在 15*8-2**x=x 中求解 x 的公式求解器未完成计算

如何解决在 15*8-2**x=x 中求解 x 的公式求解器未完成计算

所以我不知道根本问题是什么（我不知道它是否发生在任何其他公式中），但是每当我输入 15*8-2^x=x 并用我的公式求解 x求解器使用 r = solve(leftside - rightside,user_choice) 程序永远不会完成运行。我在函数中有 pprint(r) 行，但程序永远不会到达那个点。 （-2**x=x 求解 x 效果很好）

在我终止程序后，我收到二十条错误消息，例如：

File "/Users/myusername/.conda/envs/formula calculator/lib/python3.8/site-packages/sympy/solvers/solvers.py",line 1095,in solve
    solution = _solve(f[0],*symbols,**flags)

我在 Symbolab 中尝试了 15*8-2**x=x 并且它解决得很好： https://www.symbolab.com/solver/step-by-step/solve%20for%20x%2C%2015%5Ccdot8-2%5E%7Bx%7D%3Dx

*我不是数学家，这些计算超出了我的理解，我只是觉得很奇怪，当 Symbolab 设法解决它时，它从未完成或显示错误。那么是什么导致了这种行为？

编辑：堆栈跟踪：

Traceback (most recent call last):
  File "/Users/torrinleonard/PycharmProjects/formula calculator/Complete_solver.py",line 38,in <module>
    Rearrange_input()
  File "/Users/torrinleonard/PycharmProjects/formula calculator/Complete_solver.py",line 29,in Rearrange_input
    r = solve(l - r,user_choice)
  File "/Users/torrinleonard/.conda/envs/formula calculator/lib/python3.8/site-packages/sympy/solvers/solvers.py",**flags)
  File "/Users/torrinleonard/.conda/envs/formula calculator/lib/python3.8/site-packages/sympy/solvers/solvers.py",line 1717,in _solve
    result = list(map(simplify,result))
  File "/Users/torrinleonard/.conda/envs/formula calculator/lib/python3.8/site-packages/sympy/simplify/simplify.py",line 606,in simplify
    expr = expr.replace(
  File "/Users/torrinleonard/.conda/envs/formula calculator/lib/python3.8/site-packages/sympy/core/basic.py",line 1497,in replace
    rv = walk(self,rec_replace)
  File "/Users/torrinleonard/.conda/envs/formula calculator/lib/python3.8/site-packages/sympy/core/basic.py",line 1471,in walk
    newargs = tuple([walk(a,F) for a in args])
  File "/Users/torrinleonard/.conda/envs/formula calculator/lib/python3.8/site-packages/sympy/core/basic.py",in <listcomp>
    newargs = tuple([walk(a,line 1481,in walk
    rv = F(rv)
  File "/Users/torrinleonard/.conda/envs/formula calculator/lib/python3.8/site-packages/sympy/core/basic.py",line 1490,in rec_replace
    v = _value(expr,result)
  File "/Users/torrinleonard/.conda/envs/formula calculator/lib/python3.8/site-packages/sympy/core/basic.py",line 1455,in <lambda>
    _value = lambda expr,result: value(expr)
  File "/Users/torrinleonard/.conda/envs/formula calculator/lib/python3.8/site-packages/sympy/simplify/simplify.py",line 614,in <lambda>
    lambda x: x.func(*[simplify(i,**kwargs) for i in x.args]),File "/Users/torrinleonard/.conda/envs/formula calculator/lib/python3.8/site-packages/sympy/simplify/simplify.py",in <listcomp>
    lambda x: x.func(*[simplify(i,line 699,in simplify
    expr = shorter(expand_log(expr,deep=True),logcombine(expr))
  File "/Users/torrinleonard/.conda/envs/formula calculator/lib/python3.8/site-packages/sympy/simplify/simplify.py",line 1119,in logcombine
    return bottom_up(expr,f)
  File "/Users/torrinleonard/.conda/envs/formula calculator/lib/python3.8/site-packages/sympy/simplify/simplify.py",line 1198,in bottom_up
    rv = F(rv)
  File "/Users/torrinleonard/.conda/envs/formula calculator/lib/python3.8/site-packages/sympy/simplify/simplify.py",line 1097,in f
    log1[Mul(*k)] = log(logcombine(Mul(*[
  File "/Users/torrinleonard/.conda/envs/formula calculator/lib/python3.8/site-packages/sympy/simplify/simplify.py",line 1098,in <listcomp>
    l.args[0]**Mul(*c) for c,l in log1.pop(k)]),File "/Users/torrinleonard/.conda/envs/formula calculator/lib/python3.8/site-packages/sympy/core/expr.py",line 239,in __pow__
    return self._pow(other)
  File "/Users/torrinleonard/.conda/envs/formula calculator/lib/python3.8/site-packages/sympy/core/decorators.py",line 266,in _func
    return func(self,other)
  File "/Users/torrinleonard/.conda/envs/formula calculator/lib/python3.8/site-packages/sympy/core/decorators.py",line 136,in binary_op_wrapper
    return func(self,other)
  File "/Users/torrinleonard/.conda/envs/formula calculator/lib/python3.8/site-packages/sympy/core/expr.py",line 235,in _pow
    return Pow(self,other)
  File "/Users/torrinleonard/.conda/envs/formula calculator/lib/python3.8/site-packages/sympy/core/cache.py",line 72,in wrapper
    retval = cfunc(*args,**kwargs)
  File "/Users/torrinleonard/.conda/envs/formula calculator/lib/python3.8/site-packages/sympy/core/power.py",line 336,in __new__
    obj = b._eval_power(e)
  File "/Users/torrinleonard/.conda/envs/formula calculator/lib/python3.8/site-packages/sympy/core/numbers.py",line 2347,in _eval_power
    result = Integer(x**abs(expt.p))
KeyboardInterrupt

解决方法

看起来常数的大小引起了麻烦，因为较小的值很容易解决：

>>> from sympy.abc import x
>>> from sympy import *
>>> solve(1-2**x-x)
[0]
>>> solve(2-2**x-x)
[(-LambertW(log(16)) + log(4))/log(2)]
>>> solve(5-2**x-x)
[(-LambertW(log(4294967296)) + log(32))/log(2)]

但是，在这种情况下，确切的值无助于找到解决方案，因此我们可以将 120 替换为 Symbol('120')：

>>> solve(Symbol('120')-2**x-x,x)
120 - LambertW(exp(120*log(2))*log(2))/log(2)

正如@oscar-benjamin 指出的那样，设置 simpliy=False 将在相同的时间内给出答案，但您也会在结果中得到一个大整数：

[-LambertW(1329227995784915872903807060280344576*log(2))/log(2) + 120]

如果您只想要一个数值，您可以直接使用 nsolve 和对解决方案的合理猜测：

>>> nsolve(120-2**x-x,7)
6.82244407754025