https://lists.gnu.org/archive/html/help-gsl/2017-02/msg00002.html

--- gsl-2.4/linalg/test_cholesky.c.old	2017-06-19 10:00:43.000000000 +0000
+++ gsl-2.4/linalg/test_cholesky.c	2018-05-30 07:37:04.835628069 +0000
@@ -551,7 +551,7 @@
       if (N <= 4)
         {
           create_hilbert_matrix2(m);
-          test_mcholesky_invert_eps(m, 256.0 * N * GSL_DBL_EPSILON, "mcholesky_invert unscaled hilbert");
+          test_mcholesky_invert_eps(m, 512.0 * N * GSL_DBL_EPSILON, "mcholesky_invert unscaled hilbert");
         }
 
       gsl_matrix_free(m);