Not Implemented Error when solving a equation system

[rgbarriada]

Hi all,

I am trying to solve a very simple equation system. Here is the code:

import sympy as sp
a, b, c, d = sp.S('a b c d'.split())
equations = [
     sp.Eq(a, b+c/d),
     sp.Eq(c, 60.),
     sp.Eq(d, 5.)]

print sp.solve(equations)

So I can have an expression for 'a' as a function of 'b'.

I am getting this error instead:

...
  File "/usr/lib/python2.7/dist-packages/sympy/solvers/solvers.py", line 484, in solve
    solution = _solve(f, *symbols, **flags)
  File "/usr/lib/python2.7/dist-packages/sympy/solvers/solvers.py", line 730, in _solve
    raise NotImplementedError()
NotImplementedError


I am using sympy 0.7.1.

Any hint of what I am doing wrong?

Thanks in advance

[Mateusz Paprocki]

Hi,

Nothing, besides using an older version of SymPy. If you try 0.7.5 (or
0.7.4), your example works perfectly there. Note that you can still
encounter NotImplementedError in case of equations/systems that SymPy
doesn't support. Also, may I suggest using exact numbers, i.e. 60
instead of 60., unless you really want to use a numerical solver (if
this is how SymPy works in this particular case).

> Thanks in advance
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Mateusz