Atomic Matrix Multiply Reverse Dependency Analysis: Example Implementation

atomic_four_mat_mul_rev_depend.hpp

@(@\newcommand{\W}[1]{ \; #1 \; } \newcommand{\R}[1]{ {\rm #1} } \newcommand{\B}[1]{ {\bf #1} } \newcommand{\D}[2]{ \frac{\partial #1}{\partial #2} } \newcommand{\DD}[3]{ \frac{\partial^2 #1}{\partial #2 \partial #3} } \newcommand{\Dpow}[2]{ \frac{\partial^{#1}}{\partial {#2}^{#1}} } \newcommand{\dpow}[2]{ \frac{ {\rm d}^{#1}}{{\rm d}\, {#2}^{#1}} }@)@This is cppad-20221105 documentation. Here is a link to its current documentation . Atomic Matrix Multiply Reverse Dependency Analysis: Example Implementation
Purpose
The rev_depend routine is used by optimize to reduce the number of variables in the recording of a function.

Source


# include <cppad/example/atomic_four/mat_mul/mat_mul.hpp>

namespace CppAD { // BEGIN_CPPAD_NAMESPACE
//
// rev_depend override
template <class Base>
bool atomic_mat_mul<Base>::rev_depend(
    size_t                         call_id  ,
    CppAD::vector<bool>&           depend_x ,
    const CppAD::vector<bool>&     depend_y )
{
    //
    // n_left, n_middle, n_right
    size_t n_left, n_middle, n_right;
    get(call_id, n_left, n_middle, n_right);
# ifndef NDEBUG
    // n, m
    size_t n     = depend_x.size();
    size_t m     = depend_y.size();
    //
    // check sizes
    assert( n == n_left * n_middle + n_middle * n_right );
    assert( m == n_left * n_right );
# endif
    //
    // offset
    size_t offset = n_left * n_middle;
    //
    // type_y
    // y[ i * n_right + j] = sum_k
    //      x[i * n_middle + k] * x[ offset + k * n_right + j]
    // type_y
    for(size_t i = 0; i < n_left; ++i)
    {   for(size_t j = 0; j < n_right; ++j)
        {   size_t ij = i * n_right + j;
            if( depend_y[ij] )
            {   for(size_t k = 0; k < n_middle; ++k)
                {   size_t ik = i * n_middle + k;
                    size_t kj = offset + k * n_right + j;
                    depend_x[ik] = true;
                    depend_x[kj] = true;
                }
            }
        }
    }
    return true;
}
} // END_CPPAD_NAMESPACE

Input File: include/cppad/example/atomic_four/mat_mul/rev_depend.hpp