CODEWITHSUNDEEP
pythonsympy
Johannes
Johannes

Reputation: 111

How to calculate the product of the diagonal in Sympy?

I have given a sympy matrix, so a matrix consisting of real values and symbolic values and I want to calculate the product of diagonal entries of the matrix; An example:

import numpy as np
import sympy as sp
from sympy import *
from sympy.matrices import Matrix

A=sp.Matrix([[1,0,1],[2,3,1],[y,5,x]])

Now the desired result would be 3x; Of course I could do that with a for loop but is there some other, cleaner solution?

Upvotes: 0

Views: 240

Answers (2)

kakkeuno
kakkeuno

Reputation: 140

Oscar Benjamin provided a slick solution. This will work as well:

np.product(np.diag(A))

Upvotes: 0

Oscar Benjamin
Oscar Benjamin

Reputation: 14470

You can use diagonal to get the diagonal elements and prod to multiply them:


In [46]: A.diagonal()
Out[46]: [1  3  x]

In [47]: prod(_)
Out[47]: 3⋅x

Upvotes: 1

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