1CGTTS2(1)           LAPACK auxiliary routine (version 3.1)           CGTTS2(1)
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NAME

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

10       SUBROUTINE CGTTS2( ITRANS, N, NRHS, DL, D, DU, DU2, IPIV, B, LDB )
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12           INTEGER        ITRANS, LDB, N, NRHS
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14           INTEGER        IPIV( * )
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16           COMPLEX        B( LDB, * ), D( * ), DL( * ), DU( * ), DU2( * )
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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.
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ARGUMENTS

25       ITRANS  (input) INTEGER
26               Specifies the form of the system of equations.  = 0:  A * X = B
27               (No transpose)
28               = 1:  A**T * X = B  (Transpose)
29               = 2:  A**H * X = B  (Conjugate transpose)
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31       N       (input) INTEGER
32               The order of the matrix A.
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34       NRHS    (input) INTEGER
35               The number of right hand sides, i.e., the number of columns  of
36               the matrix B.  NRHS >= 0.
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38       DL      (input) COMPLEX array, dimension (N-1)
39               The (n-1) multipliers that define the matrix L from the LU fac‐
40               torization of A.
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42       D       (input) COMPLEX array, dimension (N)
43               The n diagonal elements of the upper triangular matrix  U  from
44               the LU factorization of A.
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46       DU      (input) COMPLEX array, dimension (N-1)
47               The (n-1) elements of the first super-diagonal of U.
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49       DU2     (input) COMPLEX array, dimension (N-2)
50               The (n-2) elements of the second super-diagonal of U.
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52       IPIV    (input) INTEGER array, dimension (N)
53               The  pivot  indices;  for  1 <= i <= n, row i of the matrix was
54               interchanged with row IPIV(i).  IPIV(i) will always be either i
55               or  i+1;  IPIV(i)  =  i  indicates  a  row  interchange was not
56               required.
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58       B       (input/output) COMPLEX array, dimension (LDB,NRHS)
59               On entry, the matrix of right hand side vectors B.  On exit,  B
60               is overwritten by the solution vectors X.
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62       LDB     (input) INTEGER
63               The leading dimension of the array B.  LDB >= max(1,N).
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67 LAPACK auxiliary routine (versionNo3v.e1m)ber 2006                       CGTTS2(1)
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