Construct symmetric block matrix in Python

Asked Jul 09 '20 at 00:20

Active Jul 09 '20 at 00:36

Viewed 81 times

For example, I got the following 2D array

a= np.array([[1,2,3],
[2,5,6],
[3,6,9]])

If I know the dimension of each block square matrix of diagonal, i.e

2,3,2

How can I generate the following 2D block array

[[1,1,2,2,2,3,3],
[1,1,2,2,2,3,3],
[2,2,5,5,5,6,6],
[2,2,5,5,5,6,6],
[2,2,5,5,5,6,6],
[3,3,6,6,6,9,9],
[3,3,6,6,6,9,9]]

edited Jul 09 '20 at 00:36

asked Jul 09 '20 at 00:20

Nicolas H

1

All of your 2-tuples in `(2,2),(3,3),(2,2)` have both elements equal. It would be worth giving an example with non-equal elements so that we can see which way round they are meant to work. Or if the two elements *must* be equal, then it would be better to specify it only once, i.e. `2,3,2`. – alani Jul 09 '20 at 00:30
@alaniwi OK, thank you for your advice, I just change the question – Nicolas H Jul 09 '20 at 00:36
3

`a.repeat([2,3,2],1).repeat([2,3,2],0)` – Paul Panzer Jul 09 '20 at 00:45
@PaulPanzer Nice. – alani Jul 09 '20 at 00:46
@PaulPanzer Amazing, thank you so much – Nicolas H Jul 09 '20 at 00:47

0 Answers0