condensed scale_to_coprime; added test of scale_to_coprime

python/damask/util.py

@@ -166,10 +166,13 @@ def scale_to_coprime(v):
         """Least common multiple."""
         return a * b // np.gcd(a, b)
 
-    denominators = [int(get_square_denominator(i)) for i in v]
-    s = reduce(lcm, denominators) ** 0.5
-    m = (np.array(v)*s).astype(np.int)
-    return m//reduce(np.gcd,m)
+    m = (np.array(v) * reduce(lcm, map(lambda x: int(get_square_denominator(x)),v)) ** 0.5).astype(np.int)
+    m = m//reduce(np.gcd,m)
+
+    if not np.allclose(v/m,v[0]/m[0]):
+        raise ValueError(f'Invalid result {m} for input {v}. Insufficient precision?')
+
+    return m
 
 
 ####################################################################################################

python/tests/test_util.py

@@ -1,11 +1,32 @@
+import pytest
+import numpy as np
 from damask import util
 
+
 class TestUtil:
 
     def test_execute_direct(self):
         out,err = util.execute('echo test')
         assert out=='test\n' and err==''
-    
+
     def test_execute_env(self):
         out,err = util.execute('sh -c "echo $test_for_execute"',env={'test_for_execute':'test'})
         assert out=='test\n' and err==''
+
+    def test_croak(self):
+        util.croak('Burp!')
+
+    @pytest.mark.parametrize('input,output',
+                            [
+                            ([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):
+        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([0.66,0.5,0.33]))