1CGTTS2(1)           LAPACK auxiliary routine (version 3.2)           CGTTS2(1)
2
3
4

NAME

6       CGTTS2  - solves one of the systems of equations  A * X = B, A**T * X =
7       B, or A**H * X = B,
8

SYNOPSIS

10       SUBROUTINE CGTTS2( ITRANS, N, NRHS, DL, D, DU, DU2, IPIV, B, LDB )
11
12           INTEGER        ITRANS, LDB, N, NRHS
13
14           INTEGER        IPIV( * )
15
16           COMPLEX        B( LDB, * ), D( * ), DL( * ), DU( * ), DU2( * )
17

PURPOSE

19       CGTTS2 solves one of the systems of equations
20          A * X = B,  A**T * X = B,  or  A**H * X  =  B,  with  a  tridiagonal
21       matrix A using the LU factorization computed by CGTTRF.
22

ARGUMENTS

24       ITRANS  (input) INTEGER
25               Specifies the form of the system of equations.  = 0:  A * X = B
26               (No transpose)
27               = 1:  A**T * X = B  (Transpose)
28               = 2:  A**H * X = B  (Conjugate transpose)
29
30       N       (input) INTEGER
31               The order of the matrix A.
32
33       NRHS    (input) INTEGER
34               The number of right hand sides, i.e., the number of columns  of
35               the matrix B.  NRHS >= 0.
36
37       DL      (input) COMPLEX array, dimension (N-1)
38               The (n-1) multipliers that define the matrix L from the LU fac‐
39               torization of A.
40
41       D       (input) COMPLEX array, dimension (N)
42               The n diagonal elements of the upper triangular matrix  U  from
43               the LU factorization of A.
44
45       DU      (input) COMPLEX array, dimension (N-1)
46               The (n-1) elements of the first super-diagonal of U.
47
48       DU2     (input) COMPLEX array, dimension (N-2)
49               The (n-2) elements of the second super-diagonal of U.
50
51       IPIV    (input) INTEGER array, dimension (N)
52               The  pivot  indices;  for  1 <= i <= n, row i of the matrix was
53               interchanged with row IPIV(i).  IPIV(i) will always be either i
54               or  i+1;  IPIV(i)  =  i  indicates  a  row  interchange was not
55               required.
56
57       B       (input/output) COMPLEX array, dimension (LDB,NRHS)
58               On entry, the matrix of right hand side vectors B.  On exit,  B
59               is overwritten by the solution vectors X.
60
61       LDB     (input) INTEGER
62               The leading dimension of the array B.  LDB >= max(1,N).
63
64
65
66 LAPACK auxiliary routine (versionNo3v.e2m)ber 2008                       CGTTS2(1)
Impressum