heevx(3)

📦

version 3.12.1 · 9 versions

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, in arch rolling

heevx(3)

From the Library Functions Manual, bestie — yes, that heevx(3) header. 💖

🌸 NAME 🌸

heevx — {he,sy}evx: eig, bisection

✨ SYNOPSIS ✨

🎀 Functions 🎀

💅 `cheevx`

subroutine cheevx (jobz, range, uplo, n, a, lda, vl, vu, il, iu, abstol,
    m, w, z, ldz, work, lwork, rwork, iwork, ifail, info)

CHEEVX computes the eigenvalues and, optionally, the left and/or right eigenvectors for HE matrices. Slay.

🦋 `dsyevx`

subroutine dsyevx (jobz, range, uplo, n, a, lda, vl, vu, il, iu, abstol,
    m, w, z, ldz, work, lwork, iwork, ifail, info)

DSYEVX computes the eigenvalues and, optionally, the left and/or right eigenvectors for SY matrices.

🍓 `ssyevx`

subroutine ssyevx (jobz, range, uplo, n, a, lda, vl, vu, il, iu, abstol,
    m, w, z, ldz, work, lwork, iwork, ifail, info)

SSYEVX computes the eigenvalues and, optionally, the left and/or right eigenvectors for SY matrices.

🌈 `zheevx`

subroutine zheevx (jobz, range, uplo, n, a, lda, vl, vu, il, iu, abstol,
    m, w, z, ldz, work, lwork, rwork, iwork, ifail, info)

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

💜 Detailed Description 💜

Okay bestie, this is where the detailed function docs live. Buckle up. 🎀

🌟 Function Documentation 🌟

💖 `cheevx` 💖

subroutine cheevx (character jobz, character range, character uplo, integer
    n, complex, dimension( lda, * ) a, integer lda, real vl, real vu,
    integer il, integer iu, real abstol, integer m, real, dimension( * ) w,
    complex, dimension( ldz, * ) z, integer ldz, complex, dimension( * )
    work, integer lwork, real, dimension( * ) rwork, integer, dimension( * )
    iwork, integer, dimension( * ) ifail, integer info)

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

Purpose:

CHEEVX computes selected eigenvalues and, optionally, eigenvectors of a complex Hermitian matrix A. Eigenvalues and eigenvectors can be selected by specifying either a range of values or a range of indices for the desired eigenvalues. Main character behavior, honestly.

Parameters

JOBZ — JOBZ is CHARACTER*1.
- = 'N': Compute eigenvalues only;
- = 'V': Compute eigenvalues and eigenvectors.
RANGE — RANGE is CHARACTER*1.
- = 'A': all eigenvalues will be found.
- = 'V': all eigenvalues in the half-open interval (VL,VU] will be found.
- = 'I': the IL-th through IU-th eigenvalues will be found.
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, the lower triangle (if UPLO='L') or the upper triangle (if UPLO='U') of A, including the diagonal, is destroyed. Gone. Poof. Bestie, it's destroyed.
LDA — LDA is INTEGER. The leading dimension of the array A. LDA >= max(1,N).
VL — VL is REAL. If RANGE='V', the lower bound of the interval to be searched for eigenvalues. VL < VU. Not referenced if RANGE = 'A' or 'I'.
VU — VU is REAL. If RANGE='V', the upper bound of the interval to be searched for eigenvalues. VL < VU. Not referenced if RANGE = 'A' or 'I'.
IL — IL is INTEGER. If RANGE='I', the index of the smallest eigenvalue to be returned. 1 <= IL <= IU <= N, if N > 0; IL = 1 and IU = 0 if N = 0. Not referenced if RANGE = 'A' or 'V'.
IU — IU is INTEGER. If RANGE='I', the index of the largest eigenvalue to be returned. 1 <= IL <= IU <= N, if N > 0; IL = 1 and IU = 0 if N = 0. Not referenced if RANGE = 'A' or 'V'.
ABSTOL — ABSTOL is REAL. The absolute error tolerance for the eigenvalues. An approximate eigenvalue is accepted as converged when it is determined to lie in an interval [a,b] of width less than or equal to

ABSTOL + EPS *   max( |a|,|b| ) ,

where EPS is the machine precision. If ABSTOL is less than or equal to zero, then EPS*|T| will be used in its place, where |T| is the 1-norm of the tridiagonal matrix obtained by reducing A to tridiagonal form.

