Recently I had to work with Theano, numpy, scipy libraries in python. had to pass hour with this this piece of error which says TypeError: (‘Bad input argument to theano function at index 1(0-based)’, ‘Wrong number of dimensions: expected 2, got 1 with shape (2,).’) So here it goes, how I fixed it.

For the sake helping other fellow programmers, I am posting the whole error log, which will help them via google:

/usr/lib/python2.7/dist-packages/scipy/lib/_util.py:35: DeprecationWarning: Module scipy.linalg.blas.fblas is deprecated, use scipy.linalg.blas instead DeprecationWarning) /usr/lib/python2.7/dist-packages/scipy/lib/_util.py:35: DeprecationWarning: Module scipy.linalg.blas.fblas is deprecated, use scipy.linalg.blas instead DeprecationWarning) /usr/lib/python2.7/dist-packages/scipy/lib/_util.py:35: DeprecationWarning: Module scipy.linalg.blas.fblas is deprecated, use scipy.linalg.blas instead DeprecationWarning) /usr/lib/python2.7/dist-packages/scipy/lib/_util.py:35: DeprecationWarning: Module scipy.linalg.blas.fblas is deprecated, use scipy.linalg.blas instead DeprecationWarning) /usr/lib/python2.7/dist-packages/scipy/lib/_util.py:35: DeprecationWarning: Module scipy.linalg.blas.fblas is deprecated, use scipy.linalg.blas instead DeprecationWarning) /usr/lib/python2.7/dist-packages/scipy/lib/_util.py:35: DeprecationWarning: Module scipy.linalg.blas.fblas is deprecated, use scipy.linalg.blas instead DeprecationWarning) /usr/lib/python2.7/dist-packages/scipy/lib/_util.py:35: DeprecationWarning: Module scipy.linalg.blas.fblas is deprecated, use scipy.linalg.blas instead DeprecationWarning) /usr/lib/python2.7/dist-packages/scipy/lib/_util.py:35: DeprecationWarning: Module scipy.linalg.blas.fblas is deprecated, use scipy.linalg.blas instead DeprecationWarning) False Traceback (most recent call last): File "bgd.py", line 44, intheta = gradient_descent_2(alpha, x, y, 2000) File "bgd.py", line 24, in gradient_descent_2 hypothesis =find_hypothesis(x, theta).T File "/usr/local/lib/python2.7/dist-packages/Theano-0.6.0-py2.7.egg/theano/compile/function_module.py", line 497, in __call__ allow_downcast=s.allow_downcast) File "/usr/local/lib/python2.7/dist-packages/Theano-0.6.0-py2.7.egg/theano/tensor/type.py", line 157, in filter data.shape)) TypeError: ('Bad input argument to theano function at index 1(0-based)', 'Wrong number of dimensions: expected 2, got 1 with shape (2,).')

So basically it is saying that in my code there is a shape mismatch, apparently there should not be any mismatch, because I coded everything, I KNOW what I did! But apparently there is something in numpy that makes a matrix without height, which means with blank height. So it has a shape of (2, ).

Example could be:

import numpy as np theta = np.array([1,1]) print theta.shape #(2,)

It works pretty fine when you are working with nupy alone, but it causes tremendous problems when you are using other library like THENO.

Now let me share another snippet, from where I got this error:

from theano import tensor as T, function T_x,T_y, T_z, T_theta, T_loss = T.dmatrices('x','y','z','theta','loss') find_hypothesis=function([T_x,T_theta],T.dot(T_x,T_theta)) hypothesis =find_hypothesis(x, theta).T

From code like this you will get the error I previously mentioned.

Now lets talk about how did I fix it, actually it was simple, I passed hours without any reason. You can solve it just by reshapiing your numpy like this:

theta=theta.reshape(theta.shape[0],1) #had tough time without this,