/* ------------------------------------ */
/*  Save as :   wepivot.h               */
/* ------------------------------------ */
/* ------------------------------------
   pivotbest = |a+bI|^2 =  = a^2+b^2
   ------------------------------------ */
double pivotbest_mZ(
double **A,
int pivot_r,
int pivot_c
)
{
double pivotbest = A[pivot_r][pivot_c]   *A[pivot_r][pivot_c]
                                     +
                   A[pivot_r][pivot_c+C1]*A[pivot_r][pivot_c+C1];
double sign = 1.;
int best_r = pivot_r;
int best_c = pivot_c;

double value;
int r;
int c;

  for( r=pivot_r; r<A[R_SIZE][C0]; r++)

    for( c=pivot_c; c<A[C_SIZE][C0]; c+=C2)
         {
          value = A[r][c]*A[r][c] + A[r][c+C1]*A[r][c+C1]; 

          if(value>pivotbest)
             {
               pivotbest=value;  
               best_r = r;
               best_c = c;
             }
         }

 if(best_r!=pivot_r){ sign*=-1; swapR_mZ(A,pivot_r,best_r); }
 if(best_c!=pivot_c){ sign*=-1; swapC_mZ(A,pivot_c,best_c); }

 return(sign);
}
/* ------------------------------------ */
nb_Z zero_under_pivot_mZ(
double **A,
int pivot_r,
int pivot_c
)
{
double abspivot = A[pivot_r][pivot_c]   *A[pivot_r][pivot_c]
                                     +
                  A[pivot_r][pivot_c+C1]*A[pivot_r][pivot_c+C1];
nb_Z pivot;
int r;

    
  if(abspivot>ERROR_E)
    {
      pivot = c_coef_Z(A,pivot_r,pivot_c);

      mulR_mZ( A,
               inv_Z(pivot),
               pivot_r);

     for( r=(pivot_r+C1); r<A[R_SIZE][C0]; r++)

         addR_mZ( A,
                  sym_Z(c_coef_Z(A,r,pivot_c)),
                  pivot_r,
                  r);
    }
    else pivot = i_Z(0,0);

 return(pivot);
}
/* ------------------------------------ */
/* ------------------------------------ */