drotm.f (3) Linux Manual Page

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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