Struct autograd::op::ComputeContext

pub struct ComputeContext<'t, 'v, T: Float> { /* fields omitted */ }

Context of an Op's computation phase.

Example

use autograd as ag;

// Implementing `Op` trait for `Sigmoid`.
struct Sigmoid;

impl<T: ag::Float> ag::op::Op<T> for Sigmoid {
    fn compute(
        &self,
        ctx: &mut ag::op::ComputeContext<T>,
    ) {
        // Getting the first input array.
        let x: &ag::NdArrayView<_> = &ctx.input(0);
        let half = T::from(0.5).unwrap();
        let y = x.mapv(move |a| ((a * half).tanh() * half) + half);
        // Put the computed result.
        ctx.append_output(y);
    }

    fn grad(&self, ctx: &mut ag::op::GradientContext<T>) { /* ... */ }
}

Implementations

impl<'g, 't, 'v, T: Float> ComputeContext<'t, 'v, T>

pub fn input(&mut self, i: usize) -> NdArrayView<'v, T>

Grabs the i th input array as a read-only array view.

Calling input(i) more than once causes panic.

pub fn input_mut(&mut self, i: usize) -> NdArrayViewMut<'v, T>

Grabs the i th input array as a read-write array view.

Calling input_mut(i) more than once causes panic.

pub fn append_output_view(&mut self, y: NdArrayView<'v, T>)

Appends an ndarray::ArrayView to the back of the output list of the current op.

NOTE: Implementor of Op::compute must not forget to call append_* as many as the number of its output in Op::compute, otherwise panic occurs.

pub fn append_output(&mut self, y: NdArray<T>)

Appends an ndarray to the back of the output list of the current op.

NOTE: Implementor of Op::compute must not forget to call append_* as many as the number of its output in Op::compute, otherwise panic occurs.

pub fn append_empty_output(&mut self)

Appends an empty result to the back of the output list of the current op.

For example, this is used for gradient-descent-optimizers.

NOTE: Implementor of Op::compute must not forget to call append_* as many as the number of its output in Op::compute, otherwise panic occurs.

pub fn set_error(&mut self, y: OpError)

Marks this op's compute session as failed.

NOTE: After called this function, Op::compute should return early.

pub fn num_inputs(&self) -> usize

Returns a number of input arrays.