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

🦋 /home/abui...RC/cheev.f(3) 🦋

okay so bestie, welcome to the Library Functions Manual page for cheev.f(3) — manual name folded in right at the top like a lil bow 🎀. this is the LAPACK CHEEV situation and it’s giving complex Hermitian eigenvalues main character energy, no cap.

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🌸 NAME 🌸

the name situation is literally this source file path:

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

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✨ SYNOPSIS ✨

🫶 Functions/Subroutines 🫶

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

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💖 Function/Subroutine Documentation 💖

🧚 the signature 🧚

subroutine CHEEV (character jobz, character uplo, integer n, complex,
    dimension( lda, * ) a, integer lda, real, dimension( * ) w, complex,
    dimension( * ) work, integer lwork, real, dimension( * ) rwork, integer
    info)

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

🎯 Purpose 🎯

so the purpose is: CHEEV computes all eigenvalues and, optionally, eigenvectors of a complex Hermitian matrix A. that’s the whole assignment, bestie 💅.

🌈 Parameters 🌈

JOBZ

• JOBZ is CHARACTER*1.
  • = 'N': compute eigenvalues only.
  • = 'V': compute eigenvalues and eigenvectors.

UPLO

• UPLO is CHARACTER*1.
  • = 'U': upper triangle of A is stored.
  • = 'L': lower triangle of A is stored.

N

• N is INTEGER.
• The order of the matrix A. N >= 0.

A

• A is COMPLEX 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. ⚠️ like, actually destroyed, bestie.

LDA

• LDA is INTEGER.
• The leading dimension of the array A. LDA >= max(1,N).

W

• W is REAL array, dimension (N).
• If INFO = 0, the eigenvalues in ascending order.

WORK

• WORK is COMPLEX 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. LWORK >= max(1,2*N-1).
• For optimal efficiency, LWORK >= (NB+1)*N, where NB is the blocksize for CHETRD 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.

RWORK

• RWORK is REAL array, dimension (max(1, 3*N-2)).

INFO

• INFO is INTEGER.
  • = 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.

🫶 Author 🫶

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

📍 Definition at line 138 of file cheev.f.

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👑 Author 👑

Generated automatically by Doxygen for LAPACK from the source code.

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and that’s the whole page, bestie. sign-off time: this footer energy is LAPACK, Version 3.12.0, for /home/abui...RC/cheev.f(3) 🎀💖✨