))
weighted_shape = weighted_shape(shape, size)
rank = Nx.rank(shape)
ones = List.duplicate(1, rank)
offsets =
slice_shape
|> make_anchors(ones, List.to_tuple(ones))
|> Enum.map(fn index ->
pos =
index
|> Enum.zip(start_indices)
|> Enum.map(fn {x, s} -> x + s end)
weighted_offset(weighted_shape, pos)
end)
|> Enum.sort()
{_, data} =
for offset <- offsets, reduce: {to_binary(slice), to_binary(tensor)} do
{<<cur_elem::size(size)-bitstring, rest_of_slice::bitstring>>, binary} ->
<<before::size(offset)-bitstring, prev_elem::size(size)-bitstring,
rest_of_tensor::bitstring>> = binary
new_elem = combine_fn.(prev_elem, cur_elem)
{rest_of_slice,
<<before::size(offset)-bitstring, new_elem::size(size)-bitstring,
rest_of_tensor::bitstring>>}
end
from_binary(out, data)
end
@impl true
def take(out, tensor, indices, axis) do
# We iterate over the indices in a flat manner,
# and take a unit tensor slice along axis given
# by each index. Then we concatenate the tensors
# along the axis, which gives us the result with
# index dimensions flattened and we just reshape.
%T{type: {_, size}, shape: shape} = tensor
%T{type: {_, idx_size}} = indices
data = to_binary(tensor)
tensor_rank = tuple_size(shape)
slice_start = List.duplicate(0, tensor_rank)
slice_lengths = shape |> Tuple.to_list() |> List.replace_at(axis, 1)
slice_shape = List.to_tuple(slice_lengths)
strides = List.duplicate(1, tensor_rank)
slices =
for <<bin::size(idx_size)-bitstring <- to_binary(indices)>> do
idx = binary_to_number(bin, indices.type)
if idx < 0 or idx >= elem(shape, axis) do
raise ArgumentError,
"index #{idx} is out of bounds for axis #{axis} in shape #{inspect(shape)}"
end
slice_start = List.replace_at(slice_start, axis, idx)
slice_data =
bin_slice(data, shape, size, slice_start, slice_lengths, strides, slice_shape)
{slice_data, slice_shape}
end
concat_shape = put_elem(tensor.shape, axis, length(slices))
result_data = bin_concatenate(slices, size, axis, concat_shape)
from_binary(out, result_data)
end
@impl true
def take_along_axis(
%T{type: output_type} = output,
%T{shape: t_shape, type: {_, t_size} = t_type} = tensor,
%T{shape: idx_shape, type: {_, idx_size} = idx_type} = indices,
axis
) do
permutation =
tensor
|> Nx.axes()
|> List.delete(axis)
|> List.insert_at(Nx.rank(tensor) - 1, axis)
inverse_permutation =
permutation
|> Enum.with_index()
|> Enum.sort_by(fn {x, _} -> x end)
|> Enum.map(fn {_, i} -> i end)
shape_list = Tuple.to_list(output.shape)
permuted_shape = permutation |> Enum.map(&Enum.at(shape_list, &1)) |> List.to_tuple()
t_view = tensor |> to_binary() |> aggregate_axes([axis], t_shape, t_size)
idx_view = indices |> to_binary() |> aggregate_axes([axis], idx_shape, idx_size)
[t_view, idx_view]
|> Enum.zip_with(fn [data_bin, idx_bin] ->
data = binary_to_list(data_bin, t_type)
binary_to_binary(idx_bin, idx_type, output_type, fn idx ->
if idx < 0 or idx >= elem(tensor.shape, axis) do
raise ArgumentError,
"index #{idx} is out of bounds for axis #{axis} in shape #{inspect(tensor.shape)}"
end
Enum.at(data, idx)
end)
end)
|> then(&from_binary(%{output | shape: permuted_shape}, &1))
|> then(&transpose(output, &1, inverse_permutation))
end
@impl true
def gather(out, tensor, indices) do
%T{type: {_, size}, shape: shape} = tensor
%T{type: {_, idx_size}} = indices
data = to_binary(tensor)
rank = tuple_size(shape)
byte_size = div(size, 8)
idx_last_dim_bin_size = rank * idx_size
new_data =
for <<bin::size(idx_last_dim_bin_size)-bitstring <- to_binary(indices)>>, into: <<>> do
slice_start =
for <<bin::size(idx_size)-bitstring <- bin>>, do: binary_to_number(bin, indices.type)
