drotm.f3
Usage
Functions/Subroutines
subroutine drotm (n, dx, incx, dy, incy, dparam)
DROTM
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
N
!> N is INTEGER !> number of elements in input vector(s) !>
DX
!> DX is DOUBLE PRECISION array, dimension ( 1 + ( N - 1 )*abs( INCX ) ) !>
INCX
!> INCX is INTEGER !> storage spacing between elements of DX !>
DY
!> DY is DOUBLE PRECISION array, dimension ( 1 + ( N - 1 )*abs( INCY ) ) !>
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.
Definition at line 95 of file drotm.f.
Releases
2 releases since Debian 9 (Stretch); the text changed 1 time.