[Python] Python numpy how to split a matrix into 4 not equal matrixes?

from sympy import *
import numpy as np

# Python 3.13.2
u1 = Symbol("u1")
u2 = Symbol("u2")
q3 = Symbol("q3")
u4 = Symbol("u4")
q5 = Symbol("q5")

disp_vector = np.array([u1, u2, q3, u4, q5])

stiffness_matrix = np.array([[1, 0, 0, -1, 0],
[0, 0.12, 0.6, 0, 0.6],
[0, 0.6, 4, 0, 2],
[-1, 0, 0, 1, 0],
[0, 0.6, 2, 0, 4]])

force_vector = np.array([0, 40, -26.7, 0, 0])


I am trying to code static condensation. This allows me to reduce the size of the stiffness matrix above but for that I need to be able to divide the stiffness matrix into following matrices.

krr = np.array([[1, 0, 0],
[0, 0.12, 0.6],
[0, 0.6, 4]])

krc = np.array([[-1, 0],
[0, 0.6],
[0, 2]])

kcr = np.array([[-1, 0, 0],
[0, 0.6, 2]])

kcc = np.array([[1, 0],
[0, 4]])


How would I do this ?

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