larrc#

Functions

void slarrc(
    const char*          jobt,
    const INT            n,
    const f32            vl,
    const f32            vu,
    const f32*  restrict D,
    const f32*  restrict E,
    const f32            pivmin,
          INT*           eigcnt,
          INT*           lcnt,
          INT*           rcnt,
          INT*           info
);
void slarrc(const char *jobt, const INT n, const f32 vl, const f32 vu, const f32 *restrict D, const f32 *restrict E, const f32 pivmin, INT *eigcnt, INT *lcnt, INT *rcnt, INT *info)#

SLARRC finds the number of eigenvalues of the symmetric tridiagonal matrix T that are in the interval (VL,VU] if JOBT = ‘T’, and of L D L^T if JOBT = ‘L’.

Parameters

in
jobt

CHARACTER*1. = ‘T’: Compute Sturm count for matrix T. = ‘L’: Compute Sturm count for matrix L D L^T.

in
n

The order of the matrix. N > 0.

in
vl

The lower bound for the eigenvalues.

in
vu

The upper bound for the eigenvalues.

in
D

Double precision array, dimension (N). JOBT = ‘T’: The N diagonal elements of the tridiagonal matrix T. JOBT = ‘L’: The N diagonal elements of the diagonal matrix D.

in
E

Double precision array, dimension (N). JOBT = ‘T’: The N-1 offdiagonal elements of the matrix T. JOBT = ‘L’: The N-1 offdiagonal elements of the matrix L.

in
pivmin

The minimum pivot in the Sturm sequence for T.

out
eigcnt

The number of eigenvalues in the interval (VL,VU].

out
lcnt

The left negcount of the interval.

out
rcnt

The right negcount of the interval.

out
info

  • = 0: successful exit.

Functions

void dlarrc(
    const char*          jobt,
    const INT            n,
    const f64            vl,
    const f64            vu,
    const f64*  restrict D,
    const f64*  restrict E,
    const f64            pivmin,
          INT*           eigcnt,
          INT*           lcnt,
          INT*           rcnt,
          INT*           info
);
void dlarrc(const char *jobt, const INT n, const f64 vl, const f64 vu, const f64 *restrict D, const f64 *restrict E, const f64 pivmin, INT *eigcnt, INT *lcnt, INT *rcnt, INT *info)#

DLARRC finds the number of eigenvalues of the symmetric tridiagonal matrix T that are in the interval (VL,VU] if JOBT = ‘T’, and of L D L^T if JOBT = ‘L’.

Parameters

in
jobt

CHARACTER*1. = ‘T’: Compute Sturm count for matrix T. = ‘L’: Compute Sturm count for matrix L D L^T.

in
n

The order of the matrix. N > 0.

in
vl

The lower bound for the eigenvalues.

in
vu

The upper bound for the eigenvalues.

in
D

Double precision array, dimension (N). JOBT = ‘T’: The N diagonal elements of the tridiagonal matrix T. JOBT = ‘L’: The N diagonal elements of the diagonal matrix D.

in
E

Double precision array, dimension (N). JOBT = ‘T’: The N-1 offdiagonal elements of the matrix T. JOBT = ‘L’: The N-1 offdiagonal elements of the matrix L.

in
pivmin

The minimum pivot in the Sturm sequence for T.

out
eigcnt

The number of eigenvalues in the interval (VL,VU].

out
lcnt

The left negcount of the interval.

out
rcnt

The right negcount of the interval.

out
info

  • = 0: successful exit.

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