fix: small divide by zero errors

Author: CPrescher

glassure/transform.py

@@ -214,5 +214,6 @@ def calculate_gr(fr_pattern: Pattern, atomic_density: float) -> Pattern:
     :return: g(r) pattern
     """
     r, f_r = fr_pattern.data
-    g_r = 1 + f_r / (4.0 * np.pi * r * atomic_density)
+    r_safe = np.where(r == 0, 1e-10, r)
+    g_r = 1 + f_r / (4.0 * np.pi * r_safe * atomic_density)
     return Pattern(r, g_r)

tests/test_fitting.py

@@ -14,6 +14,7 @@ def setUp(self):
 
     def test_i_q_peak(self):
         q = np.linspace(0, 10, 1001)
+        q[0] = 1e-10
         peak = i_q_peak(q, 4, 1.6, 0.1, self.composition, 'Si', 'O')
         self.assertEqual(len(peak), len(q))