from __future__ import absolute_import
from __future__ import print_function
from __future__ import division


def accuracy(output, target, topk=(1,)):
    """Computes the accuracy over the k top predictions for
    the specified values of k
    """
    maxk = max(topk)
    batch_size = target.size(0)

    if isinstance(output, (tuple, list)):
        output = output[0]

    _, pred = output.topk(maxk, 1, True, True)
    pred = pred.t()
    correct = pred.eq(target.view(1, -1).expand_as(pred))

    res = []
    for k in topk:
        correct_k = correct[:k].view(-1).float().sum(0, keepdim=True)
        acc = correct_k.mul_(100.0 / batch_size)
        res.append(acc)
    
    return res