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

6       CTPTRS  - a triangular system of the form   A * X = B, A**T * X = B, or
7       A**H * X = B,
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SYNOPSIS

10       SUBROUTINE CTPTRS( UPLO, TRANS, DIAG, N, NRHS, AP, B, LDB, INFO )
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12           CHARACTER      DIAG, TRANS, UPLO
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14           INTEGER        INFO, LDB, N, NRHS
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16           COMPLEX        AP( * ), B( LDB, * )
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PURPOSE

19       CTPTRS solves a triangular system of the form
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21       where A is a triangular matrix of order N stored in packed format,  and
22       B  is an N-by-NRHS matrix.  A check is made to verify that A is nonsin‐
23       gular.
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ARGUMENTS

27       UPLO    (input) CHARACTER*1
28               = 'U':  A is upper triangular;
29               = 'L':  A is lower triangular.
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31       TRANS   (input) CHARACTER*1
32               Specifies the form of the system of equations:
33               = 'N':  A * X = B     (No transpose)
34               = 'T':  A**T * X = B  (Transpose)
35               = 'C':  A**H * X = B  (Conjugate transpose)
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37       DIAG    (input) CHARACTER*1
38               = 'N':  A is non-unit triangular;
39               = 'U':  A is unit triangular.
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41       N       (input) INTEGER
42               The order of the matrix A.  N >= 0.
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44       NRHS    (input) INTEGER
45               The number of right hand sides, i.e., the number of columns  of
46               the matrix B.  NRHS >= 0.
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48       AP      (input) COMPLEX array, dimension (N*(N+1)/2)
49               The  upper or lower triangular matrix A, packed columnwise in a
50               linear array.  The j-th column of A is stored in the  array  AP
51               as  follows:  if  UPLO  =  'U',  AP(i + (j-1)*j/2) = A(i,j) for
52               1<=i<=j; if UPLO = 'L', AP(i + (j-1)*(2*n-j)/2)  =  A(i,j)  for
53               j<=i<=n.
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55       B       (input/output) COMPLEX array, dimension (LDB,NRHS)
56               On  entry, the right hand side matrix B.  On exit, if INFO = 0,
57               the solution matrix X.
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59       LDB     (input) INTEGER
60               The leading dimension of the array B.  LDB >= max(1,N).
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62       INFO    (output) INTEGER
63               = 0:  successful exit
64               < 0:  if INFO = -i, the i-th argument had an illegal value
65               > 0:  if INFO = i, the i-th diagonal  element  of  A  is  zero,
66               indicating that the matrix is singular and the solutions X have
67               not been computed.
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71 LAPACK routine (version 3.1)    November 2006                       CTPTRS(1)
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