You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
148 lines
3.6 KiB
148 lines
3.6 KiB
SUBROUTINE SROTM(N,SX,INCX,SY,INCY,SPARAM)
|
|
* .. Scalar Arguments ..
|
|
INTEGER INCX,INCY,N
|
|
* ..
|
|
* .. Array Arguments ..
|
|
REAL SPARAM(5),SX(*),SY(*)
|
|
* ..
|
|
*
|
|
* 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
|
|
* (DX**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.
|
|
*
|
|
*
|
|
* Arguments
|
|
* =========
|
|
*
|
|
* N (input) INTEGER
|
|
* number of elements in input vector(s)
|
|
*
|
|
* SX (input/output) REAL array, dimension N
|
|
* double precision vector with N elements
|
|
*
|
|
* INCX (input) INTEGER
|
|
* storage spacing between elements of SX
|
|
*
|
|
* SY (input/output) REAL array, dimension N
|
|
* double precision vector with N elements
|
|
*
|
|
* INCY (input) INTEGER
|
|
* storage spacing between elements of SY
|
|
*
|
|
* SPARAM (input/output) REAL array, dimension 5
|
|
* SPARAM(1)=SFLAG
|
|
* SPARAM(2)=SH11
|
|
* SPARAM(3)=SH21
|
|
* SPARAM(4)=SH12
|
|
* SPARAM(5)=SH22
|
|
*
|
|
* =====================================================================
|
|
*
|
|
* .. Local Scalars ..
|
|
REAL SFLAG,SH11,SH12,SH21,SH22,TWO,W,Z,ZERO
|
|
INTEGER I,KX,KY,NSTEPS
|
|
* ..
|
|
* .. Data statements ..
|
|
DATA ZERO,TWO/0.E0,2.E0/
|
|
* ..
|
|
*
|
|
SFLAG = SPARAM(1)
|
|
IF (N.LE.0 .OR. (SFLAG+TWO.EQ.ZERO)) GO TO 140
|
|
IF (.NOT. (INCX.EQ.INCY.AND.INCX.GT.0)) GO TO 70
|
|
*
|
|
NSTEPS = N*INCX
|
|
IF (SFLAG) 50,10,30
|
|
10 CONTINUE
|
|
SH12 = SPARAM(4)
|
|
SH21 = SPARAM(3)
|
|
DO 20 I = 1,NSTEPS,INCX
|
|
W = SX(I)
|
|
Z = SY(I)
|
|
SX(I) = W + Z*SH12
|
|
SY(I) = W*SH21 + Z
|
|
20 CONTINUE
|
|
GO TO 140
|
|
30 CONTINUE
|
|
SH11 = SPARAM(2)
|
|
SH22 = SPARAM(5)
|
|
DO 40 I = 1,NSTEPS,INCX
|
|
W = SX(I)
|
|
Z = SY(I)
|
|
SX(I) = W*SH11 + Z
|
|
SY(I) = -W + SH22*Z
|
|
40 CONTINUE
|
|
GO TO 140
|
|
50 CONTINUE
|
|
SH11 = SPARAM(2)
|
|
SH12 = SPARAM(4)
|
|
SH21 = SPARAM(3)
|
|
SH22 = SPARAM(5)
|
|
DO 60 I = 1,NSTEPS,INCX
|
|
W = SX(I)
|
|
Z = SY(I)
|
|
SX(I) = W*SH11 + Z*SH12
|
|
SY(I) = W*SH21 + Z*SH22
|
|
60 CONTINUE
|
|
GO TO 140
|
|
70 CONTINUE
|
|
KX = 1
|
|
KY = 1
|
|
IF (INCX.LT.0) KX = 1 + (1-N)*INCX
|
|
IF (INCY.LT.0) KY = 1 + (1-N)*INCY
|
|
*
|
|
IF (SFLAG) 120,80,100
|
|
80 CONTINUE
|
|
SH12 = SPARAM(4)
|
|
SH21 = SPARAM(3)
|
|
DO 90 I = 1,N
|
|
W = SX(KX)
|
|
Z = SY(KY)
|
|
SX(KX) = W + Z*SH12
|
|
SY(KY) = W*SH21 + Z
|
|
KX = KX + INCX
|
|
KY = KY + INCY
|
|
90 CONTINUE
|
|
GO TO 140
|
|
100 CONTINUE
|
|
SH11 = SPARAM(2)
|
|
SH22 = SPARAM(5)
|
|
DO 110 I = 1,N
|
|
W = SX(KX)
|
|
Z = SY(KY)
|
|
SX(KX) = W*SH11 + Z
|
|
SY(KY) = -W + SH22*Z
|
|
KX = KX + INCX
|
|
KY = KY + INCY
|
|
110 CONTINUE
|
|
GO TO 140
|
|
120 CONTINUE
|
|
SH11 = SPARAM(2)
|
|
SH12 = SPARAM(4)
|
|
SH21 = SPARAM(3)
|
|
SH22 = SPARAM(5)
|
|
DO 130 I = 1,N
|
|
W = SX(KX)
|
|
Z = SY(KY)
|
|
SX(KX) = W*SH11 + Z*SH12
|
|
SY(KY) = W*SH21 + Z*SH22
|
|
KX = KX + INCX
|
|
KY = KY + INCY
|
|
130 CONTINUE
|
|
140 CONTINUE
|
|
RETURN
|
|
END
|