""" Common Helpers

Hacked together by Ross Wightman
"""
from itertools import repeat
from torch._six import container_abcs


# From PyTorch internals
def _ntuple(n):
    def parse(x):
        if isinstance(x, container_abcs.Iterable):
            return x
        return tuple(repeat(x, n))
    return parse


tup_single = _ntuple(1)
tup_pair = _ntuple(2)
tup_triple = _ntuple(3)
tup_quadruple = _ntuple(4)


# Calculate symmetric padding for a convolution
def get_padding(kernel_size: int, stride: int = 1, dilation: int = 1, **_) -> int:
    padding = ((stride - 1) + dilation * (kernel_size - 1)) // 2
    return padding