1CTPTRS(1)                LAPACK routine (version 3.2)                CTPTRS(1)
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NAME

6       CTPTRS - solves a triangular system of the form   A * X = B, A**T * X =
7       B, or 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 where A is  a  triangular
20       matrix  of  order  N  stored  in  packed  format, and B is an N-by-NRHS
21       matrix.  A check is made to verify that A is nonsingular.
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ARGUMENTS

24       UPLO    (input) CHARACTER*1
25               = 'U':  A is upper triangular;
26               = 'L':  A is lower triangular.
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28       TRANS   (input) CHARACTER*1
29               Specifies the form of the system of equations:
30               = 'N':  A * X = B     (No transpose)
31               = 'T':  A**T * X = B  (Transpose)
32               = 'C':  A**H * X = B  (Conjugate transpose)
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34       DIAG    (input) CHARACTER*1
35               = 'N':  A is non-unit triangular;
36               = 'U':  A is unit triangular.
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38       N       (input) INTEGER
39               The order of the matrix A.  N >= 0.
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41       NRHS    (input) INTEGER
42               The number of right hand sides, i.e., the number of columns  of
43               the matrix B.  NRHS >= 0.
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45       AP      (input) COMPLEX array, dimension (N*(N+1)/2)
46               The  upper or lower triangular matrix A, packed columnwise in a
47               linear array.  The j-th column of A is stored in the  array  AP
48               as  follows:  if  UPLO  =  'U',  AP(i + (j-1)*j/2) = A(i,j) for
49               1<=i<=j; if UPLO = 'L', AP(i + (j-1)*(2*n-j)/2)  =  A(i,j)  for
50               j<=i<=n.
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52       B       (input/output) COMPLEX array, dimension (LDB,NRHS)
53               On  entry, the right hand side matrix B.  On exit, if INFO = 0,
54               the solution matrix X.
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56       LDB     (input) INTEGER
57               The leading dimension of the array B.  LDB >= max(1,N).
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59       INFO    (output) INTEGER
60               = 0:  successful exit
61               < 0:  if INFO = -i, the i-th argument had an illegal value
62               > 0:  if INFO = i, the i-th diagonal  element  of  A  is  zero,
63               indicating that the matrix is singular and the solutions X have
64               not been computed.
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68 LAPACK routine (version 3.2)    November 2008                       CTPTRS(1)
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