def sum_of_sq()

in lattices/Zn_lattice.py [0:0]

• 18 lines of code
• 8 McCabe index (conditional complexity)

def sum_of_sq(total, v, n):
    """find all positive integer vectors of size n:
    - whose squared elements sum to total
    - maximium value is v
    """

    if total < 0:
        return []
    elif total == 0:
        return [[0] * n]
    elif n == 1:
        while v * v > total:
            v -= 1
        if v * v == total:
            return [[v]]
        else:
            return []
    else:
        res = []
        for vi in range(v, -1, -1):
            res += [[vi] + vv for vv in
                    sum_of_sq(total - vi * vi, vi, n - 1)]
        return res