Linear Algebra and the C Language/a06j

__NOTOC__ Install and compile this file in your working directory. /* ------------------------------------ */ /* Save as : c00b.c */ /* ------------------------------------ */ #include "v_a.h" /* ------------------------------------ */ #define RC RC3 #define Cb C1 /* ------------------------------------ */ int main(void) { double ta[RC*RC] ={ 4,2,3, 5,3,1, 8,2,2}; double tb[RC*Cb] ={ 3, 2, 1}; double **A = ca_A_mR(ta,i_mR(RC,RC)); double **b = ca_A_mR(tb,i_mR(RC,Cb)); double **InvA = inv_mR(A, i_mR(RC,RC)); double **X = mul_mR(InvA,b, i_mR(RC,Cb)); clrscrn(); printf(" We want to find X such as, \n\n"); printf(" AX = b \n\n"); printf(" If A is a square matrix and, \n\n"); printf(" If A has an inverse matrix, \n\n"); printf(" you can find X by this method\n\n"); printf(" X = inv(A) b \n\n\n"); printf(" To verify the result you can \n\n"); printf(" multiply the matrix A by X. \n\n"); printf(" You must refind b. \n\n"); stop(); clrscrn(); printf(" A:"); p_mR(A, S5,P0,C7); printf(" b:"); p_mR(b, S5,P0,C7); stop(); clrscrn(); printf(" inv(A):"); pE_mR(InvA, S1,P3,C7); printf(" X = inv(A) b"); p_mR(X, S13,P4,C7); stop(); clrscrn(); printf(" b:"); p_mR(b, S5,P0,C7); printf(" AX:"); p_mR(mul_mR(A,X,b), S5,P0,C7); stop(); f_mR(X); f_mR(b); f_mR(InvA); f_mR(A); return 0; } /* ------------------------------------ */ /* ------------------------------------ */ Screen output example: We want to find X such as, AX = B If A is a square matrix and, If A has an inverse matrix, you can find X by this method X = inv(A) B To verify the result you can multiply the matrix A by X. You must refind B. Press return to continue. A : +4 +2 +3 +5 +3 +1 +8 +2 +2 B : +3 +2 +1 Press return to continue. inv(A) : -1.333e-01 -6.667e-02 +2.333e-01 +6.667e-02 +5.333e-01 -3.667e-01 +4.667e-01 -2.667e-01 -6.667e-02 X = inv(A) * B : -0.3000 +0.9000 +0.8000 Press return to continue. B : +3 +2 +1 AX : +3 +2 +1 Press return to continue.