Fixed test for complex eigenvectors

wangfeng012316 · Jul 25, 2019 · 99342df · 99342df
1 parent c030e0b
commit 99342df
Showing 1 changed file with 3 additions and 1 deletion.
diff --git a/tests/test_linalg.py b/tests/test_linalg.py
@@ -210,7 +210,9 @@ def fun(x):
     hmat = broadcast_dot_transpose(mat, mat)
     check_grads(fun)(hmat)
 
-# For complex-valued matrices, the gradient only works for the eigenvalues, but not for the eigenvectors
+# For complex-valued matrices, the eigenvectors could have arbitrary phases (gauge)
+# which makes it impossible to compare to numerical derivatives. So we take the 
+# absolute value to get rid of that phase. 
 def test_eigvalh_lower_complex():
     def fun(x):
         w, v = np.linalg.eigh(x)