def log_loss(y, t, eps=1e-15):
    y = T.clip(y, eps, 1 - eps)
    loss = -T.sum(t * T.log(y)) / y.shape[0].astype(theano.config.floatX)
    return loss
cross entropy loss, summed over classes, mean over batches
dataset/ETHPy150Open benanne/kaggle-ndsb/nn_plankton.py/log_loss