mlx/examples/extensions/axpby/axpby.h
2023-11-30 11:12:53 -08:00

86 lines
2.5 KiB
C++

// Copyright © 2023 Apple Inc.
#pragma once
#include "mlx/ops.h"
#include "mlx/primitives.h"
namespace mlx::core {
///////////////////////////////////////////////////////////////////////////////
// Operation
///////////////////////////////////////////////////////////////////////////////
/**
* Scale and sum two vectors elementwise
* z = alpha * x + beta * y
*
* Follow numpy style broadcasting between x and y
* Inputs are upcasted to floats if needed
**/
array axpby(
const array& x, // Input array x
const array& y, // Input array y
const float alpha, // Scaling factor for x
const float beta, // Scaling factor for y
StreamOrDevice s = {} // Stream on which to schedule the operation
);
///////////////////////////////////////////////////////////////////////////////
// Primitive
///////////////////////////////////////////////////////////////////////////////
class Axpby : public Primitive {
public:
explicit Axpby(Stream stream, float alpha, float beta)
: Primitive(stream), alpha_(alpha), beta_(beta){};
/**
* A primitive must know how to evaluate itself on the CPU/GPU
* for the given inputs and populate the output array.
*
* To avoid unecessary allocations, the evaluation function
* is responsible for allocating space for the array.
*/
void eval_cpu(const std::vector<array>& inputs, array& out) override;
void eval_gpu(const std::vector<array>& inputs, array& out) override;
/** The Jacobian-vector product. */
array jvp(
const std::vector<array>& primals,
const std::vector<array>& tangents,
const std::vector<int>& argnums) override;
/** The vector-Jacobian product. */
std::vector<array> vjp(
const std::vector<array>& primals,
const array& cotan,
const std::vector<int>& argnums) override;
/**
* The primitive must know how to vectorize itself accross
* the given axes. The output is a pair containing the array
* representing the vectorized computation and the axis which
* corresponds to the output vectorized dimension.
*/
std::pair<array, int> vmap(
const std::vector<array>& inputs,
const std::vector<int>& axes) override;
/** Print the primitive. */
void print(std::ostream& os) override {
os << "Axpby";
}
/** Equivalence check **/
bool is_equivalent(const Primitive& other) const override;
private:
float alpha_;
float beta_;
/** Fall back implementation for evaluation on CPU */
void eval(const std::vector<array>& inputs, array& out);
};
} // namespace mlx::core