Fix spurious cholesky_det test failures

Before, the `cholesky_det` test would (infrequently) fail randomly due
to small numerical errors. This commit adjusts the precision of the
test and changes to an absolute (instead of relative) comparison to
prevent those spurious failures.

Author: jturner314

tests/cholesky.rs

@@ -101,19 +101,19 @@ fn cholesky_inverse() {
 #[test]
 fn cholesky_det() {
     macro_rules! cholesky_det {
-        ($elem:ty, $rtol:expr) => {
+        ($elem:ty, $atol:expr) => {
             let a: Array2<$elem> = random_hpd(3);
             println!("a = \n{:?}", a);
             let det = a.eigvalsh(UPLO::Upper).unwrap().mapv(|elem| elem.ln()).scalar_sum().exp();
-            assert_rclose!(a.detc().unwrap(), det, $rtol);
-            assert_rclose!(a.factorizec(UPLO::Upper).unwrap().detc(), det, $rtol);
-            assert_rclose!(a.factorizec(UPLO::Lower).unwrap().detc(), det, $rtol);
+            assert_aclose!(a.detc().unwrap(), det, $atol);
+            assert_aclose!(a.factorizec(UPLO::Upper).unwrap().detc(), det, $atol);
+            assert_aclose!(a.factorizec(UPLO::Lower).unwrap().detc(), det, $atol);
         }
     }
     cholesky_det!(f64, 1e-9);
-    cholesky_det!(f32, 1e-4);
+    cholesky_det!(f32, 1e-3);
     cholesky_det!(c64, 1e-9);
-    cholesky_det!(c32, 1e-4);
+    cholesky_det!(c32, 1e-3);
 }
 
 #[test]