LAPACK
3.4.2
LAPACK: Linear Algebra PACKage

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Functions/Subroutines  
subroutine  ssbev (JOBZ, UPLO, N, KD, AB, LDAB, W, Z, LDZ, WORK, INFO) 
SSBEV computes the eigenvalues and, optionally, the left and/or right eigenvectors for OTHER matrices 
subroutine ssbev  (  character  JOBZ, 
character  UPLO,  
integer  N,  
integer  KD,  
real, dimension( ldab, * )  AB,  
integer  LDAB,  
real, dimension( * )  W,  
real, dimension( ldz, * )  Z,  
integer  LDZ,  
real, dimension( * )  WORK,  
integer  INFO  
) 
SSBEV computes the eigenvalues and, optionally, the left and/or right eigenvectors for OTHER matrices
Download SSBEV + dependencies [TGZ] [ZIP] [TXT]SSBEV computes all the eigenvalues and, optionally, eigenvectors of a real symmetric band 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]  KD  KD is INTEGER The number of superdiagonals of the matrix A if UPLO = 'U', or the number of subdiagonals if UPLO = 'L'. KD >= 0. 
[in,out]  AB  AB is REAL array, dimension (LDAB, N) On entry, the upper or lower triangle of the symmetric band matrix A, stored in the first KD+1 rows of the array. The jth column of A is stored in the jth column of the array AB as follows: if UPLO = 'U', AB(kd+1+ij,j) = A(i,j) for max(1,jkd)<=i<=j; if UPLO = 'L', AB(1+ij,j) = A(i,j) for j<=i<=min(n,j+kd). On exit, AB is overwritten by values generated during the reduction to tridiagonal form. If UPLO = 'U', the first superdiagonal and the diagonal of the tridiagonal matrix T are returned in rows KD and KD+1 of AB, and if UPLO = 'L', the diagonal and first subdiagonal of T are returned in the first two rows of AB. 
[in]  LDAB  LDAB is INTEGER The leading dimension of the array AB. LDAB >= KD + 1. 
[out]  W  W is REAL array, dimension (N) If INFO = 0, the eigenvalues in ascending order. 
[out]  Z  Z is REAL array, dimension (LDZ, N) If JOBZ = 'V', then if INFO = 0, Z contains the orthonormal eigenvectors of the matrix A, with the ith column of Z holding the eigenvector associated with W(i). If JOBZ = 'N', then Z is not referenced. 
[in]  LDZ  LDZ is INTEGER The leading dimension of the array Z. LDZ >= 1, and if JOBZ = 'V', LDZ >= max(1,N). 
[out]  WORK  WORK 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 146 of file ssbev.f.