`scipy.linalg._flapack:csyconv`

Signature

def csyconv(a, ipiv, lower = 0, way = 0, overwrite_a = 0)

Convert the Bunch-Kaufman factorization between its packed and its expanded storage (LAPACK csyconv).

a : ndarray: The factorization, as returned by sytrf.
ipiv : ndarray: Pivot indices from the Bunch-Kaufman factorization, 1-based exactly as sytrf/hetrf returned them -- this group shifts at neither end.
lower : int, optional: If nonzero, the lower triangle of a is referenced; otherwise the upper. Default is 0.
way : int, optional: 0 to convert the packed form into a plus e, 1 to revert. An integer here rather than the 'C'/'R' letter LAPACK takes. Default is 0.
overwrite_a : int, optional: If nonzero, a may be overwritten in place. Default is 0.

a : ndarray: The converted factorization.
e : ndarray: Off-diagonal entries of the 2x2 blocks of D, length n.
info : int: 0 on success; if negative, the -info-th argument had an illegal value.