test_immutable.py 文件源码

def test_function_return_types():
    # Lets ensure that decompositions of immutable matrices remain immutable
    # I.e. do MatrixBase methods return the correct class?
    X = ImmutableMatrix([[1, 2], [3, 4]])
    Y = ImmutableMatrix([[1], [0]])
    q, r = X.QRdecomposition()
    assert (type(q), type(r)) == (ImmutableMatrix, ImmutableMatrix)

    assert type(X.LUsolve(Y)) == ImmutableMatrix
    assert type(X.QRsolve(Y)) == ImmutableMatrix

    X = ImmutableMatrix([[1, 2], [2, 1]])
    assert X.T == X
    assert X.is_symmetric
    assert type(X.cholesky()) == ImmutableMatrix
    L, D = X.LDLdecomposition()
    assert (type(L), type(D)) == (ImmutableMatrix, ImmutableMatrix)

    assert X.is_diagonalizable()
    assert X.berkowitz_det() == -3
    assert X.norm(2) == 3

    assert type(X.eigenvects()[0][2][0]) == ImmutableMatrix

    assert type(zeros(3, 3).as_immutable().nullspace()[0]) == ImmutableMatrix

    X = ImmutableMatrix([[1, 0], [2, 1]])
    assert type(X.lower_triangular_solve(Y)) == ImmutableMatrix
    assert type(X.T.upper_triangular_solve(Y)) == ImmutableMatrix

    assert type(X.minorMatrix(0, 0)) == ImmutableMatrix

# issue 6279
# https://github.com/sympy/sympy/issues/6279
# Test that Immutable _op_ Immutable => Immutable and not MatExpr