sympy怎么看运行过程

如果你想在运行 sympy 时查看其运行过程，可以通过以下两种方法之一来实现：

1. 使用 Python 的 `logging` 模块

你可以使用 Python 自带的 `logging` 模块来记录 sympy 的运行过程。首先，你需要在代码中导入 `logging` 模块：

import logging

然后，你需要配置 `logging` 模块的输出级别，设置为 `DEBUG` 级别，以便记录所有详细信息：

logging.basicConfig(level=logging.DEBUG)

最后，你可以在代码中使用 `logging.debug()` 函数来记录 sympy 的运行过程：

from sympy import *
import logging

logging.basicConfig(level=logging.DEBUG)

x = symbols('x')
expr = x**2 + 2*x + 1
logging.debug(f"expr = {expr}")

在运行以上代码时，你会看到类似下面的输出：

DEBUG:root:expr = x**2 + 2*x + 1

这就是 `logging` 模块记录的 sympy 运行过程。

2. 使用 IPython 的 `%debug` 魔法命令

如果你在 IPython 中运行 sympy，你可以使用 `%debug` 魔法命令来查看 sympy 的运行过程。当代码发生错误时，你可以在错误信息中输入 `%debug` 命令，进入调试模式，查看代码的运行过程。

例如，假设你有以下代码：

from sympy import *

x = symbols('x')
expr = x**2 + 2*x + 1
result = solve(expr, x)

如果在运行 `solve()` 函数时发生错误，你会看到类似下面的错误信息：

Traceback (most recent call last):
  File "<ipython-input-1-5aef1d3e8baf>", line 4, in <module>
    result = solve(expr, x)
  File "/usr/local/lib/python3.7/site-packages/sympy/solvers/solvers.py", line 1046, in solve
    solution = _solve(f[0], *symbols, **flags)
  File "/usr/local/lib/python3.7/site-packages/sympy/solvers/solvers.py", line 1595, in _solve
    soln = checksol(f_num, symbol, soln, solve_for_symbol)
  File "/usr/local/lib/python3.7/site-packages/sympy/solvers/solvers.py", line 1948, in checksol
    if not checksol_all(sol, f_num):
  File "/usr/local/lib/python3.7/site-packages/sympy/solvers/solvers.py", line 1931, in checksol_all
    return all(checksol(sol, eq) for eq in f)
  File "/usr/local/lib/python3.7/site-packages/sympy/solvers/solvers.py", line 1931, in <genexpr>
    return all(checksol(sol, eq) for eq in f)
  File "/usr/local/lib/python3.7/site-packages/sympy/solvers/solvers.py", line 1953, in checksol
    if not checksol_any(sol, eq):
  File "/usr/local/lib/python3.7/site-packages/sympy/solvers/solvers.py", line 1912, in checksol_any
    return any(checksol(sol, eq) for eq in eqs)
  File "/usr/local/lib/python3.7/site-packages/sympy/solvers/solvers.py", line 1912, in <genexpr>
    return any(checksol(sol, eq) for eq in eqs)
  File "/usr/local/lib/python3.7/site-packages/sympy/solvers/solvers.py", line 1972, in checksol
    return eq.subs(sol) == S.Zero
  File "/usr/local/lib/python3.7/site-packages/sympy/core/basic.py", line 1091, in subs
    rv = self._subs(old, new, **hints)
  File "/usr/local/lib/python3.7/site-packages/sympy/core/basic.py", line 1245, in _subs
    return self.func(*args)
  File "/usr/local/lib/python3.7/site-packages/sympy/core/expr.py", line 291, in __new__
    return cls._from_args(cls, args)
  File "/usr/local/lib/python3.7/site-packages/sympy/core/expr.py", line 194, in _from_args
    return cls._from_args_join(args)
  File "/usr/local/lib/python3.7/site-packages/sympy/core/mul.py", line 595, in _from_args_join
    con, short = split_mul(args)
  File "/usr/local/lib/python3.7/site-packages/sympy/core/mul.py", line 188, in split_mul
    for a in args:
TypeError: 'Symbol' object is not iterable

在错误信息中输入 `%debug` 命令，你会进入调试模式，可以查看代码的运行过程：

> /usr/local/lib/python3.7/site-packages/sympy/core/mul.py(188)split_mul()
    186             con, short = con, []
    187         else:
--> 188             for a in args:
    189                 if a.is_commutative:
    190                     con.append(a)

ipdb> args
(Symbol('x'),)

ipdb> p type(args[0])
<class 'sympy.core.symbol.Symbol'>

ipdb> c

在调试模式中，你可以使用 `args` 命令来查看当前函数的参数，使用 `p` 命令来打印变量的值，使用 `c` 命令来继续执行代码。