" i have 2 classes "
prec1, prec5 = accuracy(output.data, target, topk=(1,5))
def accuracy(output, target, topk=(1,)):
maxk = max(topk)

batch_size = target.size(0)

print(maxk)

_, 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)

    res.append(correct_k.mul_(100.0 / batch_size))

return res