dynare/mex/sources/kronecker/A_times_B_kronecker_C.cc

115 lines
3.3 KiB
C++

/*
* Copyright © 2007-2020 Dynare Team
*
* This file is part of Dynare.
*
* Dynare is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Dynare is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Dynare. If not, see <http://www.gnu.org/licenses/>.
*/
/*
* This mex file computes A·(B⊗C) or A·(B⊗B) without explicitly building B⊗C or B⊗B, so that
* one can consider large matrices B and/or C.
*/
#include <dynmex.h>
#include <dynblas.h>
void
full_A_times_kronecker_B_C(const double *A, const double *B, const double *C, double *D,
blas_int mA, blas_int nA, blas_int mB, blas_int nB, blas_int mC, blas_int nC)
{
const blas_int shiftA = mA*mC;
const blas_int shiftD = mA*nC;
blas_int kd = 0, ka = 0;
double one = 1.0;
for (blas_int col = 0; col < nB; col++)
{
ka = 0;
for (blas_int row = 0; row < mB; row++)
{
dgemm("N", "N", &mA, &nC, &mC, &B[mB*col+row], &A[ka], &mA, C, &mC, &one, &D[kd], &mA);
ka += shiftA;
}
kd += shiftD;
}
}
void
full_A_times_kronecker_B_B(const double *A, const double *B, double *D, blas_int mA, blas_int nA, blas_int mB, blas_int nB)
{
const blas_int shiftA = mA*mB;
const blas_int shiftD = mA*nB;
blas_int kd = 0, ka = 0;
double one = 1.0;
for (blas_int col = 0; col < nB; col++)
{
ka = 0;
for (blas_int row = 0; row < mB; row++)
{
dgemm("N", "N", &mA, &nB, &mB, &B[mB*col+row], &A[ka], &mA, B, &mB, &one, &D[kd], &mA);
ka += shiftA;
}
kd += shiftD;
}
}
void
mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[])
{
// Check input and output:
if (nrhs > 3 || nrhs < 2 || nlhs != 1)
{
mexErrMsgTxt("A_times_B_kronecker_C takes 2 or 3 input arguments and provides 1 output argument.");
return; // Needed to shut up some GCC warnings
}
// Get & Check dimensions (columns and rows):
size_t mA = mxGetM(prhs[0]);
size_t nA = mxGetN(prhs[0]);
size_t mB = mxGetM(prhs[1]);
size_t nB = mxGetN(prhs[1]);
size_t mC, nC;
if (nrhs == 3) // A·(B⊗C) is to be computed.
{
mC = mxGetM(prhs[2]);
nC = mxGetN(prhs[2]);
if (mB*mC != nA)
mexErrMsgTxt("Input dimension error!");
}
else // A·(B⊗B) is to be computed.
{
if (mB*mB != nA)
mexErrMsgTxt("Input dimension error!");
}
// Get input matrices:
const double *A = mxGetPr(prhs[0]);
const double *B = mxGetPr(prhs[1]);
const double *C{nullptr};
if (nrhs == 3)
C = mxGetPr(prhs[2]);
// Initialization of the ouput:
if (nrhs == 3)
plhs[0] = mxCreateDoubleMatrix(mA, nB*nC, mxREAL);
else
plhs[0] = mxCreateDoubleMatrix(mA, nB*nB, mxREAL);
double *D = mxGetPr(plhs[0]);
// Computational part:
if (nrhs == 2)
full_A_times_kronecker_B_B(A, B, D, mA, nA, mB, nB);
else
full_A_times_kronecker_B_C(A, B, C, D, mA, nA, mB, nB, mC, nC);
}