Eigenvalues will be computed most accurately when ABSTOL is set to twice the underflow threshold 2*SLAMCH('S'), not zero. If this routine returns with INFO>0, indicating that some eigenvectors did not converge, try setting ABSTOL to 2*SLAMCH('S').

See by Demmel and Kahan, LAPACK Working Note #3.

M — M is INTEGER. The total number of eigenvalues found. 0 <= M <= N. If RANGE = 'A', M = N, and if RANGE = 'I', M = IU-IL+1.
W — W is REAL array, dimension (N). On normal exit, the first M elements contain the selected eigenvalues in ascending order.
Z — Z is COMPLEX array, dimension (LDZ, max(1,M)). If JOBZ = 'V', then if INFO = 0, the first M columns of Z contain the orthonormal eigenvectors of the matrix A corresponding to the selected eigenvalues, with the i-th column of Z holding the eigenvector associated with W(i). If an eigenvector fails to converge, then that column of Z contains the latest approximation to the eigenvector, and the index of the eigenvector is returned in IFAIL. If JOBZ = 'N', then Z is not referenced. Note: the user must ensure that at least max(1,M) columns are supplied in the array Z; if RANGE = 'V', the exact value of M is not known in advance and an upper bound must be used.
LDZ — LDZ is INTEGER. The leading dimension of the array Z. LDZ >= 1, and if JOBZ = 'V', LDZ >= max(1,N).
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 >= 1, when N <= 1; otherwise 2*N. For optimal efficiency, LWORK >= (NB+1)*N, where NB is the max of the blocksize for CHETRD and for CUNMTR as 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 (7*N).
IWORK — IWORK is INTEGER array, dimension (5*N).
IFAIL — IFAIL is INTEGER array, dimension (N). If JOBZ = 'V', then if INFO = 0, the first M elements of IFAIL are zero. If INFO > 0, then IFAIL contains the indices of the eigenvectors that failed to converge. If JOBZ = 'N', then IFAIL is not referenced.
INFO — INFO is INTEGER.
- = 0: successful exit
- < 0: if INFO = -i, the i-th argument had an illegal value
- > 0: if INFO = i, then i eigenvectors failed to converge. Their indices are stored in array IFAIL.

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 256 of file cheevx.f.

💙 `dsyevx` 💙

subroutine dsyevx (character jobz, character range, character uplo, integer
    n, double precision, dimension( lda, * ) a, integer lda, double
    precision vl, double precision vu, integer il, integer iu, double
    precision abstol, integer m, double precision, dimension( * ) w, double
    precision, dimension( ldz, * ) z, integer ldz, double precision,
    dimension( * ) work, integer lwork, integer, dimension( * ) iwork,
    integer, dimension( * ) ifail, integer info)

DSYEVX computes the eigenvalues and, optionally, the left and/or right eigenvectors for SY matrices.

Purpose:

DSYEVX computes selected eigenvalues and, optionally, eigenvectors of a real symmetric matrix A. Eigenvalues and eigenvectors can be selected by specifying either a range of values or a range of indices for the desired eigenvalues.

Parameters

JOBZ — JOBZ is CHARACTER*1.
- = 'N': Compute eigenvalues only;
- = 'V': Compute eigenvalues and eigenvectors.
RANGE — RANGE is CHARACTER*1.
- = 'A': all eigenvalues will be found.
- = 'V': all eigenvalues in the half-open interval (VL,VU] will be found.
- = 'I': the IL-th through IU-th eigenvalues will be found.
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 — this is exactly where the source chunk cuts off, bestie — the rest of A's description picks up in the next part.

