I do not know solve well but I suspect that it cannot handle vector
equations. There should probably be separate equations for the components.
Kalevi Suominen
On Saturday, October 30, 2021 at 9:28:06 AM UTC+3 Andreas Schuldei wrote:
> I have a system of longish equations and when calling .solve() on it, I
> get this traceback:
>
> Traceback (most recent call last):
> File "C:/Users/Andreas
> Schuldei/PycharmProjects/lissajous-achse/hgü-kabel-detektion-symbolic.py",
> line 109, in <module>
> result = solve(equations, (CM0, theta_i, theta_j, theta_k, i, a,
> B_earth))
> File "C:\Users\Andreas
> Schuldei\PycharmProjects\lissajous-achse\venv\lib\site-packages\sympy\solvers\solvers.py",
>
> line 1096, in solve
> solution = _solve_system(f, symbols, **flags)
> File "C:\Users\Andreas
> Schuldei\PycharmProjects\lissajous-achse\venv\lib\site-packages\sympy\solvers\solvers.py",
>
> line 1730, in _solve_system
> i, d = _invert(g, *symbols)
> File "C:\Users\Andreas
> Schuldei\PycharmProjects\lissajous-achse\venv\lib\site-packages\sympy\solvers\solvers.py",
>
> line 3118, in _invert
> rhs -= indep
> File "C:\Users\Andreas
> Schuldei\PycharmProjects\lissajous-achse\venv\lib\site-packages\sympy\core\numbers.py",
>
> line 2194, in __sub__
> return Rational.__sub__(self, other)
> File "C:\Users\Andreas
> Schuldei\PycharmProjects\lissajous-achse\venv\lib\site-packages\sympy\core\decorators.py",
>
> line 89, in __sympifyit_wrapper
> return func(a, b)
> File "C:\Users\Andreas
> Schuldei\PycharmProjects\lissajous-achse\venv\lib\site-packages\sympy\core\numbers.py",
>
> line 1725, in __sub__
> return Number.__sub__(self, other)
> File "C:\Users\Andreas
> Schuldei\PycharmProjects\lissajous-achse\venv\lib\site-packages\sympy\core\decorators.py",
>
> line 89, in __sympifyit_wrapper
> return func(a, b)
> File "C:\Users\Andreas
> Schuldei\PycharmProjects\lissajous-achse\venv\lib\site-packages\sympy\core\numbers.py",
>
> line 733, in __sub__
> return AtomicExpr.__sub__(self, other)
> File "C:\Users\Andreas
> Schuldei\PycharmProjects\lissajous-achse\venv\lib\site-packages\sympy\core\decorators.py",
>
> line 251, in _func
> return func(self, other)
> File "C:\Users\Andreas
> Schuldei\PycharmProjects\lissajous-achse\venv\lib\site-packages\sympy\core\decorators.py",
>
> line 126, in binary_op_wrapper
> return f(self)
> File "C:\Users\Andreas
> Schuldei\PycharmProjects\lissajous-achse\venv\lib\site-packages\sympy\core\decorators.py",
>
> line 127, in binary_op_wrapper
> return func(self, other)
> File "C:\Users\Andreas
> Schuldei\PycharmProjects\lissajous-achse\venv\lib\site-packages\sympy\vector\basisdependent.py",
>
> line 352, in __rsub__
> raise TypeError("Invalid argument types for subtraction")
> TypeError: Invalid argument types for subtraction
>
> Process finished with exit code 1
>
> I stared at my code long and hard, and fixed all instances of wrong types
> that i could think of. Also, in order to catch the error earlier, I tried
> insterting .simplify() calls in places that might benefit from them - but
> the process ran for hours, doing the simplyfy() without even reaching the
> solve() call.
>
> So I am asking for tricks to investigate the types and them fitting
> together, earlier. You can find my code attached. (please critique it, I
> want to learn!).
>
>
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