/home/abui...RC/zheev.f(3)

🦋 NAME 🦋

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

okay so real talk: this is the manual page for zheev.f, and it lives in the LAPACK Library Functions Manual (section 3, bestie — the library functions section, iykyk). It's the source file for ZHEEV and honestly? she's iconic. 💅

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✨ SYNOPSIS ✨

🎀 Functions/Subroutines

• subroutine ZHEEV (jobz, uplo, n, a, lda, w, work, lwork, rwork, info) — ZHEEV computes the eigenvalues and, optionally, the left and/or right eigenvectors for HE matrices

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💖 Function/Subroutine Documentation 💖

okay here's the whole vibe, signature and all:

subroutine ZHEEV (character jobz, character uplo, integer n, complex*16,
    dimension( lda, * ) a, integer lda, double precision, dimension( * ) w,
    complex*16, dimension( * ) work, integer lwork, double precision,
    dimension( * ) rwork, integer info)

ZHEEV computes the eigenvalues and, optionally, the left and/or right eigenvectors for HE matrices. periodt. 👑

🌸 Purpose 🌸

ZHEEV computes all eigenvalues and, optionally, eigenvectors of a complex Hermitian matrix A. that's the whole job, and she does it. 🫶

💜 Parameters 💜

• JOBZ — JOBZ is CHARACTER*1, and it's giving "what do you want from me" energy:
  • = 'N': Compute eigenvalues only;
  • = 'V': Compute eigenvalues and eigenvectors.
• UPLO — UPLO is CHARACTER*1, aka which triangle of A you're storing:
  • = 'U': Upper triangle of A is stored;
  • = 'L': Lower triangle of A is stored.
• N — N is INTEGER, the order of the matrix A. Constraint: N >= 0. no negatives, bestie, it's not that kind of party. 🙈
• A — A is COMPLEX*16 array, dimension (LDA, N)
  • On entry, the Hermitian matrix A. If UPLO = 'U', the leading N-by-N upper triangular part of A contains the upper triangular part of the matrix A. If UPLO = 'L', the leading N-by-N lower triangular part of A contains the lower triangular part of the matrix A.
  • On exit, if JOBZ = 'V', then if INFO = 0, A contains the orthonormal eigenvectors of the matrix A.
  • If JOBZ = 'N', then on exit the lower triangle (if UPLO='L') or the upper triangle (if UPLO='U') of A, including the diagonal, is destroyed. 😭 so like, she ate your input, sorry, that's the deal.
• LDA — LDA is INTEGER, the leading dimension of the array A. Constraint: LDA >= max(1,N).
• W — W is DOUBLE PRECISION array, dimension (N). If INFO = 0, the eigenvalues in ascending order. she sorts them for you, that's called service. 💅
• WORK — WORK is COMPLEX*16 array, dimension (MAX(1,LWORK)). On exit, if INFO = 0, WORK(1) returns the optimal LWORK. 🎀
• LWORK — LWORK is INTEGER, the length of the array WORK. Constraint: LWORK >= max(1,2*N-1).
  • For optimal efficiency, LWORK >= (NB+1)*N, where NB is the blocksize for ZHETRD returned by ILAENV.
  • If LWORK = -1, then a workspace query is assumed; the routine only calculates the optimal size of the WORK array, returns this value as the first entry of the WORK array, and no error message related to LWORK is issued by XERBLA. it's the "just asking, not committing" option, we love a low-stakes queen. ✨
• RWORK — RWORK is DOUBLE PRECISION array, dimension (max(1, 3*N-2))
• INFO — INFO is INTEGER, the receipts:
  • = 0: successful exit 🎉
  • < 0: if INFO = -i, the i-th argument had an illegal value
  • > 0: if INFO = i, the algorithm failed to converge; i off-diagonal elements of an intermediate tridiagonal form did not converge to zero.

fr fr, that last one matters: when INFO > 0 she did NOT finish converging, so don't trust those results as gospel, bestie.

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👑 Author 👑

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

Definition at line 138 of file zheev.f.

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🌈 Author 🌈

Generated automatically by Doxygen for LAPACK from the source code. (yes, the page has two Author sections — that's not a glitch, that's just how she's built. 💀)

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and that's the whole page, bestie — go forth and diagonalize responsibly. stay slay, stay Hermitian. 💖✨

LAPACK, Version 3.12.0 🦋 — doc auto-generated by Doxygen for LAPACK from the source code, mwah 💋