LAPACK 3.12.0
LAPACK: Linear Algebra PACKage

Functions  
subroutine  clatrd (uplo, n, nb, a, lda, e, tau, w, ldw) 
CLATRD reduces the first nb rows and columns of a symmetric/Hermitian matrix A to real tridiagonal form by an unitary similarity transformation.  
subroutine  dlatrd (uplo, n, nb, a, lda, e, tau, w, ldw) 
DLATRD reduces the first nb rows and columns of a symmetric/Hermitian matrix A to real tridiagonal form by an orthogonal similarity transformation.  
subroutine  slatrd (uplo, n, nb, a, lda, e, tau, w, ldw) 
SLATRD reduces the first nb rows and columns of a symmetric/Hermitian matrix A to real tridiagonal form by an orthogonal similarity transformation.  
subroutine  zlatrd (uplo, n, nb, a, lda, e, tau, w, ldw) 
ZLATRD reduces the first nb rows and columns of a symmetric/Hermitian matrix A to real tridiagonal form by an unitary similarity transformation.  