test_problem.py 文件源码

def test_expand():
    """ Ensure that an equation is expanded correctly. """

    equations = ["Eq(Der(rho,t), -c*Conservative(rhou_j,x_j))"]
    substitutions = []
    ndim = 1
    constants = ["c"]
    coordinate_symbol = "x"
    metrics = [False, False]
    formulas = ["Eq(u_i, rhou_i/rho)"]

    problem = Problem(equations, substitutions, ndim, constants, coordinate_symbol, metrics, formulas)

    expanded_equations = flatten(problem.get_expanded(problem.equations))
    expanded_formulas = flatten(problem.get_expanded(problem.formulas))

    assert len(expanded_equations) == 1
    assert str(expanded_equations[0].lhs) == "Derivative(rho[x0, t], t)"
    assert str(expanded_equations[0].rhs) == "-c*Derivative(rhou0[x0, t], x0)"

    assert len(expanded_formulas) == 1
    assert str(expanded_formulas[0].lhs) == "u0[x0, t]"
    assert str(expanded_formulas[0].rhs) == "rhou0[x0, t]/rho[x0, t]"

    # Test the other way of expanding equations
    assert expanded_equations == flatten(problem.get_expanded(problem.expand(equations)))

    return