offset = index_to_binary_offset(slice_start, shape)
binary_part(data, offset * byte_size, byte_size)
end
from_binary(out, new_data)
end
defp index_to_binary_offset(index, input_shape) when is_list(index) and is_tuple(input_shape) do
{offset, []} =
index
|> Enum.with_index()
|> Enum.reduce(
{0, Tuple.to_list(input_shape)},
fn {idx, axis}, {offset, [dim_size | shape]} ->
if idx < 0 or idx >= dim_size do
raise ArgumentError,
"index #{idx} is out of bounds for axis #{axis} in shape #{inspect(input_shape)}"
end
{offset + idx * Enum.product(shape), shape}
end
)
offset
end
@impl true
def concatenate(out, tensors, axis) do
%{shape: output_shape, type: {_, size} = output_type} = out
tensors
|> Enum.map(fn %{shape: shape} = t ->
t = as_type(%{t | type: output_type}, t)
{to_binary(t), shape}
end)
|> bin_concatenate(size, axis, output_shape)
|> then(&from_binary(out, &1))
end
defp bin_concatenate(binaries_with_shape, _size, 0, _output_shape) do
binaries_with_shape |> Enum.map(&elem(&1, 0)) |> IO.iodata_to_binary()
end
defp bin_concatenate(binaries_with_shape, size, axis, output_shape) do
rank = tuple_size(output_shape)
steps = product_part(output_shape, 0, axis)
data =
for step <- 1..steps,
{binary, shape} <- binaries_with_shape do
product = product_part(shape, axis, rank) * size
before = (step - 1) * product
<<_::bitstring-size(before), part::bitstring-size(product), _::bitstring>> = binary
part
end
IO.iodata_to_binary(data)
end
defp product_part(_tuple, n, n), do: 1
defp product_part(tuple, n, limit), do: elem(tuple, n) * product_part(tuple, n + 1, limit)
@impl true
def as_type(out, tensor) do
%{type: output_type} = out
case tensor do
%T{type: ^output_type} ->
tensor
%T{type: input_type} ->
float_output? = Nx.Type.float?(output_type)
real_output? = not Nx.Type.complex?(output_type)
data = to_binary(tensor)
output_data =
match_types [input_type] do
for <<match!(x, 0) <- data>>, into: <<>> do
x = read!(x, 0)
case x do
%Complex{re: re} when float_output? and real_output? ->
number_to_binary(re, output_type)
_ when float_output? ->
number_to_binary(x, output_type)
%Complex{re: re} ->
number_to_binary(trunc(re), output_type)
_ when is_number(x) ->
number_to_binary(trunc(x), output_type)
:nan ->
number_to_binary(0, output_type)
:infinity ->
Nx.Type.max_finite_binary(output_type)
:neg_infinity ->
Nx.Type.min_finite_binary(output_type)
end
end
end
from_binary(out, output_data)
end
end
@impl true
def bitcast(out, tensor), do: from_binary(out, to_binary(tensor))
@impl true
def sort(output, t, opts), do: do_sort(output, t, opts, false)
@impl true
def argsort(output, t, opts), do: do_sort(output, t, opts, true)
defp do_sort(output, t, opts, return_indices) do
%T{shape: shape, type: type} = t
last_axis = Nx.rank(t) - 1
axis = opts[:axis]
comparator =
case opts[:direction] do
:desc ->
fn a, b ->
a = binary_to_number(a, type)
b = binary_to_number(b, type)
a >= b
end
:asc ->
fn a, b ->
a = binary_to_number(a, type)
b = binary_to_number(b, type)
a <= b
end
end
case shape do
{} when return_indices ->
sort_last_dim(t, comparator, output, return_indices)
{} ->
t
_ when axis == last_axis ->
sort_last_dim(t, comparator, output, return_indices)
_ ->
permutation = Nx.axes(t)
permutation =
permutation
|> List.delete(axis)
|> List.insert_at(Nx.rank(t) - 1, axis)
inverse_permutation =
permutation
|> Enum.with_index()
|> Enum.sort_by(fn {x, _} -> x end)
|> Enum.map(fn {_, i} -> i end)
permuted_t = Nx.transpose(t, axes: permutation)
permuted_t
|> sort_last_dim(comparator, %{permuted_t | type: output.type}, return_indices)
|> Nx.transpose(axes: inverse_permutation)
