scipy.linalg.lapack.dsytrd#

scipy.linalg.lapack.dsytrd(a, lower=0, lwork=max(n, 1), overwrite_a=0) = <flapack function dsytrd>#

Reduce a real symmetric matrix to real symmetric tridiagonal form by an orthogonal similarity transformation (LAPACK dsytrd).

Parameters:

andarray: Symmetric matrix of shape (n, n).
lowerint, optional: If nonzero, the lower triangle of a is referenced; otherwise the upper. Default is 0.
lworkint, optional: Size of the workspace. Default is max(n, 1). Use dsytrd_lwork for the optimal value.
overwrite_aint, optional: If nonzero, a may be overwritten in place. Default is 0.

Returns:

cndarray: The tridiagonal form together with the elementary reflectors that produced it, packed into a.
dndarray: Diagonal of the tridiagonal form, length n. Real for every flavor.
endarray: Off-diagonal, length n - 1. Real for every flavor.
taundarray: Scalar factors of the elementary reflectors that define Q.
infoint: 0 on success; if negative, the -info-th argument had an illegal value.