Linear Algebra and the C Language/a0gi


Install and compile this file in your working directory.

/* ------------------------------------ */
/*  Save as :  c00b.c                   */
/* ------------------------------------ */
#include "v_a.h"
/* ------------------------------------ */
#define  ARRAY  A3 
#define    RCA  R3  
/* ------------------------------------ */
void fun(void)
{
double **A[ARRAY];
double **P[ARRAY];
double **InvP[ARRAY];

double **T = i_mR(RCA,RCA);
int i;

  for(i=A0; i<ARRAY; i++)
     {   
         A[i] =              i_mR(RCA,RCA); 
         P[i] =   r_mR(      i_mR(RCA,RCA),99); 
      InvP[i] = inv_mR(P[i], i_mR(RCA,RCA));       
	   } 

  rsymmetric_mR(A[0],99);
  
    for(i=A0; i<(ARRAY-C1); i++)
     {   
        mul_mR(InvP[i],A[i],T); 
        mul_mR(T,P[i],A[i+C1]);
	   } 
	   
  clrscrn();
  printf(" Similar matrices have the same trace.\n\n");
  
  for(i=A0; i<ARRAY; i++)
     {
      printf(" A[%d] : \t\t\t trace = %+.4f ",i,trace_R(A[i]));      
      p_mR(A[i], S9,P2,C6); 
     } 

  for(i=A0; i<ARRAY; i++)
     { 
	   f_mR(A[i]);
	   f_mR(P[i]);		 
	   f_mR(InvP[i]); 
	   }
	   
  f_mR(T);       
}
/* ------------------------------------ */
int main(void)
{
time_t t;

  srand(time(&t));
  
  do{
        fun();
        
  }while(stop_w());

  return 0;
}
/* ------------------------------------ */
/* ------------------------------------ */


Screen output example:

                                                                                       
 Similar matrices have the same trace.

 A[0] : 			 trace = -165.0000 
    +7.00     -7.00    +60.00 
    -7.00    -80.00    -56.00 
   +60.00    -56.00    -92.00 

 A[1] : 			 trace = -165.0000 
  +103.09   -139.06   +162.85 
  -261.21   +186.50   -284.36 
  -322.58   +336.14   -454.59 

 A[2] : 			 trace = -165.0000 
    -0.47    +62.65    -43.33 
  -275.89   -307.30   +126.09 
  -269.54   -297.92   +142.77 


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