How to calculate RMSE using IPython/NumPy?
Question: I'm having issues trying to calculate root mean squared error in IPython using
NumPy. I'm pretty sure the function is right, but when I try and input values,
it gives me the following TypeError message:

    
    
    TypeError: unsupported operand type(s) for -: 'tuple' and 'tuple'
    

Here's my code:

    
    
    import numpy as np
    
    def rmse(predictions, targets):
        return np.sqrt(((predictions - targets) ** 2).mean())
    
    print rmse((2,2,3),(0,2,6))
    

Obviously something is wrong with my inputs. Do I need to establish the array
before I put it in the `rmse():` line?


Answer: It says that subtraction is not defined for tuples.

Try

    
    
    print rmse(np.array([2,2,3]), np.array([0,2,6]))
    

instead.

