LAPACK
3.4.2
LAPACK: Linear Algebra PACKage

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Functions/Subroutines  
subroutine  cheev (JOBZ, UPLO, N, A, LDA, W, WORK, LWORK, RWORK, INFO) 
CHEEV computes the eigenvalues and, optionally, the left and/or right eigenvectors for HE matrices 
subroutine cheev  (  character  JOBZ, 
character  UPLO,  
integer  N,  
complex, dimension( lda, * )  A,  
integer  LDA,  
real, dimension( * )  W,  
complex, dimension( * )  WORK,  
integer  LWORK,  
real, dimension( * )  RWORK,  
integer  INFO  
) 
CHEEV computes the eigenvalues and, optionally, the left and/or right eigenvectors for HE matrices
Download CHEEV + dependencies [TGZ] [ZIP] [TXT]CHEEV computes all eigenvalues and, optionally, eigenvectors of a complex Hermitian matrix A.
[in]  JOBZ  JOBZ is CHARACTER*1 = 'N': Compute eigenvalues only; = 'V': Compute eigenvalues and eigenvectors. 
[in]  UPLO  UPLO is CHARACTER*1 = 'U': Upper triangle of A is stored; = 'L': Lower triangle of A is stored. 
[in]  N  N is INTEGER The order of the matrix A. N >= 0. 
[in,out]  A  A is COMPLEX array, dimension (LDA, N) On entry, the Hermitian matrix A. If UPLO = 'U', the leading NbyN upper triangular part of A contains the upper triangular part of the matrix A. If UPLO = 'L', the leading NbyN lower triangular part of A contains the lower triangular part of the matrix A. On exit, if JOBZ = 'V', then if INFO = 0, A contains the orthonormal eigenvectors of the matrix A. If JOBZ = 'N', then on exit the lower triangle (if UPLO='L') or the upper triangle (if UPLO='U') of A, including the diagonal, is destroyed. 
[in]  LDA  LDA is INTEGER The leading dimension of the array A. LDA >= max(1,N). 
[out]  W  W is REAL array, dimension (N) If INFO = 0, the eigenvalues in ascending order. 
[out]  WORK  WORK is COMPLEX array, dimension (MAX(1,LWORK)) On exit, if INFO = 0, WORK(1) returns the optimal LWORK. 
[in]  LWORK  LWORK is INTEGER The length of the array WORK. LWORK >= max(1,2*N1). For optimal efficiency, LWORK >= (NB+1)*N, where NB is the blocksize for CHETRD 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. 
[out]  RWORK  RWORK is REAL array, dimension (max(1, 3*N2)) 
[out]  INFO  INFO is INTEGER = 0: successful exit < 0: if INFO = i, the ith argument had an illegal value > 0: if INFO = i, the algorithm failed to converge; i offdiagonal elements of an intermediate tridiagonal form did not converge to zero. 
Definition at line 140 of file cheev.f.