rotm(3) | LAPACK | rotm(3) |
rotm - rotm: apply modified (fast) plane rotation
subroutine drotm (n, dx, incx, dy, incy, dparam)
DROTM subroutine srotm (n, sx, incx, sy, incy, sparam)
SROTM
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 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 California Berkeley
Univ. of Colorado Denver
NAG Ltd.
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 is INTEGER number of elements in input vector(s)
SX
SX is REAL array, dimension ( 1 + ( N - 1 )*abs( INCX ) )
INCX
INCX is INTEGER storage spacing between elements of SX
SY
SY is REAL array, dimension ( 1 + ( N - 1 )*abs( INCY ) )
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 California Berkeley
Univ. of Colorado Denver
NAG Ltd.
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Fri Aug 9 2024 02:33:22 | Version 3.12.0 |