pde.py 文件源码

def pde_separate_mul(eq, fun, sep):
    """
    Helper function for searching multiplicative separable solutions.

    Consider an equation of two independent variables x, y and a dependent
    variable w, we look for the product of two functions depending on different
    arguments:

    `w(x, y, z) = X(x)*u(y, z)`

    Examples
    ========

    >>> from sympy import Function, Eq, pde_separate_mul, Derivative as D
    >>> from sympy.abc import x, y
    >>> u, X, Y = map(Function, 'uXY')

    >>> eq = Eq(D(u(x, y), x, 2), D(u(x, y), y, 2))
    >>> pde_separate_mul(eq, u(x, y), [X(x), Y(y)])
    [Derivative(X(x), x, x)/X(x), Derivative(Y(y), y, y)/Y(y)]

    """
    return pde_separate(eq, fun, sep, strategy='mul')