Merge pull request sympy#19229 from sylee957/fix_ndarray_matrix

oscarbenjamin · web-flow · commit 0b42f52d9128 · 2020-04-30T10:02:10.000+01:00
Fix creation of matrix with list of ndarray
diff --git a/sympy/matrices/matrices.py b/sympy/matrices/matrices.py
@@ -900,6 +900,23 @@ def irregular(cls, ntop, *matrices, **kwargs):
           rows.append(r)
       return cls._new(rows)
 
+    @classmethod
+    def _handle_ndarray(cls, arg):
+        # NumPy array or matrix or some other object that implements
+        # __array__. So let's first use this method to get a
+        # numpy.array() and then make a python list out of it.
+        arr = arg.__array__()
+        if len(arr.shape) == 2:
+            rows, cols = arr.shape[0], arr.shape[1]
+            flat_list = [cls._sympify(i) for i in arr.ravel()]
+            return rows, cols, flat_list
+        elif len(arr.shape) == 1:
+            flat_list = [cls._sympify(i) for i in arr]
+            return arr.shape[0], 1, flat_list
+        else:
+            raise NotImplementedError(
+                "SymPy supports just 1D and 2D matrices")
+
     @classmethod
     def _handle_creation_inputs(cls, *args, **kwargs):
         """Return the number of rows, cols and flat matrix elements.
@@ -973,23 +990,7 @@ def _handle_creation_inputs(cls, *args, **kwargs):
 
             # Matrix(numpy.ones((2, 2)))
             elif hasattr(args[0], "__array__"):
-                # NumPy array or matrix or some other object that implements
-                # __array__. So let's first use this method to get a
-                # numpy.array() and then make a python list out of it.
-                arr = args[0].__array__()
-                if len(arr.shape) == 2:
-                    rows, cols = arr.shape[0], arr.shape[1]
-                    flat_list = [cls._sympify(i) for i in arr.ravel()]
-                    return rows, cols, flat_list
-                elif len(arr.shape) == 1:
-                    rows, cols = arr.shape[0], 1
-                    flat_list = [cls.zero] * rows
-                    for i in range(len(arr)):
-                        flat_list[i] = cls._sympify(arr[i])
-                    return rows, cols, flat_list
-                else:
-                    raise NotImplementedError(
-                        "SymPy supports just 1D and 2D matrices")
+                return cls._handle_ndarray(args[0])
 
             # Matrix([1, 2, 3]) or Matrix([[1, 2], [3, 4]])
             elif is_sequence(args[0]) \
@@ -1064,13 +1065,19 @@ def do(x):
                         if not is_sequence(row) and \
                                 not getattr(row, 'is_Matrix', False):
                             raise ValueError('expecting list of lists')
-                        if not row:
+
+                        if hasattr(row, '__array__'):
+                            if 0 in row.shape:
+                                continue
+                        elif not row:
                             continue
+
                         if evaluate and all(ismat(i) for i in row):
                             r, c, flatT = cls._handle_creation_inputs(
                                 [i.T for i in row])
                             T = reshape(flatT, [c])
-                            flat = [T[i][j] for j in range(c) for i in range(r)]
+                            flat = \
+                                [T[i][j] for j in range(c) for i in range(r)]
                             r, c = c, r
                         else:
                             r = 1
diff --git a/sympy/matrices/tests/test_matrices.py b/sympy/matrices/tests/test_matrices.py
@@ -2601,8 +2601,11 @@ def test_from_ndarray():
     assert Matrix(array([[1, 2, 3], [4, 5, 6]])) == \
         Matrix([[1, 2, 3], [4, 5, 6]])
     assert Matrix(array([x, y, z])) == Matrix([x, y, z])
-    raises(NotImplementedError, lambda: Matrix(array([[
-        [1, 2], [3, 4]], [[5, 6], [7, 8]]])))
+    raises(NotImplementedError,
+        lambda: Matrix(array([[[1, 2], [3, 4]], [[5, 6], [7, 8]]])))
+    assert Matrix([array([1, 2]), array([3, 4])]) == Matrix([[1, 2], [3, 4]])
+    assert Matrix([array([1, 2]), [3, 4]]) == Matrix([[1, 2], [3, 4]])
+    assert Matrix([array([]), array([])]) == Matrix([])
 
 def test_17522_numpy():
     from sympy.matrices.common import _matrixify
