Abdelrahman Said
104 lines
2.8 KiB
C
104 lines
2.8 KiB
C
/*
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igraph library.
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Copyright (C) 2021-2022 The igraph development team <igraph@igraph.org>
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>.
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*/
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#include <igraph.h>
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#include "test_utilities.h"
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/* Matrix-vector multiplication: y = A.x */
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void matmul(const igraph_matrix_t *A, const igraph_vector_t *x, igraph_vector_t *y, igraph_real_t beta) {
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igraph_int_t i, j, nr = igraph_matrix_nrow(A), nc = igraph_matrix_ncol(A);
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IGRAPH_ASSERT(nc == igraph_vector_size(x));
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IGRAPH_ASSERT(nr == igraph_vector_size(y));
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igraph_vector_scale(y, beta);
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for (i=0; i < nr; ++i) {
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for (j=0; j < nc; ++j) {
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VECTOR(*y)[i] += MATRIX(*A, i, j) * VECTOR(*x)[j];
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}
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}
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}
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int main(void) {
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igraph_matrix_t A;
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igraph_vector_t x, y1, y2;
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igraph_int_t i, j;
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const igraph_int_t nr = 5, nc = 8;
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igraph_rng_seed(igraph_rng_default(), 54632);
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igraph_matrix_init(&A, nr, nc);
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igraph_vector_init(&x, nc);
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/* Fill with arbitrary values. Should be zeroes by beta. */
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igraph_vector_init_range(&y1, 1, nr + 1);
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igraph_vector_init_copy(&y2, &y1);
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for (i=0; i < nr; ++i) {
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for (j=0; j < nc; ++j) {
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MATRIX(A, i, j) = (igraph_real_t) RNG_INTEGER(-10, 10);
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}
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}
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for (j=0; j < nc; ++j) {
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VECTOR(x)[j] = (igraph_real_t) RNG_INTEGER(-10, 10);
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}
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printf("Input matrix A:\n");
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print_matrix(&A);
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printf("\nInput vector x:\n");
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print_vector(&x);
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igraph_blas_dgemv(0, 1, &A, &x, 0, &y1);
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matmul(&A, &x, &y2, 0);
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printf("\nResult vector DGEMV:\n");
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print_vector(&y1);
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printf("\nResult vector naive:\n");
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print_vector(&y2);
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/* Results should be exact since all values are integers */
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IGRAPH_ASSERT(igraph_vector_all_e(&y1, &y2));
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printf("\nAdding to previous result with beta=2:\n");
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igraph_blas_dgemv(0, 1, &A, &x, 2, &y1);
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matmul(&A, &x, &y2, 2);
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printf("\nResult vector DGEMV:\n");
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print_vector(&y1);
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printf("\nResult vector naive:\n");
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print_vector(&y2);
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IGRAPH_ASSERT(igraph_vector_all_e(&y1, &y2));
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igraph_vector_destroy(&y2);
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igraph_vector_destroy(&y1);
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igraph_vector_destroy(&x);
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igraph_matrix_destroy(&A);
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VERIFY_FINALLY_STACK();
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return 0;
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}
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