use crate::autograd::util::reduce_gradient;
use crate::gradient_function::{GradientFuncTrait, GradientFunction};
use crate::{call_next_backward, FloatDataType, NdArray, StridedMemory, Tensor};
use std::cell::RefCell;
use std::rc::Rc;
pub(crate) struct MulBackwards<T: FloatDataType> {
next_functions: [GradientFunction<T>; 2],
lhs: Rc<NdArray<'static, T>>,
rhs: Rc<NdArray<'static, T>>,
}
pub(crate) struct MulScalarBackwards<T: FloatDataType> {
next_function: GradientFunction<T>,
shape: Vec<usize>,
scalar: T,
}
impl<T: FloatDataType> GradientFuncTrait<T> for MulBackwards<T> {
fn backward(&mut self, grad: &NdArray<T>) {
call_next_backward!(self.rhs.as_ref() * grad,
self.lhs.shape(), self.next_functions[0]);
call_next_backward!(self.lhs.as_ref() *
grad, self.rhs.shape(), self.next_functions[1]);
}
}
impl<T: FloatDataType> GradientFuncTrait<T> for MulScalarBackwards<T> {
fn backward(&mut self, grad: &NdArray<T>) {
call_next_backward!(grad * self.scalar,
&self.shape, self.next_function);
}
}
impl<T: FloatDataType> MulBackwards<T> {
pub(crate) fn new(lhs: &Tensor<T>, rhs: &Tensor<T>) -> GradientFunction<T> {
Rc::new(RefCell::new(Self {
next_functions: [lhs.grad_fn(), rhs.grad_fn()],
lhs: lhs.get_ndarray(),
rhs: rhs.get_ndarray(),
}))
}
}
impl<T: FloatDataType> MulScalarBackwards<T> {
pub(crate) fn new(lhs: &Tensor<T>, rhs: T) -> GradientFunction<T> {
Rc::new(RefCell::new(Self {
next_function: lhs.grad_fn(),
shape: lhs.shape().to_vec(),
scalar: rhs
}))
}
}