# Author: Alex Gezerlis

# Numerical Methods in Physics with Python (CUP, 2020)

from triang import backsub, testcreate, testsolve

import numpy as np

def gauelim_pivot(inA,inbs):

A = np.copy(inA)

bs = np.copy(inbs)

n = bs.size

for j in range(n-1):

k = np.argmax(np.abs(A[j:,j])) + j

if k != j:

A[j,:], A[k,:] = A[k,:], A[j,:].copy()

bs[j], bs[k] = bs[k], bs[j]

for i in range(j+1,n):

coeff = A[i,j]/A[j,j]

A[i,j:] -= coeff*A[j,j:]

bs[i] -= coeff*bs[j]

xs = backsub(A,bs)

return xs

if __name__ == '__main__':

A, bs = testcreate(4,21)

testsolve(gauelim_pivot,A,bs)