end
end
defp sort_last_dim(
%T{shape: shape, type: {_, size}} = t,
comparator,
output,
return_indices
) do
view = aggregate_axes(to_binary(t), [tuple_size(shape) - 1], shape, size)
new_data =
for bin <- view, into: <<>> do
data = for <<x::size(size)-bitstring <- bin>>, do: x
sorted =
if return_indices do
data
|> Enum.with_index()
|> Enum.sort_by(&elem(&1, 0), comparator)
|> Enum.map(fn {_, index} -> number_to_binary(index, output.type) end)
else
Enum.sort(data, comparator)
end
IO.iodata_to_binary(sorted)
end
from_binary(output, new_data)
end
@impl true
def fft(out, tensor, opts), do: calculate_fft(out, tensor, opts, :fft)
@impl true
def ifft(out, tensor, opts), do: calculate_fft(out, tensor, opts, :ifft)
defp calculate_fft(out, %{shape: shape, type: {_, size}} = tensor, opts, kind) do
eps = opts[:eps]
n = opts[:length]
input_view = aggregate_axes(to_binary(tensor), [tuple_size(shape) - 1], shape, size)
[row | _] =
input_data =
for row <- input_view do
binary_to_list(row, tensor.type)
end
len_data = length(row)
data =
for row <- input_data do
cond do
len_data < n -> row ++ List.duplicate(0, n - len_data)
len_data > n -> Enum.take(row, n)
true -> row
end
end
result =
for row <- data do
case kind do
:fft ->
fft_list(row, n)
:ifft ->
row
|> Enum.map(&Complex.conjugate/1)
|> fft_list(n)
|> Enum.map(&(Complex.conjugate(&1) / n))
end
end
output_data =
match_types [out.type] do
for row <- result, %Complex{re: re, im: im} <- row, into: <<>> do
re = if abs(re) <= eps, do: 0, else: re
im = if abs(im) <= eps, do: 0, else: im
<<write!(Complex.new(re, im), 0)>>
end
end
from_binary(out, output_data)
end
defp fft_list(data, bigN) when bigN < 2, do: data
defp fft_list(data, bigN) when rem(bigN, 2) != 0 do
# Naive DFT case for when bigN is odd > 2
for k <- 0..(bigN - 1) do
minus_two_pi_k_over_bigN = -2 * :math.pi() * k / bigN
data
|> Enum.with_index(fn x, n ->
x * Complex.exp(Complex.new(0, minus_two_pi_k_over_bigN * n))
end)
|> Enum.reduce(&+/2)
end
end
defp fft_list([_ | tail] = data, bigN) do
# Here bigN is guaranteed to be even, so the recursion will
# work on at least one level
bigN_over_2 = div(bigN, 2)
even = fft_list(Enum.take_every(data, 2), bigN_over_2)
odd = fft_list(Enum.take_every(tail, 2), bigN_over_2)
t =
Enum.with_index(odd, fn item, k ->
Complex.exp(Complex.new(0, -2 * :math.pi() * k / bigN)) * item
end)
left = Enum.zip_with([even, t], fn [x, y] -> x + y end)
right = Enum.zip_with([even, t], fn [x, y] -> x - y end)
left ++ right
end
## Binary reducers
defp bin_reduce(tensor, type, acc, opts, fun) do
%T{type: {_, size}, shape: shape} = tensor
view =
if axes = opts[:axes] do
aggregate_axes(to_binary(tensor), axes, shape, size)
else
[to_binary(tensor)]
end
for axis <- view, into: <<>> do
{result, _} =
for <<bin::size(size)-bitstring <- axis>>, reduce: {<<>>, acc} do
{_, acc} -> fun.(bin, acc)
end
scalar_to_binary!(result, type)
end
end
defp bin_zip_reduce(t1, [], t2, [], type, acc, fun) do
%{type: {_, s1}} = t1
%{type: {_, s2}} = t2
b1 = to_binary(t1)
b2 = to_binary(t2)
match_types [t1.type, t2.type] do
for <<d1::size(s1)-bitstring <- b1>>, <<d2::size(s2)-bitstring <- b2>>, into: <<>> do
{result, _} = fun.(d1, d2, acc)
scalar_to_binary!(result, type)
end
end
end
defp bin_zip_reduce(t1, [_ | _] = axes1, t2, [_ | _] = axes2, type, acc, fun) do
{_, s1} = t1.type
{_, s2} = t2.type
v1 = aggregate_axes(to_binary(t1), axes1, t1.shape, s1)
v2 = aggregate_axes(to_binary(t2), axes2, t2.shape, s2)
for b1 <- v1, b2 <- v2 do
{bin, _acc} = bin_zip_reduce_axis(b1, b2, s1, s2, <<>>, acc, fun)
scalar_to_binary!(bin, type)
