LAPACK  3.5.0
LAPACK: Linear Algebra PACKage
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drotm.f File Reference

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Functions/Subroutines

subroutine drotm (N, DX, INCX, DY, INCY, DPARAM)
 DROTM More...
 

Function/Subroutine Documentation

subroutine drotm ( integer  N,
double precision, dimension(*)  DX,
integer  INCX,
double precision, dimension(*)  DY,
integer  INCY,
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
[in]N
          N is INTEGER
         number of elements in input vector(s)
[in,out]DX
          DX is DOUBLE PRECISION array, dimension N
         double precision vector with N elements
[in]INCX
          INCX is INTEGER
         storage spacing between elements of DX
[in,out]DY
          DY is DOUBLE PRECISION array, dimension N
         double precision vector with N elements
[in]INCY
          INCY is INTEGER
         storage spacing between elements of DY
[in,out]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.

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