drotm.f(3)

NAME
drotm.f -

SYNOPSIS

  Functions/Subroutines
subroutine drotm (N, DX, INCX, DY, INCY, DPARAM)
DROTM

Function/Subroutine Documentation

  subroutine drotm (integerN, double precision, dimension(*)DX, integerINCX, double precision, dimension(*)DY, integerINCY, double precision, dimension(5)DPARAM)

DROTM Purpose:

        APPLY THE MODIFIED GIVENS TRANSFORMATION, H, TO THE 2 BY N MATRIX
        (DX**T) , WHERE **T INDICATES TRANSPOSE. THE ELEMENTS OF DX ARE IN
        (DY**T)
        DX(LX+I*INCX), I = 0 TO N-1, WHERE LX = 1 IF INCX .GE. 0, ELSE
        LX = (-INCX)*N, AND SIMILARLY FOR SY USING LY AND INCY.
        WITH DPARAM(1)=DFLAG, H HAS ONE OF THE FOLLOWING FORMS..
        DFLAG=-1.D0     DFLAG=0.D0        DFLAG=1.D0     DFLAG=-2.D0
          (DH11  DH12)    (1.D0  DH12)    (DH11  1.D0)    (1.D0  0.D0)
        H=(          )    (          )    (          )    (          )
          (DH21  DH22),   (DH21  1.D0),   (-1.D0 DH22),   (0.D0  1.D0).
        SEE DROTMG FOR A DESCRIPTION OF DATA STORAGE IN DPARAM.

Parameters:
    N

              N is INTEGER
             number of elements in input vector(s)

    DX

              DX is DOUBLE PRECISION array, dimension N
             double precision vector with N elements

    INCX

              INCX is INTEGER
             storage spacing between elements of DX

    DY

              DY is DOUBLE PRECISION array, dimension N
             double precision vector with N elements

    INCY

              INCY is INTEGER
             storage spacing between elements of DY

    DPARAM

              DPARAM is DOUBLE PRECISION array, dimension 5
         DPARAM(1)=DFLAG
         DPARAM(2)=DH11
         DPARAM(3)=DH21
         DPARAM(4)=DH12
         DPARAM(5)=DH22

Author:
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Date:
    November 2011

Definition at line 99 of file drotm.f.

Author

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