python – 由于Theano和NumPy变量类型而出错

import theano.tensor as T
from theano import function
import numpy as np
import pprint
def test_theano_matrix():
   pp = pprint.PrettyPrinter(indent=3)
   W= T.fmatrix()
   x=T.fvector()
   b= T.fvector()
   y = T.dot(W,x) + b
   lin_func = function([W,x,b],y)
   dt = np.dtype(np.float)
   w_inp = np.matrix('1 0;0 1',dtype=dt)
   x_inp = np.matrix('2;1',dtype=dt)
   b_inp = np.matrix('0;0',dtype=dt)
   lin_func(w_inp,x_inp,b_inp)

 if __name__ == '__main__':
   test_theano_matrix()

我收到以下错误：

raise TypeError(err_msg,data)
TypeError: ('Bad input argument to theano function at index 0(0-based)','TensorType(float32,matrix) cannot store a value of dtype float64 without risking loss of precision. If you do not mind this loss,you can: 1) explicitly cast your data to float32,or 2) set "allow_input_downcast=True" when calling "function".',matrix([[ 1.,0.],[ 0.,1.]]))

谢谢你的时间！