fixed coprime error when encountering NaN

python/damask/util.py

@@ -173,7 +173,7 @@ def scale_to_coprime(v):
     m = m//reduce(np.gcd,m)
 
     with np.errstate(divide='ignore'):
-        if not np.allclose(v/m,v[0]/m[0]):
+        if not np.allclose(np.ma.masked_invalid(v/m),v[np.argmax(abs(v))]/m[np.argmax(abs(v))]):
             raise ValueError(f'Invalid result {m} for input {v}. Insufficient precision?')
 
     return m

python/tests/test_util.py

@@ -18,16 +18,17 @@ class TestUtil:
 
     @pytest.mark.parametrize('input,output',
                             [
-                            ([2,0],[1,0]),
-                            ([0.5,0.5],[1,1]),
+                            ([0,-2],[0,-1]),
+                            ([-0.5,0.5],[-1,1]),
                             ([1./2.,1./3.],[3,2]),
                             ([2./3.,1./2.,1./3.],[4,3,2]),
                             ])
 
     def test_scale2coprime(self,input,output):
+        print(util.scale_to_coprime(np.array(input)))
         assert np.allclose(util.scale_to_coprime(np.array(input)),
                                                  np.array(output).astype(int))
 
     def test_lackofprecision(self):
         with pytest.raises(ValueError):
-            util.scale_to_coprime(np.array([1/3333,1,1]))
+            util.scale_to_coprime(np.array([1/333.333,1,1]))