ufunc 'add' did not contain a loop with signature matching types (dtype('<U4'), dtype('float64')) -> None

This error message suggests that there is an issue with the input data types being used with the 'add' ufunc. Specifically, it seems that the 'add' ufunc is expecting inputs of type float64, but one of the inputs is of type '<U4' (which likely represents a Unicode string with a length of 4 characters).

To resolve this issue, you may need to convert the input data to the correct type before passing it to the 'add' ufunc. For example, if you have a numpy array with mixed data types, you could use the astype() method to convert all elements to a specific data type:

import numpy as np

# create a mixed-type numpy array
arr = np.array(['1', 2, 3.0, '4.0'])

# convert all elements to float64
arr = arr.astype('float64')

# use the 'add' ufunc to add two arrays
result = np.add(arr, [5.0, 6.0, 7.0, 8.0])

In this example, the astype() method is used to convert all elements in the 'arr' array to float64. The 'add' ufunc can then be used to add the 'arr' array to another array of float64 values.