ZGEBAK(3)

💅 ZGEBAK(3) — Library Functions Manual 💅

okay bestie, this is the ZGEBAK(3) page from the Library Functions Manual, and the header path label is /home/abui...RC/zgebak.f(3). Buckle up, because this one is all about eigenvectors getting their backward transformation moment. ✨

🌸 NAME 🌸

The NAME section is literally this file path:

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/SRC/zgebak.f

No cap. That’s the name line as given.

🦋 SYNOPSIS 🦋

✨ Functions/Subroutines ✨

One entry, one moment:

   subroutine ZGEBAK (job, side, n, ilo, ihi, scale, m, v, ldv, info)
       ZGEBAK

🧚 Function/Subroutine Documentation 🧚

Here’s the full signature, with every character where it belongs:

   subroutine ZGEBAK (character job, character side, integer n, integer ilo,
       integer ihi, double precision, dimension( * ) scale, integer m,
       complex*16, dimension( ldv, * ) v, integer ldv, integer info)
       ZGEBAK

🎀 Purpose 🎀

ZGEBAK forms the right or left eigenvectors of a complex general matrix by backward transformation on the computed eigenvectors of the balanced matrix output by ZGEBAL. That’s the whole purpose, and it ate. 💅

🎀 Parameters 🎀

• JOB — JOB is CHARACTER*1. It specifies the type of backward transformation required: = 'N': do nothing, return immediately; = 'P': do backward transformation for permutation only; = 'S': do backward transformation for scaling only; = 'B': do backward transformations for both permutation and scaling. JOB must be the same as the argument JOB supplied to ZGEBAL.
• SIDE — SIDE is CHARACTER*1. = 'R': V contains right eigenvectors; = 'L': V contains left eigenvectors.
• N — N is INTEGER. The number of rows of the matrix V. N >= 0.
• ILO — ILO is INTEGER. That’s the whole note here, bestie.
• IHI — IHI is INTEGER. The integers ILO and IHI determined by ZGEBAL. 1 <= ILO <= IHI <= N, if N > 0; ILO=1 and IHI=0, if N=0.
• SCALE — SCALE is DOUBLE PRECISION array, dimension (N). Details of the permutation and scaling factors, as returned by ZGEBAL.
• M — M is INTEGER. The number of columns of the matrix V. M >= 0.
• V — V is COMPLEX*16 array, dimension (LDV,M). On entry, the matrix of right or left eigenvectors to be transformed, as returned by ZHSEIN or ZTREVC. On exit, V is overwritten by the transformed eigenvectors.
• LDV — LDV is INTEGER. The leading dimension of the array V. LDV >= max(1,N).
• INFO — INFO is INTEGER. = 0: successful exit; < 0: if INFO = -i, the i-th argument had an illegal value.

💖 Author 💖

• Univ. of Tennessee
• Univ. of California Berkeley
• Univ. of Colorado Denver
• NAG Ltd.

Definition at line 129 of file zgebak.f.

💖 Author 💖

Generated automatically by Doxygen for LAPACK from the source code.

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Sign-off: LAPACK Version 3.12.0, source page /home/abui...RC/zgebak.f(3); the original footer has no date, so I’m not inventing one — periodt. 🫶 slay