`scipy.linalg._decomp_ldl:_ldl_construct_tri_factor`

source: /scipy/linalg/_decomp_ldl.py :302

Signature

def _ldl_construct_tri_factor ( lu , swap_vec , pivs , lower = True )

Summary

Helper function to construct explicit outer factors of LDL factorization.

Extended Summary

If lower is True the permuted factors are multiplied as L(1)*L(2)*...*L(k). Otherwise, the permuted factors are multiplied as L(k)*...*L(2)*L(1). See LAPACK documentation for more details.

Parameters

lu : ndarray: The triangular array that is extracted from LAPACK routine call with ones on the diagonals.
swap_vec : ndarray: The array that defines the row swapping indices. If the kth entry is m then rows k,m are swapped. Notice that the mth entry is not necessarily k to avoid undoing the swapping.
pivs : ndarray: The array that defines the block diagonal structure returned by _ldl_sanitize_ipiv().
lower : bool, optional: The boolean to switch between lower and upper triangular structure.

Returns

lu : ndarray: The square outer factor which satisfies the L * D * L.T = A
perm : ndarray: The permutation vector that brings the lu to the triangular form

Notes

Note that the original argument "lu" is overwritten.

Aliases

scipy.linalg._decomp_ldl._ldl_construct_tri_factor