pop list

nifty6/operators/einsum.py

@@ -46,7 +46,7 @@ class MultiLinearEinsum(Operator):
         `key_order` is not part of the `domain`. Fields in this object are
         supposed to be static as they will not appear as FieldAdapter in the
         Linearization.
-    optimize: bool, String or List optional
+    optimize: bool, String or List, optional
         Parameter passed on to einsum_path.
     """
     def __init__(self, domain, subscripts,
@@ -68,7 +68,7 @@ class MultiLinearEinsum(Operator):
             raise ValueError(f"invalid subscripts specified; got {subscripts}")
         ve = f"invalid order of keys {self._key_order} for subscripts {subscripts}"
         shapes, numpy_subscripts,  subscriptmap = {},'',{}
-        alphabet = list(string.ascii_lowercase)
+        alphabet = list(string.ascii_lowercase)[::-1]
         for k, ss in zip(self._key_order, iss_spl):
             dom = self._domain[k] if k in self._domain.keys(
             ) else self._stat_mf[k].domain
@@ -76,8 +76,8 @@ class MultiLinearEinsum(Operator):
                 raise ValueError(ve)
             for i, a in enumerate(list(ss)):
                 if a not in subscriptmap.keys():
-                    subscriptmap[a] = alphabet[:len(dom[i].shape)].copy()
-                    del alphabet[:len(dom[i].shape)]
+                    subscriptmap[a] = [alphabet.pop() for _ in
+                                       range(len(dom[i].shape))]
                 numpy_subscripts += ''.join(subscriptmap[a])
             numpy_subscripts += ','
             shapes[k] = dom.shape
@@ -177,7 +177,7 @@ class LinearEinsum(LinearOperator):
     key_order: tuple of str, optional
         The order of the keys in the multi-field. If not specified, defaults to
         the order of the keys in the multi-field.
-    optimize: bool, String or List optional
+    optimize: bool, String or List, optional
         Parameter passed on to einsum_path.
     """
     def __init__(self, domain, mf, subscripts, key_order=None, optimize='optimal'):
@@ -203,8 +203,8 @@ class LinearEinsum(LinearOperator):
                 raise ValueError(ve)
             for i, a in enumerate(list(ss)):
                 if a not in subscriptmap.keys():
-                    subscriptmap[a] = alphabet[:len(dom[i].shape)].copy()
-                    del alphabet[:len(dom[i].shape)]
+                    subscriptmap[a] = [alphabet.pop() for _ in
+                                       range(len(dom[i].shape))]
                 numpy_subscripts += ''.join(subscriptmap[a])
             numpy_subscripts += ','
             shapes +=(dom.shape,)
@@ -212,8 +212,8 @@ class LinearEinsum(LinearOperator):
             raise ValueError(ve)
         for i, a in enumerate(list(iss_spl[-1])):
             if a not in subscriptmap.keys():
-                subscriptmap[a] = alphabet[:len(self._domain[i].shape)].copy()
-                del alphabet[:len(self._domain[i].shape)]
+                subscriptmap[a] = [alphabet.pop() for _ in
+                                   range(len(self._domain[i].shape))]
             numpy_subscripts += ''.join(subscriptmap[a])
         shapes += (self._domain.shape,)
         numpy_subscripts += '->'