
NAMEzlaed0.f SYNOPSISFunctions/Subroutinessubroutine zlaed0 (QSIZ, N, D, E, Q, LDQ, QSTORE, LDQS, RWORK, IWORK, INFO) Function/Subroutine Documentationsubroutine zlaed0 (integerQSIZ, integerN, double precision, dimension( * )D, double precision, dimension( * )E, complex*16, dimension( ldq, * )Q, integerLDQ, complex*16, dimension( ldqs, * )QSTORE, integerLDQS, double precision, dimension( * )RWORK, integer, dimension( * )IWORK, integerINFO)ZLAED0 used by sstedc. Computes all eigenvalues and corresponding eigenvectors of an unreduced symmetric tridiagonal matrix using the divide and conquer method. Purpose:Using the divide and conquer method, ZLAED0 computes all eigenvalues of a symmetric tridiagonal matrix which is one diagonal block of those from reducing a dense or band Hermitian matrix and corresponding eigenvectors of the dense or band matrix. QSIZ
Author:
QSIZ is INTEGER The dimension of the unitary matrix used to reduce the full matrix to tridiagonal form. QSIZ >= N if ICOMPQ = 1.N N is INTEGER The dimension of the symmetric tridiagonal matrix. N >= 0.D D is DOUBLE PRECISION array, dimension (N) On entry, the diagonal elements of the tridiagonal matrix. On exit, the eigenvalues in ascending order.E E is DOUBLE PRECISION array, dimension (N1) On entry, the offdiagonal elements of the tridiagonal matrix. On exit, E has been destroyed.Q Q is COMPLEX*16 array, dimension (LDQ,N) On entry, Q must contain an QSIZ x N matrix whose columns unitarily orthonormal. It is a part of the unitary matrix that reduces the full dense Hermitian matrix to a (reducible) symmetric tridiagonal matrix.LDQ LDQ is INTEGER The leading dimension of the array Q. LDQ >= max(1,N).IWORK IWORK is INTEGER array, the dimension of IWORK must be at least 6 + 6*N + 5*N*lg N ( lg( N ) = smallest integer k such that 2^k >= N )RWORK RWORK is DOUBLE PRECISION array, dimension (1 + 3*N + 2*N*lg N + 3*N**2) ( lg( N ) = smallest integer k such that 2^k >= N )QSTORE QSTORE is COMPLEX*16 array, dimension (LDQS, N) Used to store parts of the eigenvector matrix when the updating matrix multiplies take place.LDQS LDQS is INTEGER The leading dimension of the array QSTORE. LDQS >= max(1,N).INFO INFO is INTEGER = 0: successful exit. < 0: if INFO = i, the ith argument had an illegal value. > 0: The algorithm failed to compute an eigenvalue while working on the submatrix lying in rows and columns INFO/(N+1) through mod(INFO,N+1). Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Date:
September 2012
Definition at line 145 of file zlaed0.f.
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