I am new to sympy, and trying to utilize solve to solve systems of
linear equations. However there a couple things I have been unable to
figure out.
The most important is how get diagnostic information about why the
solve call failed (returned None). The system of equations I am
solving for are pretty simple, I am problem just miss using the
interface. However with the only output of the system being returning
None, I have no way to figure out my mistake.
So here is an example I am trying:
from sympy import Symbol, solve
C = Symbol('C', constant=True, real=True)
R = Symbol('R', constant=True, real=True)
Rf = Symbol('Rf', constant=True, real=True)
Ri = Symbol('Ri', constant=True, real=True)
s = Symbol('s')
V1 = Symbol('V1')
Vminus = Symbol('Vminus')
Vplus = Symbol('Vplus')
Vout = Symbol('Vout')
eqs = [C*V1*s + Vplus*(-2*C*s - 1/R), Vminus*(-1/Ri - 1/Rf) + Vout/Rf,
C*Vplus*s + V1*(-C*s - 1/R) + Vout/R, -Vminus + Vplus]
print solve(eqs, Vout)
What I want to see is:
Vout = Vplus*(s**2*C**2 + 3*s*C/R + 1/R^2)/(s*C/R)
When I worked it by hand there was another solution
Vout = Vminus*(1/Ri + 1/Rf)*Rf
so that is likely the problem. However is there any way for sympy to
give me both solutions? Or at least indicate that was the problem?
Thanks.
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