'Compute the derivative of the cost function
Arguments:
inputs (Tensor): Tensor containing input values to be compared to
targets
targets (Tensor): Tensor containing target values.
Returns:
Tensor of same shape as the inputs containing their respective
deltas.'

def get_errors(self, inputs, targets):

    self.deltas[:] = self.costfunc.bprop(inputs, targets)
    return self.deltas