Okay so A — it’s a DOUBLE PRECISION array, dimension (LDA, N). On entry, it’s the symmetric 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, the lower triangle (if UPLO='L') or the upper triangle (if UPLO='U') of A, including the diagonal, is destroyed.

bestie, “destroyed” is not a vibe — that means the triangle and diagonal are gone. do not expect A to come back looking cute. 😭

LDA — LDA is INTEGER. The leading dimension of the array A. LDA >= max(1,N).
VL — VL is DOUBLE PRECISION. If RANGE='V', this is the lower bound of the interval to be searched for eigenvalues. VL < VU. Not referenced if RANGE = 'A' or 'I'.
VU — VU is DOUBLE PRECISION. If RANGE='V', this is the upper bound of the interval to be searched for eigenvalues. VL < VU. Not referenced if RANGE = 'A' or 'I'.
IL — IL is INTEGER. If RANGE='I', this is the index of the smallest eigenvalue to be returned. 1 <= IL <= IU <= N, if N > 0; IL = 1 and IU = 0 if N = 0. Not referenced if RANGE = 'A' or 'V'.
IU — IU is INTEGER. If RANGE='I', this is the index of the largest eigenvalue to be returned. 1 <= IL <= IU <= N, if N > 0; IL = 1 and IU = 0 if N = 0. Not referenced if RANGE = 'A' or 'V'.
ABSTOL — ABSTOL is DOUBLE PRECISION. It’s the absolute error tolerance for the eigenvalues. An approximate eigenvalue is accepted as converged when it’s determined to lie in an interval [a,b] of width less than or equal to

ABSTOL + EPS *   max( |a|,|b| ) ,

Eigenvalues will be computed most accurately when ABSTOL is set to twice the underflow threshold 2*DLAMCH('S'), not zero. If this routine returns with INFO>0, indicating that some eigenvectors did not converge, try setting ABSTOL to 2*DLAMCH('S').

Also: See by Demmel and Kahan, LAPACK Working Note #3.

M — M is INTEGER. The total number of eigenvalues found. 0 <= M <= N. If RANGE = 'A', M = N, and if RANGE = 'I', M = IU-IL+1.
W — W is DOUBLE PRECISION array, dimension (N). On normal exit, the first M elements contain the selected eigenvalues in ascending order.
Z — Z is DOUBLE PRECISION array, dimension (LDZ, max(1,M)). If JOBZ = 'V', then if INFO = 0, the first M columns of Z contain the orthonormal eigenvectors of the matrix A corresponding to the selected eigenvalues, with the i-th column of Z holding the eigenvector associated with W(i). If an eigenvector fails to converge, then that column of Z contains the latest approximation to the eigenvector, and the index of the eigenvector is returned in IFAIL. If JOBZ = 'N', then Z is not referenced.

Note: you must ensure that at least max(1,M) columns are supplied in the array Z; if RANGE = 'V', the exact value of M is not known in advance and an upper bound must be used.

LDZ — LDZ is INTEGER. The leading dimension of the array Z. LDZ >= 1, and if JOBZ = 'V', LDZ >= max(1,N).
WORK — WORK is DOUBLE PRECISION 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 >= 1, when N <= 1; otherwise 8*N. For optimal efficiency, LWORK >= (NB+3)*N, where NB is the max of the blocksize for DSYTRD and DORMTR returned by ILAENV.

IWORK — IWORK is INTEGER array, dimension (5*N).
IFAIL — IFAIL is INTEGER array, dimension (N). If JOBZ = 'V', then if INFO = 0, the first M elements of IFAIL are zero. If INFO > 0, then IFAIL contains the indices of the eigenvectors that failed to converge. If JOBZ = 'N', then IFAIL is not referenced.
INFO — INFO is INTEGER.

