scipy.linalg.lapack.cgehrd#
- scipy.linalg.lapack.cgehrd(a, lo=0, hi=n - 1, lwork=max(n, 1), overwrite_a=0) = <flapack function cgehrd>#
Reduce a matrix to upper Hessenberg form (LAPACK
cgehrd).- Parameters:
- andarray
Square matrix of shape
(n, n).- loint, optional
Index of the first row/column to reduce, 0-based. Default is 0.
- hiint, optional
Index of the last row/column to reduce, 0-based. Default is
n - 1.- lworkint, optional
Size of the workspace. Default is
max(n, 1). Usegehrd_lworkfor the optimal value.- overwrite_aint, optional
If nonzero, a may be overwritten in place. Default is 0.
- Returns:
- htndarray
Upper Hessenberg form in the upper triangle and first subdiagonal; below that, the elementary reflectors that define
Q.- taundarray
Scalar factors of the elementary reflectors that define
Q.- infoint
0 on success; if negative, the
-info-th argument had an illegal value.