1DGTTS2(1)           LAPACK auxiliary routine (version 3.2)           DGTTS2(1)
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NAME

6       DGTTS2 - solves one of the systems of equations  A*X = B or A'*X = B,
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SYNOPSIS

9       SUBROUTINE DGTTS2( ITRANS, N, NRHS, DL, D, DU, DU2, IPIV, B, LDB )
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11           INTEGER        ITRANS, LDB, N, NRHS
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13           INTEGER        IPIV( * )
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15           DOUBLE         PRECISION  B(  LDB,  *  ), D( * ), DL( * ), DU( * ),
16                          DU2( * )
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PURPOSE

19       DGTTS2 solves one of the systems of equations
20          A*X = B  or  A'*X = B, with a tridiagonal matrix A using the LU fac‐
21       torization computed by DGTTRF.
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ARGUMENTS

24       ITRANS  (input) INTEGER
25               Specifies the form of the system of equations.  = 0:  A * X = B
26               (No transpose)
27               = 1:  A'* X = B  (Transpose)
28               = 2:  A'* X = B  (Conjugate transpose = Transpose)
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30       N       (input) INTEGER
31               The order of the matrix A.
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33       NRHS    (input) INTEGER
34               The number of right hand sides, i.e., the number of columns  of
35               the matrix B.  NRHS >= 0.
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37       DL      (input) DOUBLE PRECISION array, dimension (N-1)
38               The (n-1) multipliers that define the matrix L from the LU fac‐
39               torization of A.
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41       D       (input) DOUBLE PRECISION array, dimension (N)
42               The n diagonal elements of the upper triangular matrix  U  from
43               the LU factorization of A.
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45       DU      (input) DOUBLE PRECISION array, dimension (N-1)
46               The (n-1) elements of the first super-diagonal of U.
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48       DU2     (input) DOUBLE PRECISION array, dimension (N-2)
49               The (n-2) elements of the second super-diagonal of U.
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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.
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57       B       (input/output) DOUBLE PRECISION 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.
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61       LDB     (input) INTEGER
62               The leading dimension of the array B.  LDB >= max(1,N).
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66 LAPACK auxiliary routine (versionNo3v.e2m)ber 2008                       DGTTS2(1)
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