DLAEDA (3)  Linux Manuals
NAME
dlaeda.f 
SYNOPSIS
Functions/Subroutines
subroutine dlaeda (N, TLVLS, CURLVL, CURPBM, PRMPTR, PERM, GIVPTR, GIVCOL, GIVNUM, Q, QPTR, Z, ZTEMP, INFO)
DLAEDA used by sstedc. Computes the Z vector determining the rankone modification of the diagonal matrix. Used when the original matrix is dense.
Function/Subroutine Documentation
subroutine dlaeda (integerN, integerTLVLS, integerCURLVL, integerCURPBM, integer, dimension( * )PRMPTR, integer, dimension( * )PERM, integer, dimension( * )GIVPTR, integer, dimension( 2, * )GIVCOL, double precision, dimension( 2, * )GIVNUM, double precision, dimension( * )Q, integer, dimension( * )QPTR, double precision, dimension( * )Z, double precision, dimension( * )ZTEMP, integerINFO)
DLAEDA used by sstedc. Computes the Z vector determining the rankone modification of the diagonal matrix. Used when the original matrix is dense.
Purpose:

DLAEDA computes the Z vector corresponding to the merge step in the CURLVLth step of the merge process with TLVLS steps for the CURPBMth problem.
Parameters:

N
N is INTEGER The dimension of the symmetric tridiagonal matrix. N >= 0.
TLVLSTLVLS is INTEGER The total number of merging levels in the overall divide and conquer tree.
CURLVLCURLVL is INTEGER The current level in the overall merge routine, 0 <= curlvl <= tlvls.
CURPBMCURPBM is INTEGER The current problem in the current level in the overall merge routine (counting from upper left to lower right).
PRMPTRPRMPTR is INTEGER array, dimension (N lg N) Contains a list of pointers which indicate where in PERM a level's permutation is stored. PRMPTR(i+1)  PRMPTR(i) indicates the size of the permutation and incidentally the size of the full, nondeflated problem.
PERMPERM is INTEGER array, dimension (N lg N) Contains the permutations (from deflation and sorting) to be applied to each eigenblock.
GIVPTRGIVPTR is INTEGER array, dimension (N lg N) Contains a list of pointers which indicate where in GIVCOL a level's Givens rotations are stored. GIVPTR(i+1)  GIVPTR(i) indicates the number of Givens rotations.
GIVCOLGIVCOL is INTEGER array, dimension (2, N lg N) Each pair of numbers indicates a pair of columns to take place in a Givens rotation.
GIVNUMGIVNUM is DOUBLE PRECISION array, dimension (2, N lg N) Each number indicates the S value to be used in the corresponding Givens rotation.
QQ is DOUBLE PRECISION array, dimension (N**2) Contains the square eigenblocks from previous levels, the starting positions for blocks are given by QPTR.
QPTRQPTR is INTEGER array, dimension (N+2) Contains a list of pointers which indicate where in Q an eigenblock is stored. SQRT( QPTR(i+1)  QPTR(i) ) indicates the size of the block.
ZZ is DOUBLE PRECISION array, dimension (N) On output this vector contains the updating vector (the last row of the first subeigenvector matrix and the first row of the second subeigenvector matrix).
ZTEMPZTEMP is DOUBLE PRECISION array, dimension (N)
INFOINFO is INTEGER = 0: successful exit. < 0: if INFO = i, the ith argument had an illegal value.
Author:

Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Date:
 September 2012
Contributors:
 Jeff Rutter, Computer Science Division, University of California at Berkeley, USA
Definition at line 166 of file dlaeda.f.
Author
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