srotm.f

NAME

srotm.f −

SYNOPSIS

Functions/Subroutines

subroutine srotm (N, SX, INCX, SY, INCY, SPARAM)
SROTM

Function/Subroutine Documentation

subroutine srotm (integerN, real, dimension(*)SX, integerINCX, real, dimension(*)SY, integerINCY, real, dimension(5)SPARAM)
SROTM Purpose:

APPLY THE MODIFIED GIVENS TRANSFORMATION, H, TO THE 2 BY N MATRIX

(SX**T) , WHERE **T INDICATES TRANSPOSE. THE ELEMENTS OF SX ARE IN
(SX**T)

SX(LX+I*INCX), I = 0 TO N-1, WHERE LX = 1 IF INCX .GE. 0, ELSE
LX = (-INCX)*N, AND SIMILARLY FOR SY USING USING LY AND INCY.
WITH SPARAM(1)=SFLAG, H HAS ONE OF THE FOLLOWING FORMS..

SFLAG=-1.E0 SFLAG=0.E0 SFLAG=1.E0 SFLAG=-2.E0

(SH11 SH12) (1.E0 SH12) (SH11 1.E0) (1.E0 0.E0)
H=( ) ( ) ( ) ( )
(SH21 SH22), (SH21 1.E0), (-1.E0 SH22), (0.E0 1.E0).
SEE SROTMG FOR A DESCRIPTION OF DATA STORAGE IN SPARAM.

Parameters:

N

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

SX

SX is REAL array, dimension N
double precision vector with N elements

INCX

INCX is INTEGER
storage spacing between elements of SX

SY

SY is REAL array, dimension N
double precision vector with N elements

INCY

INCY is INTEGER
storage spacing between elements of SY

SPARAM

SPARAM is REAL array, dimension 5
SPARAM(1)=SFLAG
SPARAM(2)=SH11
SPARAM(3)=SH21
SPARAM(4)=SH12
SPARAM(5)=SH22

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

November 2011

Definition at line 100 of file srotm.f.

Author

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