feat: added alloy perturbation

metallurgy/generate.py

@@ -535,3 +535,63 @@ def quaternary(
         alloys.append(ternary_alloys)
 
     return alloys
+
+
+def perturb(alloy, size=0.05):
+    if isinstance(alloy, list):
+        return [perturb(a) for a in alloy]
+
+    composition = dict(alloy.composition)
+    structure = alloy.structure
+    constraints = alloy.constraints
+    if "local_percentages" in constraints:
+        del constraints["local_percentages"]
+    if "digits" in constraints:
+        del constraints["digits"]
+
+    for element in composition:
+        composition[element] += round(
+            float(np.random.random(1) * 2 - 1) * size, 2
+        )
+        composition[element] = max(composition[element], 0)
+
+    elements = list(composition.keys())
+    if len(composition) > 1:
+        for element in elements:
+            if composition[element] < 0.0001:
+                if (
+                    constraints is not None
+                    and element in constraints["percentages"]
+                    and constraints["percentages"][element]["precedence"] > 0
+                ):
+                    continue
+                del composition[element]
+
+    if np.random.random(1) > 0.1:
+        allowed_elements = list(mg.periodic_table.elements.keys())
+        if constraints is not None and "allowed_elements" in constraints:
+            allowed_elements = constraints["allowed_elements"][:]
+        for element in composition:
+            if element in allowed_elements:
+                allowed_elements.remove(element)
+        if len(allowed_elements) > 0:
+            composition[np.random.choice(allowed_elements)] = round(
+                float(np.random.random(1)) * size, 2
+            )
+
+    elif len(composition) > 1 and np.random.random(1) > 0.1:
+        to_delete = np.random.choice(list(composition.keys()))
+        if not (
+            constraints is not None
+            and to_delete in constraints["percentages"]
+            and constraints["percentages"][to_delete]["precedence"] > 0
+        ):
+            del composition[to_delete]
+
+    if structure is not None and np.random.random(1) > 0.1:
+        structure = get_random_prototype()
+
+    new_alloy = mg.Alloy(
+        composition, constraints=constraints, structure=structure
+    )
+    return new_alloy