另一种方法使用sympy,Python的符号数学包:
from sympy import Eq, solve
from sympy.abc import w, x, y, z
sol = solve([ Eq(2*w + x + 4*y + 3*z, 5),
Eq(w - 2*x + 3*z, 3),
Eq(3*w + 2*x - y + z, -1),
Eq(4*x - 5*z, -3) ])
print(sol)
print({ s:sol[s].evalf() for s in sol })
这将打印:
{w: 94/45, x: -20/9, y: 74/45, z: -53/45}
{w: 2.08888888888889, x: -2.22222222222222, y: 1.64444444444444, z: -1.17777777777778}
直接使用字符串输入并找到解决方案也是可能的:
from sympy import Eq, solve
from sympy.parsing.sympy_parser import parse_expr, standard_transformations, implicit_multiplication_application
eqs = ['2w + x + 4y + 3z = 5',
'w - 2x + 3z = 3',
'3w + 2x - y + z = -1',
'4x - 5z = -3']
transformations=(standard_transformations + (implicit_multiplication_application,))
eqs_sympy = [Eq(parse_expr(e.split('=')[0], transformations=transformations),
parse_expr(e.split('=')[1], transformations=transformations))
for e in eqs]
sol = solve(eqs_sympy)
print(sol)