1CPTSV(1)                 LAPACK routine (version 3.1)                 CPTSV(1)
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NAME

6       CPTSV  -  the solution to a complex system of linear equations A*X = B,
7       where A is an N-by-N Hermitian positive  definite  tridiagonal  matrix,
8       and X and B are N-by-NRHS matrices
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SYNOPSIS

11       SUBROUTINE CPTSV( N, NRHS, D, E, B, LDB, INFO )
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13           INTEGER       INFO, LDB, N, NRHS
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15           REAL          D( * )
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17           COMPLEX       B( LDB, * ), E( * )
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PURPOSE

20       CPTSV computes the solution to a complex system of linear equations A*X
21       = B, where A is  an  N-by-N  Hermitian  positive  definite  tridiagonal
22       matrix, and X and B are N-by-NRHS matrices.
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24       A  is factored as A = L*D*L**H, and the factored form of A is then used
25       to solve the system of equations.
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ARGUMENTS

29       N       (input) INTEGER
30               The order of the matrix A.  N >= 0.
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32       NRHS    (input) INTEGER
33               The number of right hand sides, i.e., the number of columns  of
34               the matrix B.  NRHS >= 0.
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36       D       (input/output) REAL array, dimension (N)
37               On  entry, the n diagonal elements of the tridiagonal matrix A.
38               On exit, the n diagonal elements of the diagonal matrix D  from
39               the factorization A = L*D*L**H.
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41       E       (input/output) COMPLEX array, dimension (N-1)
42               On  entry,  the  (n-1)  subdiagonal elements of the tridiagonal
43               matrix A.  On exit, the (n-1) subdiagonal elements of the  unit
44               bidiagonal  factor  L  from the L*D*L**H factorization of A.  E
45               can also be regarded as the superdiagonal of the unit  bidiago‐
46               nal factor U from the U**H*D*U factorization of A.
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48       B       (input/output) COMPLEX array, dimension (LDB,NRHS)
49               On  entry, the N-by-NRHS right hand side matrix B.  On exit, if
50               INFO = 0, the N-by-NRHS solution matrix X.
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52       LDB     (input) INTEGER
53               The leading dimension of the array B.  LDB >= max(1,N).
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55       INFO    (output) INTEGER
56               = 0:  successful exit
57               < 0:  if INFO = -i, the i-th argument had an illegal value
58               > 0:  if INFO = i, the leading minor of order i is not positive
59               definite,  and the solution has not been computed.  The factor‐
60               ization has not been completed unless i = N.
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64 LAPACK routine (version 3.1)    November 2006                        CPTSV(1)