Large sparse matrix LU decomposition

KK matrix is 305461 x 305461 sparse matrix

1)An out of memory error appears when running LU

is there a solution?

[L,U] = lu(KK)

2)What should I do to see the LU when using dk?

dK= decomposition(KK,'lu')

[L,U]= lu(dK) <== error : Error occurred while using:lu Invalid data type. The first argument must be double or single

Answer 1

[Christine Tobler]

If the call to lu runs out of memory, but the call to decomposition(__, 'lu') doesn't, likely the reason is that decomposition uses the five-output syntax of LU, which is much more efficient. You could try calling that syntax directly.

Decomposition doesn't support extracting the factors directly, just solving a linear system based on those factors which are internally stored in a quite different format.

[chan yeoung woo]

thank you~!! Then is there any way to use L and U separately?

[Christine Tobler]

It depends what you want to do with L and U. The five-output syntax returns L, U, and additional permutation and scaling matrices, perhaps you can adapt your usage of L and U to this case?