I would like to use a matrix with complex entries to construct a new matrix, but it gives me the warning
"ComplexWarning: Casting complex values to real discards the imaginary part".
As a result, the new matrix's entries are all real numbers. How to make all the entries keep their imaginary part?
This is the image containing my original code
2 Answers
I know where I make this warning happen.
I need to add dtype = "complex_", when I construct a new empty matrix.
For example,
mat__ = np.zeros((k*nboxes,k*nboxes),dtype = 'complex_') If we just write
mat__ = np.zeros((k*nboxes,k*nboxes)) and do some manipulations on that like using a complex matrix to forming a new matrix, then the new matrix will discard the imaginary part.
You could try using numpy to create a new matrix from your Matrix_1 with the array constructor. That way you can specify that you are using Complex numbers with the dtype. Something like this should do the trick:
mat_ = np.array(matrix_1[:,ll,ll,:],dtype = "complex_")
Some testing that I used to make sure:
import numpy as np abc = np.array([[1+1j,2+2j,3+3j],[4+4j,5+5j,6+6j],[7+7j,8+8j,9+9j]],dtype = "complex_") # initial print(abc) abc2 = np.array(abc[1:,:1],dtype = "complex_") # post transformation print(abc2) 
