#include "ABACUS.h"
using namespace std;

void ABACUS::balanc(SQMat_DP& a)
{
  // Balancing of nonsymmetric matrix.  See NR p.489.

  const DP RADIX = numeric_limits<DP>::radix;

  int i, j, last = 0;
  DP s, r, g, f, c, sqrdx;

  int n = a.size();
  sqrdx = RADIX * RADIX;

  while (last == 0) {
    last = 1;
    for (i = 0; i < n; i++) {
      r = c = 0.0;
      for (j = 0; j < n; j++)
	if (j != i) {
	  c += fabs(a[j][i]);
	  r += fabs(a[i][j]);
	}
      if (c != 0.0 && r != 0.0) {
	g = r/RADIX;
	f = 1.0;
	s = c + r;
	while (c < g) {
	  f *= RADIX;
	  c *= sqrdx;
	}
	g = r * RADIX;
	while (c > g) {
	  f /= RADIX;
	  c /= sqrdx;
	}
	if ((c + r)/f < 0.95 * s) {
	  last = 0;
	  g = 1.0/f;
	  for (j = 0; j < n; j++) a[i][j] *= g;
	  for (j = 0; j < n; j++) a[j][i] *= f;
	}
      }
    }
  }
}