Merge pull request mpmath#1005 from baranwalayush/fix/matrix_ValueError

Fix mpmath#1004: Matrix should raise ValueError in case of negative dimensions

Author: skirpichev

mpmath/matrices/matrices.py

@@ -320,10 +320,14 @@ def __init__(self, *args, **kwargs):
         elif isinstance(args[0], int):
             # create empty matrix of given dimensions
             if len(args) == 1:
+                if args[0] < 0:
+                    raise ValueError("expected non-negative int")
                 self._rows = self._cols = args[0]
             else:
                 if not isinstance(args[1], int):
                     raise TypeError("expected int")
+                if args[0] < 0 or args[1] < 0:
+                    raise ValueError("expected non-negative int")
                 self._rows = args[0]
                 self._cols = args[1]
         elif isinstance(args[0], _matrix):

mpmath/tests/test_matrices.py

@@ -75,6 +75,9 @@ def test_matrix_basic():
     A10[-3, -2] = 1
     assert A10[-3, -2] == 1
 
+    pytest.raises(ValueError, lambda: matrix(-2))
+    pytest.raises(ValueError, lambda: matrix(2, -3))
+
 def test_matmul():
     """
     Test the PEP465 "@" matrix multiplication syntax.