我正在使用 SymPy 來(lái)求解方程，代碼如下。我做了一個(gè)更簡(jiǎn)單的例子，但這個(gè)問(wèn)題可能與原始方程有關(guān)，所以我會(huì)選擇在這里發(fā)布原始代碼而不是簡(jiǎn)化的代碼。from sympy import *dP, rho, nu, D, miu, L, Q, Re, eps, f = symbols('dP, rho, nu, D, miu, L, Q, Re, eps, f')solve([Eq(Re, rho * nu * D / mu),       Eq(L / D, 0.05 * Re),       Eq(L / D, 1.359 * Re ** (1/4)),       Eq(dP, 32 * miu * L * nu / D ** 2),       Eq(dP, 128 * miu * L * Q / pi / D ** 2),       Eq(dP, f * (L/D) * (rho * nu ** 2 / 2)),       Eq(f, 64 / Re),       Eq(1 / sqrt(f), -1.8 * log ((eps / D / 3.7) ** 1.11 + 6.9 / Re))],      [Re, D, f])帶有錯(cuò)誤消息：UnboundLocalError                         Traceback (most recent call last)<ipython-input-13-884b0835e135> in <module>      7        Eq(f, 64 / Re),      8        Eq(1 / sqrt(f), -1.8 * log ((eps / D / 3.7) ** 1.11 + 6.9 / Re))],----> 9       [Re, D, f])G:\Program-Files\anaconda3\lib\site-packages\sympy\solvers\solvers.py in solve(f, *symbols, **flags)   1094         solution = _solve(f[0], *symbols, **flags)   1095     else:-> 1096         solution = _solve_system(f, symbols, **flags)   1097    1098     #G:\Program-Files\anaconda3\lib\site-packages\sympy\solvers\solvers.py in _solve_system(exprs, symbols, **flags)   1834             return rv   1835 -> 1836         solved_syms = set(solved_syms)  # set of symbols we have solved for   1837         legal = set(symbols)  # what we are interested in   1838         # sort so equation with the fewest potential symbols is firstUnboundLocalError: local variable 'solved_syms' referenced before assignment