def __new__(cls, *args, **kwargs):
if not args:
return GenericZeroMatrix()
# This must be removed aggressively in the constructor to avoid
# TypeErrors from GenericZeroMatrix().shape
args = filter(lambda i: GenericZeroMatrix() != i, args)
args = list(map(sympify, args))
check = kwargs.get('check', False)
obj = Basic.__new__(cls, *args)
if check:
if all(not isinstance(i, MatrixExpr) for i in args):
return Add.fromiter(args)
validate(*args)
return obj
def test_generic_zero_matrix():
z = GenericZeroMatrix()
A = MatrixSymbol("A", n, n)
assert z == z
assert z != A
assert A != z
assert z.is_ZeroMatrix
raises(TypeError, lambda: z.shape)
raises(TypeError, lambda: z.rows)
raises(TypeError, lambda: z.cols)
assert MatAdd() == z
assert MatAdd(z, A) == MatAdd(A)
# Make sure it is hashable
hash(z)
class MatAdd(MatrixExpr, Add):
"""A Sum of Matrix Expressions
MatAdd inherits from and operates like SymPy Add
Examples
========
>>> from sympy import MatAdd, MatrixSymbol
>>> A = MatrixSymbol('A', 5, 5)
>>> B = MatrixSymbol('B', 5, 5)
>>> C = MatrixSymbol('C', 5, 5)
>>> MatAdd(A, B, C)
A + B + C
"""
is_MatAdd = True
identity = GenericZeroMatrix()
def __new__(cls, *args, **kwargs):
if not args:
return cls.identity
# This must be removed aggressively in the constructor to avoid
# TypeErrors from GenericZeroMatrix().shape
args = filter(lambda i: cls.identity != i, args)
args = list(map(sympify, args))
check = kwargs.get("check", False)
obj = Basic.__new__(cls, *args)
if check:
if all(not isinstance(i, MatrixExpr) for i in args):
return Add.fromiter(args)
validate(*args)
return obj
@property
def shape(self):
return self.args[0].shape
def _entry(self, i, j, **kwargs):
return Add(*[arg._entry(i, j, **kwargs) for arg in self.args])
def _eval_transpose(self):
return MatAdd(*[transpose(arg) for arg in self.args]).doit()
def _eval_adjoint(self):
return MatAdd(*[adjoint(arg) for arg in self.args]).doit()
def _eval_trace(self):
from .trace import trace
return Add(*[trace(arg) for arg in self.args]).doit()
def doit(self, **kwargs):
deep = kwargs.get("deep", True)
if deep:
args = [arg.doit(**kwargs) for arg in self.args]
else:
args = self.args
return canonicalize(MatAdd(*args))
def _eval_derivative_matrix_lines(self, x):
add_lines = [arg._eval_derivative_matrix_lines(x) for arg in self.args]
return [j for i in add_lines for j in i]
def test_generic_identity():
assert MatAdd.identity == GenericZeroMatrix()
assert MatAdd.identity != S.Zero
