Our FREE site is mostly funded by the Amazon ads ⇓below⇓.

Support us by clicking ⇑above⇑ next time you plan to buy a product on Amazon.

"""Lower-Upper (LU) Decomposition."""
# lowerâ€“upper (LU) decomposition - https://en.wikipedia.org/wiki/LU_decomposition
import numpy
def LUDecompose(table):
# Table that contains our data
# Table has to be a square array so we need to check first
rows, columns = numpy.shape(table)
L = numpy.zeros((rows, columns))
U = numpy.zeros((rows, columns))
if rows != columns:
return []
for i in range(columns):
for j in range(i - 1):
sum = 0
for k in range(j - 1):
sum += L[i][k] * U[k][j]
L[i][j] = (table[i][j] - sum) / U[j][j]
L[i][i] = 1
for j in range(i - 1, columns):
sum1 = 0
for k in range(i - 1):
sum1 += L[i][k] * U[k][j]
U[i][j] = table[i][j] - sum1
return L, U
if __name__ == "__main__":
matrix = numpy.array([[2, -2, 1], [0, 1, 2], [5, 3, 1]])
L, U = LUDecompose(matrix)
print(L)
print(U)