Linear Algebra and the C Language/a0el

/* ------------------------------------ */
/*  Save as :    c00a.c                 */
/* ------------------------------------ */
#include "v_a.h"
/*

 The zero row and the zero column are not used!!!
 
 In the row zero  you have an index  for the columns.
 In the columns zero you have the size of the matrix.
 
 see the pall_mR(); function.

                      *********************

 The size of the rows    is into  A[R_SIZE][C0] = A[R0][C0]
 The size of the columns is into  A[C_SIZE][C0] = A[R1][C0]

                      *********************

 The first  element  of the  matrix  is: A[R1 ][ C1]
 For a 10x10 matrix the last element is: A[R10][C10]

                      *********************
*/

/* ------------------------------------ */
/* ------------------------------------ */ 
double **x_i_mR(
int      r,
int      c
)
{
double **A;
int     ar;
int     ac;
int      i;

    if(r<R1||c<C1)
      {
       printf(" The size of the matrix must be positive integers.\n\n");
       printf(" double **i_mR(); \n\n");
       fflush(stdout);
       getchar();
       exit(EXIT_FAILURE);
      }

         ar = r + R1;              /* I add a row.    The row    zero */
         ac = c + C1;              /* I add a column. The column zero */


                 /* *************** */
                 
    A = malloc(ar * sizeof(*A));
    if(!A)
      {
       printf(" I was unable to allocate the memory you requested.\n\n");
       printf(" double **i_mR(); \n\n");
       printf(" **A = malloc(ar * sizeof(*A));\n\n");
       fflush(stdout);
       getchar();
       exit(EXIT_FAILURE);
       }

    A[0] = malloc(ar * ac * sizeof(**A) );
    if(!A[0])
      {
       printf(" I was unable to allocate the memory you requested.\n\n");
       printf(" double **i_mR();\n\n");
       printf(" A[0] = malloc(ar * ac * sizeof(**A) );\n\n");
       fflush(stdout);
       getchar();
       exit(EXIT_FAILURE);
      }

	for(i=R1; i<ar; i++) A[i] = A[0]+i*ac;

                 /* *************** */
                 
                 
    A[R_SIZE][C0] = ar;             /* I copy the number of lines     */
    A[C_SIZE][C0] = ac;             /* I copy the number of columns   */


    for(r=R2; r<A[R_SIZE][C0]; r++) /* I set the zero column to zero  */ 
                                    /* without touching the size of   */
        A[r][C0] = 0.;              /* the matrix.                    */ 


    for(c=C1; c<A[C_SIZE][C0]; c++) /* I put the index in the row zero*/

        A[R0][c] = c;              

    m0_mR(A);                        /* Set all coefficients to zero  */

return(A);
}
/* ------------------------------------ */ 
/* ------------------------------------ */
void fun(int r,int c)
{
double **A     = r_mR(x_i_mR(r,c),9);

  clrscrn();

  printf(" A[R%d,C%d]:          (p_mR();)\n",rsize_R(A),csize_R(A));
  p_mR(A, S4,P0,C8);

  printf("\n\n\n");
  printf(" A[R%d,C%d]:          (pall_mR();)\n",rsize_R(A),csize_R(A));
  pall_mR(A, S4,P0,C9);
 
  f_mR(A);
}
/* ------------------------------------ */
int main(void)
{
time_t t;

  srand(time(&t));
  
   do 
        fun(rp_I(R4),rp_I(C8));
        
    while(stop_w());
        
  return 0;
}
/* ------------------------------------ */
/* ------------------------------------ */

                                                                                       
 A[R3,C6]:          (p_mR();)

  +4   -7   -5   -4   +2   +1 
  +3   -5   -2   -3   +8   +6 
  +7   +7   -7   -7   +9   +4 




 A[R3,C6]:          (pall_mR();)
+4        +1   +2   +3   +4   +5   +6 

+7        +4   -7   -5   -4   +2   +1 
+0        +3   -5   -2   -3   +8   +6 
+0        +7   +7   -7   -7   +9   +4 


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