[Bug-gsl] bug in gsl_root_test_delta()

[Dave Spiegel]

Dear bug-gsl,

I think that I have found a bug in the function gsl_root_test_delta.

When x1 and x0 are both 0.0, gsl_root_test_delta returns -2, indicating 
failure to converge.

For instance, the following line of code:

  printf("Testing gsl_root_test_delta: %d\n", gsl_root_test_delta(0., 
0., 0., 1e-3));

results in the following output:

  Testing gsl_root_test_delta: -2


Best,
Dave Spiegel