Correctness Test of det_by

correct_det_by_minor_c

@(@\newcommand{\W}[1]{ \; #1 \; } \newcommand{\R}[1]{ {\rm #1} } \newcommand{\B}[1]{ {\bf #1} } \newcommand{\D}[2]{ \frac{\partial #1}{\partial #2} } \newcommand{\DD}[3]{ \frac{\partial^2 #1}{\partial #2 \partial #3} } \newcommand{\Dpow}[2]{ \frac{\partial^{#1}}{\partial {#2}^{#1}} } \newcommand{\dpow}[2]{ \frac{ {\rm d}^{#1}}{{\rm d}\, {#2}^{#1}} }@)@Correctness Test of det_by_minor Routine
Syntax
flag = correct_det_by_minor()

flag
The return value has prototype



     bool flag

It value is 1 if the test passes and 0 otherwise.

Source Code

bool correct_det_by_minor(void)
{     double a[9], det, check;

     random_seed(123);
     uniform_01(9, a);

     /* compute determinant using expansion by minors */
     det = det_by_minor(a, 3);

     /* use expansion by minors to hand code the determinant  */
     check = 0.;
     check += a[0] * ( a[4] * a[8] - a[5] * a[7] );
     check -= a[1] * ( a[3] * a[8] - a[5] * a[6] );
     check += a[2] * ( a[3] * a[7] - a[4] * a[6] );

     double eps99 = 99.0 * DBL_EPSILON;
     if( fabs(det / check - 1.0) < eps99 )
          return true;
     return false;
}

Input File: test_more/compare_c/det_by_minor.c