code improvement exercise: solver.py

solver.py

from numpy.random import random
from numpy import array, isclose, zeros_like, sign
from numpy.linalg import lstsq

def solve(func, values, atol=0.1):
    while True:
        result = func(values)
        if isclose(result, 0, atol=atol):
            break
        values -= sign(result) * random(values.size)
    return values

def linear(coeffs, constant):
    return lambda values: (coeffs * values).sum() + constant

if __name__ == '__main__':
    coeffs = array([1., 2., 3., 4., 5.])
    constant = 7
    eq = linear(coeffs, constant)

    print('With `solve`:')
    vs = solve(eq, zeros_like(coeffs), atol=1e-4)
    print(f'vs = {", ".join(f"{v:.4f}" for v in vs)}')
    print(f'eq(vs) = {eq(vs):.4f}')

    print()

    vs, _, _, _ = lstsq([coeffs], [-constant], rcond=None)
    print('With `numpy.linalg.lstsq`:')
    print(f'vs = {", ".join(f"{v:.4f}" for v in vs)}')
    print(f'eq(vs) = {eq(vs):.4f}')