rc_test_algebra.c

/**
 * @example    rc_test_algebra.c
 *
 * @brief      Tests the functions in rc_algebra.h
 *
 * @author     James Strawson
 * @date       1/29/2018
 */

#include <stdio.h>
#include <rc/math.h>

#define DIM 3

int main()
{
        rc_matrix_t A   = RC_MATRIX_INITIALIZER;
        rc_matrix_t Ainv= RC_MATRIX_INITIALIZER;
        rc_matrix_t AA  = RC_MATRIX_INITIALIZER;
        rc_matrix_t L   = RC_MATRIX_INITIALIZER;
        rc_matrix_t U   = RC_MATRIX_INITIALIZER;
        rc_matrix_t P   = RC_MATRIX_INITIALIZER;
        rc_matrix_t Q   = RC_MATRIX_INITIALIZER;
        rc_matrix_t R   = RC_MATRIX_INITIALIZER;
        rc_vector_t b   = RC_VECTOR_INITIALIZER;
        rc_vector_t x   = RC_VECTOR_INITIALIZER;
        rc_vector_t y   = RC_VECTOR_INITIALIZER;

        printf("Let's test some linear algebra functions....\n\n");


        // random matrix
        printf("\nNew Random Matrix A:\n");
        rc_matrix_random(&A,DIM,DIM);
        rc_matrix_print(A);

        // get an inverse for A
        printf("\nAinverse:\n");
        rc_algebra_invert_matrix(A,&Ainv);
        rc_matrix_print(Ainv);

        // multiply A times A inverse
        printf("\nA times A_inverse:\n");
        rc_matrix_multiply(A,Ainv,&AA);
        rc_matrix_print(AA);

        // invert A back again
        printf("\ninvert A again inplace\n");
        rc_algebra_invert_matrix_inplace(&Ainv);
        rc_matrix_print(Ainv);

        // do an LUP decomposition on A
        printf("\nLUP decomposition of A\n");
        rc_algebra_lup_decomp(A,&L,&U,&P);
        printf("L:\n");
        rc_matrix_print(L);
        printf("U:\n");
        rc_matrix_print(U);
        printf("P:\n");
        rc_matrix_print(P);

        // do a QR decomposition on A
        printf("\nQR Decomposition of A\n");
        rc_algebra_qr_decomp(A,&Q,&R);
        printf("Q:\n");
        rc_matrix_print(Q);
        printf("R:\n");
        rc_matrix_print(R);

        // solve a square linear system
        printf("\nGaussian Elimination solution x to the equation Ax=b:\n");
        printf("equivalent to A\\b in MATLAB\n");
        rc_vector_random(&b,DIM);
        rc_algebra_lin_system_solve(A,b,&x);
        rc_vector_print(x);

        // now do again but with qr decomposition method
        printf("\nQR solution x to the equation Ax=b:\n");
        printf("equivalent to A\\b in MATLAB\n");
        rc_algebra_lin_system_solve_qr(A,b,&y);
        rc_vector_print(y);

        // free memory
        rc_matrix_free(&A);
        rc_matrix_free(&Ainv);
        rc_matrix_free(&AA);
        rc_matrix_free(&L);
        rc_matrix_free(&U);
        rc_matrix_free(&P);
        rc_matrix_free(&Q);
        rc_matrix_free(&R);
        rc_vector_free(&b);
        rc_vector_free(&x);
        rc_vector_free(&y);
        printf("\nDONE\n");
        return 0;
}