-(IBAction) balancer: (id) sender{ double M[4][4]; M[0][0] = 6.0; M[0][1] = 0.0; M[0][2] = -1.0; M[0][3] = 0.0; M[1][0] = 12.0; M[1][1] = 0.0; M[1][2] = 0.0; M[1][3] = 2.0; M[2][0] = 6.0; M[2][1] = 2.0; M[2][2] = -2.0; M[2][3] = 1.0; M[3][0] = 0.0; M[3][1] = 0.0; M[3][2] = 0.0; M[3][3] = 0.0; int rowCount = 4;

int columnCount = 4;

int lead = 0; for (int r = 0; r < rowCount; r++) { if (lead >= columnCount) break;

int i = r; while (M[i][lead] == 0) { i++; if (i == rowCount) { i = r; lead++; if (lead == columnCount){

 break;
}

} } double temp[4] ; temp[0] = M[r][0]; temp[1] = M[r][1]; temp[2] = M[r][2]; temp[3] = M[r][3]; M[r][0] = M[i][0]; M[r][1] = M[i][1]; M[r][2] = M[i][2]; M[r][3] = M[i][3]; M[i][0] = temp[0]; M[i][1] = temp[1]; M[i][2] = temp[2]; M[i][3] = temp[3];

double lv = M[r][lead]; for (int j = 0; j < columnCount; j++) M[r][j] = M[r][j] / lv;

for (int f = 0; f < rowCount; f++) { if (f != r) { double l = M[f][lead]; for (int j = 0; j < columnCount; j++) M[f][j] = M[f][j] - l * M[r][j]; } } lead++;

}

NSString* myNewString = [NSString stringWithFormat:@"%g",M[0][3]];

label1.text = myNewString;

}

This is returning NaN, while it should be returning .16666667 for M[0][3]. Any suggestions on how to fix this?