= 0:  successful exit
< 0:  if INFO = -i, the i-th argument had an illegal value
> 0:  if INFO = i, then i eigenvectors failed to converge.
      Their indices are stored in array IFAIL.

👑 Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 250 of file dsyevx.f.

🦋 subroutine ssyevx

subroutine ssyevx (character jobz, character range, character uplo, integer
    n, real, dimension( lda, * ) a, integer lda, real vl, real vu, integer
    il, integer iu, real abstol, integer m, real, dimension( * ) w, real,
    dimension( ldz, * ) z, integer ldz, real, dimension( * ) work, integer
    lwork, integer, dimension( * ) iwork, integer, dimension( * ) ifail,
    integer info)

SSYEVX computes the eigenvalues and, optionally, the left and/or right eigenvectors for SY matrices.

🌸 Purpose

Okay so SSYEVX computes selected eigenvalues and, optionally, eigenvectors of a real symmetric matrix A. You can select eigenvalues and eigenvectors by specifying either a range of values or a range of indices for the desired eigenvalues.

💅 Parameters

JOBZ — JOBZ is CHARACTER*1.
- = 'N': Compute eigenvalues only;
- = 'V': Compute eigenvalues and eigenvectors.
RANGE — RANGE is CHARACTER*1.
- = 'A': all eigenvalues will be found.
- = 'V': all eigenvalues in the half-open interval (VL,VU] will be found.
- = 'I': the IL-th through IU-th eigenvalues will be found.
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 REAL array, dimension (LDA, N). On entry, it’s the symmetric 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, the lower triangle (if UPLO='L') or the upper triangle (if UPLO='U') of A, including the diagonal, is destroyed.
LDA — LDA is INTEGER. The leading dimension of the array A. LDA >= max(1,N).
VL — VL is REAL. If RANGE='V', this is the lower bound of the interval to be searched for eigenvalues. VL < VU. Not referenced if RANGE = 'A' or 'I'.
VU — VU is REAL. If RANGE='V', this is the upper bound of the interval to be searched for eigenvalues. VL < VU. Not referenced if RANGE = 'A' or 'I'.
IL — IL is INTEGER. If RANGE='I', this is the index of the smallest eigenvalue to be returned. 1 <= IL <= IU <= N, if N > 0; IL = 1 and IU = 0 if N = 0. Not referenced if RANGE = 'A' or 'V'.
IU — IU is INTEGER. If RANGE='I', this is the index of the largest eigenvalue to be returned. 1 <= IL <= IU <= N, if N > 0; IL = 1 and IU = 0 if N = 0. Not referenced if RANGE = 'A' or 'V'.
ABSTOL — ABSTOL is REAL. It’s the absolute error tolerance for the eigenvalues. An approximate eigenvalue is accepted as converged when it’s determined to lie in an interval [a,b] of width less than or equal to

ABSTOL + EPS *   max( |a|,|b| ) ,

Also: See by Demmel and Kahan, LAPACK Working Note #3.

