Linear Algebra and the C Language/a0p1

__NOTOC__ Install and compile this file in your working directory. /* ------------------------------------ */ /* Save as : c00d.c */ /* ------------------------------------ */ #include "v_a.h" /* ------------------------------------ */ #define RCA RC2 /* ------------------------------------ */ /* ------------------------------------ */ int main(void) { double a[RCA*RCA] ={ +1.142857142857, +0.571428571428, -0.285714285714, -0.142857142857 }; double P[RCA*C1] ={ +3, +1 }; double **A = ca_A_mR(a, i_mR(RCA,RCA)); double **p = ca_A_mR(P, i_mR(RCA,C1)); double **Pp = i_mR(RCA,C1); clrscrn(); printf(" A :"); p_mR(A, S9,P12, C4); printf(" p: A point of the plan"); p_mR(p, S9,P12, C4); printf(" Pp: The projection of p on the line"); mul_mR(A,p,Pp); p_mR(Pp, S9,P12, C4); stop(); f_mR(A); f_mR(p); f_mR(Pp); return 0; } /* ------------------------------------ */ /* ------------------------------------ */ You can calculate the projection of a point P onto the line. You can draw a cartesian coordinate system to verify the result for P(-5,3), P(3,1), P(-1,2) Screen output example: A : +1.142857142857 +0.571428571428 -0.285714285714 -0.142857142857 p: A point of the plan -5.0 +3.0 Pp: The projection of p on the line -4.0 +1.0 Press return to continue.