sbev_2stage#

Functions

void ssbev_2stage(
    const char*          jobz,
    const char*          uplo,
    const INT            n,
    const INT            kd,
          f32*  restrict AB,
    const INT            ldab,
          f32*  restrict W,
          f32*  restrict Z,
    const INT            ldz,
          f32*  restrict work,
    const INT            lwork,
          INT*           info
);
void ssbev_2stage(const char *jobz, const char *uplo, const INT n, const INT kd, f32 *restrict AB, const INT ldab, f32 *restrict W, f32 *restrict Z, const INT ldz, f32 *restrict work, const INT lwork, INT *info)#

SSBEV_2STAGE computes all the eigenvalues and, optionally, eigenvectors of a real symmetric band matrix A using the 2-stage technique for the reduction to tridiagonal.

Parameters

in
jobz

= ‘N’: eigenvalues only; = ‘V’: not available in this release.

in
uplo

= ‘U’: upper triangle stored; = ‘L’: lower triangle stored

in
n

The order of the matrix A. n >= 0.

in
kd

Number of super/sub-diagonals. kd >= 0.

inout
AB

Band matrix, overwritten on exit.

in
ldab

Leading dimension of AB. ldab >= kd+1.

out
W

Eigenvalues in ascending order.

out
Z

Eigenvectors if jobz=’V’; not referenced if jobz=’N’.

in
ldz

Leading dimension of Z. ldz >= 1, or ldz >= n if jobz=’V’.

out
work

Workspace. On exit, work[0] = optimal LWORK.

in
lwork

Length of work. If -1, workspace query.

out
info

  • = 0: success; < 0: illegal argument; > 0: convergence failure.

Functions

void dsbev_2stage(
    const char*          jobz,
    const char*          uplo,
    const INT            n,
    const INT            kd,
          f64*  restrict AB,
    const INT            ldab,
          f64*  restrict W,
          f64*  restrict Z,
    const INT            ldz,
          f64*  restrict work,
    const INT            lwork,
          INT*           info
);
void dsbev_2stage(const char *jobz, const char *uplo, const INT n, const INT kd, f64 *restrict AB, const INT ldab, f64 *restrict W, f64 *restrict Z, const INT ldz, f64 *restrict work, const INT lwork, INT *info)#

DSBEV_2STAGE computes all the eigenvalues and, optionally, eigenvectors of a real symmetric band matrix A using the 2-stage technique for the reduction to tridiagonal.

Parameters

in
jobz

= ‘N’: eigenvalues only; = ‘V’: not available in this release.

in
uplo

= ‘U’: upper triangle stored; = ‘L’: lower triangle stored

in
n

The order of the matrix A. n >= 0.

in
kd

Number of super/sub-diagonals. kd >= 0.

inout
AB

Band matrix, overwritten on exit.

in
ldab

Leading dimension of AB. ldab >= kd+1.

out
W

Eigenvalues in ascending order.

out
Z

Eigenvectors if jobz=’V’; not referenced if jobz=’N’.

in
ldz

Leading dimension of Z. ldz >= 1, or ldz >= n if jobz=’V’.

out
work

Workspace. On exit, work[0] = optimal LWORK.

in
lwork

Length of work. If -1, workspace query.

out
info

  • = 0: success; < 0: illegal argument; > 0: convergence failure.

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