M — M is INTEGER. The total number of eigenvalues found. 0 <= M <= N. If RANGE = 'A', M = N, and if RANGE = 'I', M = IU-IL+1.
W —
W — bestie, this is the glow-up zone: W is REAL array, dimension (N). On normal exit, the first M elements contain the selected eigenvalues in ascending order. ✨
Z — Z is REAL array, dimension (LDZ, max(1,M)). If JOBZ = 'V', then if INFO = 0, the first M columns of Z contain the orthonormal eigenvectors of the matrix A corresponding to the selected eigenvalues, with the i-th column of Z holding the eigenvector associated with W(i). If an eigenvector fails to converge, then that column of Z contains the latest approximation to the eigenvector, and the index of the eigenvector is returned in IFAIL. If JOBZ = 'N', then Z is not referenced. Note: the user must ensure that at least max(1,M) columns are supplied in the array Z; if RANGE = 'V', the exact value of M is not known in advance and an upper bound must be used. 🫶
LDZ — LDZ is INTEGER. The leading dimension of the array Z. LDZ >= 1, and if JOBZ = 'V', LDZ >= max(1,N). 💅
WORK — WORK is REAL 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 >= 1, when N <= 1; otherwise 8*N. For optimal efficiency, LWORK >= (NB+3)*N, where NB is the max of the blocksize for SSYTRD and SORMTR 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. 🔥
IWORK — IWORK is INTEGER array, dimension (5*N). 🎀
IFAIL — IFAIL is INTEGER array, dimension (N). If JOBZ = 'V', then if INFO = 0, the first M elements of IFAIL are zero. If INFO > 0, then IFAIL contains the indices of the eigenvectors that failed to converge. If JOBZ = 'N', then IFAIL is not referenced. 🦋
INFO — INFO is INTEGER:
- = 0: successful exit.
- < 0: if INFO = -i, the i-th argument had an illegal value.
- > 0: if INFO = i, then i eigenvectors failed to converge. Their indices are stored in array IFAIL. 😭

🌟 Author

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

Definition at line 250 of file ssyevx.f.

🦋 subroutine `zheevx` 🦋

   subroutine zheevx (character jobz, character range, character uplo, integer
       n, complex*16, dimension( lda, * ) a, integer lda, double precision vl,
       double precision vu, integer il, integer iu, double precision abstol,
       integer m, double precision, dimension( * ) w, complex*16, dimension(
       ldz, * ) z, integer ldz, complex*16, dimension( * ) work, integer lwork,
       double precision, dimension( * ) rwork, integer, dimension( * ) iwork,
       integer, dimension( * ) ifail, integer info)

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

🎯 Purpose

ZHEEVX computes selected eigenvalues and, optionally, eigenvectors of a complex Hermitian matrix A. Eigenvalues and eigenvectors can be selected by specifying either a range of values or a range of indices for the desired eigenvalues. No cap, that's the whole vibe. 💜

🌸 Parameters

JOBZ — JOBZ is CHARACTER*1:
- = 'N': compute eigenvalues only;
- = 'V': compute eigenvalues and eigenvectors. ✨
RANGE — RANGE is CHARACTER*1:
- = 'A': all eigenvalues will be found.
- = 'V': all eigenvalues in the half-open interval (VL,VU] will be found.
- = 'I': the IL-th through IU-th eigenvalues will be found. 🎀
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*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, the lower triangle (if UPLO='L') or the upper triangle (if UPLO='U') of A, including the diagonal, is destroyed. Not me being dramatic — that's literally what the routine says. 💀

LDA — LDA is INTEGER. The leading dimension of the array A. LDA >= max(1,N). 🌈
VL — VL is DOUBLE PRECISION. If RANGE='V', the lower bound of the interval to be searched for eigenvalues. VL < VU. Not referenced if RANGE = 'A' or 'I'. 🌸
VU — VU is DOUBLE PRECISION. If RANGE='V', the upper bound of the interval to be searched for eigenvalues. VL < VU. Not referenced if RANGE = 'A' or 'I'. 🌸
IL — IL is INTEGER. If RANGE='I', the index of the smallest eigenvalue to be returned. 1 <= IL <= IU <= N, if N > 0; IL = 1 and IU = 0 if N = 0. Not referenced if RANGE = 'A' or 'V'. 🫶
IU — IU is INTEGER. If RANGE='I', the index of the largest eigenvalue to be returned. 1 <= IL <= IU <= N, if N > 0; IL = 1 and IU = 0 if N = 0. Not referenced if RANGE = 'A' or 'V'. 🫶
ABSTOL — ABSTOL is DOUBLE PRECISION. The absolute error tolerance for the eigenvalues. An approximate eigenvalue is accepted as converged when it is determined to lie in an interval [a,b] of width less than or equal to

