def sum_to(x, shape): if x.shape == shape: return as_variable(x) return SumTo(shape)(x)
def broadcast_to(x, shape): if x.shape == shape: return as_variable(x) return BroadcastTo(shape)(x)
def cos(x): x = as_variable(x) return Cos()(x)
def tanh(x): x = as_variable(x) return Tanh()(x)
def sin(x): x = as_variable(x) return Sin()(x)