Visible to Intel only — GUID: GUID-712C3EC7-47B0-413F-A4F9-9E00FCD07211
Visible to Intel only — GUID: GUID-712C3EC7-47B0-413F-A4F9-9E00FCD07211
?larrc
Computes the number of eigenvalues of the symmetric tridiagonal matrix.
Syntax
call slarrc( jobt, n, vl, vu, d, e, pivmin, eigcnt, lcnt, rcnt, info )
call dlarrc( jobt, n, vl, vu, d, e, pivmin, eigcnt, lcnt, rcnt, info )
Include Files
- mkl.fi
Description
The routine finds the number of eigenvalues of the symmetric tridiagonal matrix T or of its factorization L*D*LT in the specified interval.
Input Parameters
- jobt
-
CHARACTER*1.
= 'T': computes Sturm count for matrix T.= 'L': computes Sturm count for matrix L*D*LT.
- n
-
INTEGER.
The order of the matrix. (n > 1).
- vl,vu
-
REAL for slarrc
DOUBLE PRECISION for dlarrc
The lower and upper bounds for the eigenvalues. - d
-
REAL for slarrc
DOUBLE PRECISION for dlarrc
Array, DIMENSION (n).
If jobt= 'T': contains the n diagonal elements of the tridiagonal matrix T.
If jobt= 'L': contains the n diagonal elements of the diagonal matrix D.
- e
-
REAL for slarrc
DOUBLE PRECISION for dlarrc
Array, DIMENSION (n).
If jobt= 'T': contains the (n-1)offdiagonal elements of the matrix T.
If jobt= 'L': contains the (n-1)offdiagonal elements of the matrix L.
- pivmin
-
REAL for slarrc
DOUBLE PRECISION for dlarrc
The minimum pivot in the Sturm sequence for the matrix T.
Output Parameters
- eigcnt
- INTEGER.
The number of eigenvalues of the symmetric tridiagonal matrix T that are in the half-open interval (vl,vu].
- lcnt,rcnt
-
INTEGER.
The left and right negcounts of the interval.
- info
-
INTEGER.
Now it is not used and always is set to 0.