Capacitance equation solver with Sympy example

capsolver.py

from sympy.parsing.sympy_parser import parse_expr
from sympy.solvers import solve
from itertools import zip_longest

def display_results(inputs, solutions):
    columns = '{:25} {:25}'.format
    print(columns('Input', 'Solutions'),
          columns('-' * 25, '-' * 25),
        *[columns(i, o) for i, o in zip_longest(
            ('{} = {}'.format(var, value) for var, value in sorted(inputs.items())),
            ('{} = {}'.format(var, value) for sol in solutions for var, value in sorted(sol.items())),
            fillvalue='')],
          sep='\n', end='\n\n')

def parallel_plate(**kwargs):
    eqn = parse_expr('e_0*e_r*A/D - C')
    vals = dict(e_0=8.85e-12, **kwargs)
    solution = solve(eqn.subs(vals), dict=True)
    display_results(vals, solution)

parallel_plate(A=0.01*0.01, e_r=1, D=0.001)

parallel_plate(C=1e-12, e_r=1, D=0.001)

parallel_plate(C=1e-12, D=0.001, A=0.01*0.1)

parallel_plate(C=1e-12, e_r=1)

output.txt

Input                     Solutions
------------------------- -------------------------
A = 0.0001                C = 8.85000000000000e-13
D = 0.001
e_0 = 8.85e-12
e_r = 1

Input                     Solutions
------------------------- -------------------------
C = 1e-12                 A = 0.000112994350282486
D = 0.001
e_0 = 8.85e-12
e_r = 1

Input                     Solutions
------------------------- -------------------------
A = 0.001                 e_r = 0.112994350282486
C = 1e-12
D = 0.001
e_0 = 8.85e-12

Input                     Solutions
------------------------- -------------------------
C = 1e-12                 A = 0.112994350282486*D
e_0 = 8.85e-12
e_r = 1