end
end
# Helper for reducing down a single axis over two tensors,
# returning tensor data and a final accumulator.
defp bin_zip_reduce_axis(<<>>, <<>>, _s1, _s2, bin, acc, _fun),
do: {bin, acc}
defp bin_zip_reduce_axis(b1, b2, s1, s2, _bin, acc, fun) do
<<x::size(s1)-bitstring, rest1::bitstring>> = b1
<<y::size(s2)-bitstring, rest2::bitstring>> = b2
{bin, acc} = fun.(x, y, acc)
bin_zip_reduce_axis(rest1, rest2, s1, s2, bin, acc, fun)
end
defp bin_batch_reduce(bin, batch_size, {_, size}, acc, fun) do
batch_byte_size = (batch_size * size) |> div(8)
batches = byte_size(bin) |> div(batch_byte_size)
for i <- 0..(batches - 1), reduce: acc do
acc ->
batch = binary_part(bin, i * batch_byte_size, batch_byte_size)
fun.(batch, acc)
end
end
## Conversion helpers
defp scalar_to_number(n) when is_number(n) or n in [:nan, :neg_infinity, :infinity], do: n
defp scalar_to_number(%Complex{} = n), do: n
defp scalar_to_number(t), do: binary_to_number(to_binary(t), t.type)
defp scalar_to_binary!(%Complex{re: re, im: im}, type) do
real_type = Nx.Type.to_real(type)
number_to_binary(re, real_type) <> number_to_binary(im, real_type)
end
defp scalar_to_binary!(value, type)
when is_number(value) or value in [:nan, :neg_infinity, :infinity],
do: number_to_binary(value, type)
defp scalar_to_binary!(%T{shape: {}, type: type} = t, type),
do: to_binary(t)
defp scalar_to_binary!(t, type) do
raise ArgumentError,
"expected a number or a scalar tensor of type #{inspect(type)}, got: #{inspect(t)}"
end
defp number_to_binary(number, type),
do: match_types([type], do: <<write!(number, 0)>>)
defp binary_to_number(bin, type) do
match_types [type] do
<<match!(value, 0)>> = bin
read!(value, 0)
end
end
defp binary_to_list(binary, type) do
match_types [type] do
for <<match!(x, 0) <- binary>>, do: read!(x, 0)
end
end
defp binary_to_binary(binary, in_type, out_type, fun) do
match_types [in_type, out_type] do
for <<match!(seg, 0) <- binary>>, into: <<>> do
<<write!(fun.(read!(seg, 0)), 1)>>
end
end
end
## Aggregation helpers
defp aggregate_axes(binary, axes, shape, size) do
{chunk_size, read_size, path} = aggregate_axes(axes, shape, size)
view =
for <<chunk::size(chunk_size)-bitstring <- binary>> do
weighted_traverse(path, chunk, read_size)
end
List.flatten(view)
end
defp aggregate_axes([_ | _] = axes, shape, size) do
axes = Enum.sort(axes)
min = hd(axes)
weighted_shape = weighted_shape(shape, size)
[{axis_count, axis_weight} | _] = weighted_shape = Enum.drop(weighted_shape, min)
chunk_size = axis_count * axis_weight
# The goal of aggregate path is to split the paths
# we are reducing from the ones we are keeping as is.
{reverse_pre, reverse_pos} = aggregate_path(weighted_shape, axes, min, [], [])
# Now if we are reducing on the last dimensions, we
# can increase the read size.
{reverse_pos, read_size} =
aggregate_read(reverse_pos, tuple_size(shape) - 1, Enum.reverse(axes), size)
path = Enum.reverse(reverse_pre, [(&IO.iodata_to_binary/1) | Enum.reverse(reverse_pos)])
{chunk_size, read_size, path}
end
defp aggregate_path([pair | shape], [i | axes], i, pre, pos),
do: aggregate_path(shape, axes, i + 1, pre, [pair | pos])
defp aggregate_path([pair | shape], axes, i, pre, pos),
do: aggregate_path(shape, axes, i + 1, [pair | pre], pos)
defp aggregate_path([], [], _i, pre, pos), do: {pre, pos}
defp aggregate_read([{axis, weight} | shape], i, [i | axis], _size),
do: aggregate_read(shape, i - 1, axis, axis * weight)
