zpttrf (l)  Linux Man Pages
zpttrf: computes the L*D*Laq factorization of a complex Hermitian positive definite tridiagonal matrix A
Command to display zpttrf
manual in Linux: $ man l zpttrf
NAME
ZPTTRF  computes the L*D*Laq factorization of a complex Hermitian positive definite tridiagonal matrix A
SYNOPSIS
 SUBROUTINE ZPTTRF(

N, D, E, INFO )

INTEGER
INFO, N

DOUBLE
PRECISION D( * )

COMPLEX*16
E( * )
PURPOSE
ZPTTRF computes the L*D*Laq factorization of a complex Hermitian
positive definite tridiagonal matrix A. The factorization may also
be regarded as having the form A = Uaq*D*U.
ARGUMENTS
 N (input) INTEGER

The order of the matrix A. N >= 0.
 D (input/output) DOUBLE PRECISION array, dimension (N)

On entry, the n diagonal elements of the tridiagonal matrix
A. On exit, the n diagonal elements of the diagonal matrix
D from the L*D*Laq factorization of A.
 E (input/output) COMPLEX*16 array, dimension (N1)

On entry, the (n1) subdiagonal elements of the tridiagonal
matrix A. On exit, the (n1) subdiagonal elements of the
unit bidiagonal factor L from the L*D*Laq factorization of A.
E can also be regarded as the superdiagonal of the unit
bidiagonal factor U from the Uaq*D*U factorization of A.
 INFO (output) INTEGER

= 0: successful exit
< 0: if INFO = k, the kth argument had an illegal value
> 0: if INFO = k, the leading minor of order k is not
positive definite; if k < N, the factorization could not
be completed, while if k = N, the factorization was
completed, but D(N) <= 0.
Pages related to zpttrf
 zpttrf (3)
 zpttrs (l)  solves a tridiagonal system of the form A * X = B using the factorization A = Uaq*D*U or A = L*D*Laq computed by ZPTTRF
 zptts2 (l)  solves a tridiagonal system of the form A * X = B using the factorization A = Uaq*D*U or A = L*D*Laq computed by ZPTTRF
 zptcon (l)  computes the reciprocal of the condition number (in the 1norm) of a complex Hermitian positive definite tridiagonal matrix using the factorization A = L*D*L**H or A = U**H*D*U computed by ZPTTRF
 zpteqr (l)  computes all eigenvalues and, optionally, eigenvectors of a symmetric positive definite tridiagonal matrix by first factoring the matrix using DPTTRF and then calling ZBDSQR to compute the singular values of the bidiagonal factor
 zptrfs (l)  improves the computed solution to a system of linear equations when the coefficient matrix is Hermitian positive definite and tridiagonal, and provides error bounds and backward error estimates for the solution
 zptsv (l)  computes the solution to a complex system of linear equations A*X = B, where A is an NbyN Hermitian positive definite tridiagonal matrix, and X and B are NbyNRHS matrices
 zptsvx (l)  uses the factorization A = L*D*L**H to compute the solution to a complex system of linear equations A*X = B, where A is an NbyN Hermitian positive definite tridiagonal matrix and X and B are NbyNRHS matrices