1DTRMV(1)                         BLAS routine                         DTRMV(1)
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NAME

6       DTRMV  -  performs one of the matrix-vector operations   x := A*x, or x
7       := A'*x,
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SYNOPSIS

10       SUBROUTINE DTRMV(UPLO,TRANS,DIAG,N,A,LDA,X,INCX)
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12           INTEGER                                      INCX,LDA,N
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14           CHARACTER                                    DIAG,TRANS,UPLO
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16           DOUBLE                                       PRECISION
17                                                        A(LDA,*),X(*)
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PURPOSE

20       DTRMV  performs one of the matrix-vector operations
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22       where  x  is an n element vector and  A is an n by n unit, or non-unit,
23       upper or lower triangular matrix.
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ARGUMENTS

27       UPLO   - CHARACTER*1.
28              On entry, UPLO specifies whether the matrix is an upper or lower
29              triangular matrix as follows:
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31              UPLO = 'U' or 'u'   A is an upper triangular matrix.
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33              UPLO = 'L' or 'l'   A is a lower triangular matrix.
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35              Unchanged on exit.
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37       TRANS  - CHARACTER*1.
38              On  entry, TRANS specifies the operation to be performed as fol‐
39              lows:
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41              TRANS = 'N' or 'n'   x := A*x.
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43              TRANS = 'T' or 't'   x := A'*x.
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45              TRANS = 'C' or 'c'   x := A'*x.
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47              Unchanged on exit.
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49       DIAG   - CHARACTER*1.
50              On entry, DIAG specifies whether or not A is unit triangular  as
51              follows:
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53              DIAG = 'U' or 'u'   A is assumed to be unit triangular.
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55              DIAG = 'N' or 'n'   A is not assumed to be unit triangular.
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57              Unchanged on exit.
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59       N      - INTEGER.
60              On  entry,  N specifies the order of the matrix A.  N must be at
61              least zero.  Unchanged on exit.
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63       A      - DOUBLE PRECISION array of DIMENSION ( LDA, n ).
64              Before entry with  UPLO = 'U' or 'u', the leading n by  n  upper
65              triangular part of the array A must contain the upper triangular
66              matrix and the strictly lower triangular part of A is not refer‐
67              enced.   Before entry with UPLO = 'L' or 'l', the leading n by n
68              lower triangular part of the array A must contain the lower tri‐
69              angular  matrix  and  the strictly upper triangular part of A is
70              not referenced.  Note that when  DIAG = 'U' or 'u', the diagonal
71              elements  of  A are not referenced either, but are assumed to be
72              unity.  Unchanged on exit.
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74       LDA    - INTEGER.
75              On entry, LDA specifies the first dimension of A as declared  in
76              the  calling  (sub)  program.  LDA must be at least max( 1, n ).
77              Unchanged on exit.
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79       X      - DOUBLE PRECISION array of dimension at least
80              ( 1 + ( n - 1 )*abs( INCX ) ).  Before  entry,  the  incremented
81              array X must contain the n element vector x. On exit, X is over‐
82              written with the tranformed vector x.
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84       INCX   - INTEGER.
85              On entry, INCX specifies the increment for the  elements  of  X.
86              INCX must not be zero.  Unchanged on exit.
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FURTHER DETAILS

89       Level 2 Blas routine.
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91       -- Written on 22-October-1986.
92          Jack Dongarra, Argonne National Lab.
93          Jeremy Du Croz, Nag Central Office.
94          Sven Hammarling, Nag Central Office.
95          Richard Hanson, Sandia National Labs.
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100BLAS routine                     November 2008                        DTRMV(1)