defp aggregate_read(shape, _i, _axis, size),
do: {shape, size}
## Weighted shapes
# Converts the shape to a weight shape list.
#
# A weighted shape is a list of tuples where the first
# element is the number of elements in the dimension
# and the second element is the size to be traversed in
# the binary to fetch the next element.
#
# This is often given to `weighted_traverse/4` as a general
# mechanism to traverse binaries.
defp weighted_shape(shape, size, limits \\ :none, dilations \\ 1) do
rank = tuple_size(shape)
dilations =
if is_list(dilations),
do: Enum.reverse(dilations),
else: List.duplicate(dilations, rank)
weighted_shape(shape, rank, size, limits, dilations, [])
end
defp weighted_shape(_shape, 0, _weight, _limits, [], acc), do: acc
defp weighted_shape(shape, pos, weight, limits, [dilation | dilations], acc) do
shape_elem = :erlang.element(pos, shape)
element =
if limits == :none, do: shape_elem, else: min(:erlang.element(pos, limits), shape_elem)
dilation_factor =
if element == 1,
do: 1,
else: dilation
acc = [{element, dilation_factor * weight} | acc]
weighted_shape(shape, pos - 1, weight * shape_elem, limits, dilations, acc)
end
# Reads the chunk size from a weighted list at the given position.
defp weighted_chunk(list, at, size) do
{element, size} = Enum.at(list, at, {1, size})
element * size
end
# Traverses a binary using the elements and shape given by `weighted_shape`.
#
# When all dimensions are traversed, we read `read_size`.
#
# The `weighted_shape` can also contain functions, which are applied to the
# result of the remaining of the weighted shape.
defp weighted_traverse(weighted_shape, binary, read_size, offset \\ 0)
defp weighted_traverse([], data, read_size, offset) do
<<_::size(offset)-bitstring, chunk::size(read_size)-bitstring, _::bitstring>> = data
chunk
end
defp weighted_traverse([{dim, size} | dims], data, read_size, offset) do
weighted_traverse(dim, size, dims, data, read_size, offset)
end
defp weighted_traverse([fun | dims], data, read_size, offset) do
fun.(weighted_traverse(dims, data, read_size, offset))
end
defp weighted_traverse(dim, dim_size, dims, data, read_size, offset) do
head = weighted_traverse(dims, data, read_size, offset)
case dim do
1 ->
[head]
_ ->
<<_::size(dim_size)-bitstring, data::bitstring>> = data
[head | weighted_traverse(dim - 1, dim_size, dims, data, read_size, offset)]
end
end
# Makes anchors for traversing a binary with a window.
defp make_anchors(shape, strides, window, dilations \\ 1)
defp make_anchors(shape, strides, window, dilations)
when is_tuple(shape) and is_tuple(window) and is_list(strides) do
dilations =
if is_integer(dilations),
do: List.duplicate(dilations, tuple_size(shape)),
else: dilations
make_anchors(Tuple.to_list(shape), strides, Tuple.to_list(window), dilations, :init)
end
defp make_anchors([], [], _window, _dilations, anchors), do: anchors
defp make_anchors([dim | shape], [s | strides], [w | window], [dil | dilation], :init) do
dims = for i <- 0..(dim - 1), rem(i, s) == 0 and i + (w - 1) * dil < dim, do: [i]
make_anchors(shape, strides, window, dilation, dims)
end
defp make_anchors([dim | shape], [s | strides], [w | window], [dil | dilation], anchors) do
anchors =
for i <- 0..(dim - 1),
rem(i, s) == 0 and i + (w - 1) * dil < dim,
anchor <- anchors,
do: anchor ++ [i]
make_anchors(shape, strides, window, dilation, anchors)
end
# Calculates the offset needed to reach a specified position
# in the binary from a weighted shape list.
defp weighted_offset(weighted_shape, pos, dilations \\ 1)
defp weighted_offset(weighted_shape, pos, dilations) when is_list(pos) do
dilations =
if is_list(dilations),
do: dilations,
else: List.duplicate(dilations, length(weighted_shape))
sum_weighted_offset(weighted_shape, pos, dilations)
end
defp sum_weighted_offset([], [], []), do: 0
defp sum_weighted_offset([{s, size} | dims], [x | pos], [d | dilation]) do
# Account for the dilation
dilation_factor =
if s == 1,
do: 1,
else: d
div(size, dilation_factor) * x + weighted_offset(dims, pos, dilation)
end
end
