Added an option for the threshold level of the 0/0 generalized eigenvalue test.

The option is passed in the fourth input argument of mjdgges. If the
mex is called with less than four arguments, then the threshold level
takes its previous (hardcoded) default value: 1e-6.

mex/sources/mjdgges/mjdgges.c

@@ -32,7 +32,7 @@ my_criteria(const double *alphar, const double *alphai, const double *beta)
 }
 
 void
-mjdgges(double *a, double *b, double *z, double *n, double *sdim, double *eval_r, double *eval_i, double *info)
+mjdgges(double *a, double *b, double *z, double *n, double *sdim, double *eval_r, double *eval_i, double zhreshold, double *info)
 {
   lapack_int i_n, i_info, i_sdim, lwork;
   double *alphar, *alphai, *beta, *work, *par, *pai, *pb, *per, *pei;
@@ -60,7 +60,7 @@ mjdgges(double *a, double *b, double *z, double *n, double *sdim, double *eval_r
   pei = eval_i;
   for (per = eval_r; per <= &eval_r[i_n-1]; ++per)
     {
-      if ((fabs(*par) > 1e-6) || (fabs(*pb) > 1e-6)) 
+      if ((fabs(*par) > zhreshold) || (fabs(*pb) > zhreshold)) 
 	*per = *par / *pb;
       else
 	{
@@ -136,6 +136,18 @@ mexFunction(int nlhs, mxArray *plhs[],
       criterium = 1+1e-6;
     }
 
+  /* set criterium for 0/0 generalized eigenvalues */
+  double zhreshold;
+  if (nrhs == 4 && mxGetM(prhs[3]) > 0)
+    {
+      zhreshold = *mxGetPr(prhs[3]);
+    }
+  else
+    {
+      zhreshold = 1e-6;
+    }
+
+
   /* keep a and b intact */
   memcpy(s, a, sizeof(double)*n1*n1);
   memcpy(t, b, sizeof(double)*n1*n1);
@@ -143,7 +155,7 @@ mexFunction(int nlhs, mxArray *plhs[],
   n = n1;
 
   /* Do the actual computations in a subroutine */
-  mjdgges(s, t, z, &n, sdim, eval_r, eval_i, info);
+  mjdgges(s, t, z, &n, sdim, eval_r, eval_i, zhreshold, info);
 
   plhs[0] = mxCreateDoubleScalar(0);
 }