ABSTOL + EPS *   max( |a|,|b| ) ,

M — M is INTEGER. The total number of eigenvalues found. 0 <= M <= N. If RANGE = 'A', M = N, and if RANGE = 'I', M = IU-IL+1. 💖
W — W is DOUBLE PRECISION array, dimension (N). On normal exit, the first M elements contain the selected eigenvalues in ascending order. ✨
Z — Z is COMPLEX*16 array, dimension (LDZ, max(1,M)). If JOBZ = 'V', then if INFO = 0, the first M columns of Z contain the orthonormal eigenvectors of the matrix A corresponding to the selected eigenvalues, with the i-th column of Z holding the eigenvector associated with W(i). If an eigenvector fails to converge, then that column of Z contains the latest approximation to the eigenvector, and the index of the eigenvector is returned in IFAIL. If JOBZ = 'N', then Z is not referenced. Note: the user must ensure that at least max(1,M) columns are supplied in the array Z; if RANGE = 'V', the exact value of M is not known in advance and an upper bound must be used. 🫶
LDZ — LDZ is INTEGER. The leading dimension of the array Z. LDZ >= 1, and if JOBZ = 'V', LDZ >= max(1,N). 💅
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. LWORK >= 1, when N <= 1; otherwise 2*N. For optimal efficiency, LWORK >= (NB+1)*N, where NB is the max of the blocksize for ZHETRD and for ZUNMTR as 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 DOUBLE PRECISION array, dimension (7*N). 🎀
IWORK — IWORK is INTEGER array, dimension (5*N). 🎀
IFAIL — IFAIL is INTEGER array, dimension (N). If JOBZ = 'V', then if INFO = 0, the first M elements of IFAIL are zero. If INFO > 0, then IFAIL contains the indices of the eigenvectors that failed to converge. If JOBZ = 'N', then IFAIL is not referenced. 🦋
INFO — INFO is INTEGER:
- = 0: successful exit.
- < 0: if INFO = -i, the i-th argument had an illegal value.
- > 0: if INFO = i, then i eigenvectors failed to converge. Their indices are stored in array IFAIL. 😭

🌟 Author

Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd. — also on the author list, bestie 💜

And literally right after that, the receipts: Definition at line 256 of file zheevx.f. (that's the Fortran source doing its thing, iykyk 🫶)

🌸 Author 🌸

This whole page? Generated automatically by Doxygen for LAPACK from the source code. So no human sat there hand-typing it — the docs wrote themselves, main character behaviour fr fr ✨ Not me being obsessed with an auto-generated manpage 💅

Okay so that's a wrap, bestie! This was heevx(3) from LAPACK, Version 3.12.0 — the version and source are the whole footer vibe, so go off and compute those selected eigenvalues and eigenvectors of a complex Hermitian matrix with confidence 👑💖

Bye bestie, slay your linear algebra 🎀🦋

📦 where this page comes from

arch rolling: lapack-doc 3.12.1-2 · custom
💖 girlified by deepseek-ai/DeepSeek-V4.1-Flash-1017 on 2026-11-04: a language model's rewrite of the original, under its terms

heevx(3)

heevx(3)

🌸 NAME 🌸

✨ SYNOPSIS ✨

🎀 Functions 🎀

💅 cheevx

🦋 dsyevx

🍓 ssyevx

🌈 zheevx

💜 Detailed Description 💜

🌟 Function Documentation 🌟

💖 cheevx 💖

💙 dsyevx 💙

👑 Author

🦋 subroutine ssyevx

🌸 Purpose

💅 Parameters

🌟 Author

🦋 subroutine zheevx 🦋

🎯 Purpose

🌸 Parameters

🌟 Author

🌸 Author 🌸

💅 `cheevx`

🦋 `dsyevx`

🍓 `ssyevx`

🌈 `zheevx`

💖 `cheevx` 💖

💙 `dsyevx` 💙

🦋 subroutine `zheevx` 🦋