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| 1 | 1 | equemene | SUBROUTINE DROTM(N,DX,INCX,DY,INCY,DPARAM) |
|---|---|---|---|
| 2 | 1 | equemene | * .. Scalar Arguments .. |
| 3 | 1 | equemene | INTEGER INCX,INCY,N |
| 4 | 1 | equemene | * .. |
| 5 | 1 | equemene | * .. Array Arguments .. |
| 6 | 1 | equemene | DOUBLE PRECISION DPARAM(5),DX(1),DY(1) |
| 7 | 1 | equemene | * .. |
| 8 | 1 | equemene | * |
| 9 | 1 | equemene | * Purpose |
| 10 | 1 | equemene | * ======= |
| 11 | 1 | equemene | * |
| 12 | 1 | equemene | * APPLY THE MODIFIED GIVENS TRANSFORMATION, H, TO THE 2 BY N MATRIX |
| 13 | 1 | equemene | * |
| 14 | 1 | equemene | * (DX**T) , WHERE **T INDICATES TRANSPOSE. THE ELEMENTS OF DX ARE IN |
| 15 | 1 | equemene | * (DY**T) |
| 16 | 1 | equemene | * |
| 17 | 1 | equemene | * DX(LX+I*INCX), I = 0 TO N-1, WHERE LX = 1 IF INCX .GE. 0, ELSE |
| 18 | 1 | equemene | * LX = (-INCX)*N, AND SIMILARLY FOR SY USING LY AND INCY. |
| 19 | 1 | equemene | * WITH DPARAM(1)=DFLAG, H HAS ONE OF THE FOLLOWING FORMS.. |
| 20 | 1 | equemene | * |
| 21 | 1 | equemene | * DFLAG=-1.D0 DFLAG=0.D0 DFLAG=1.D0 DFLAG=-2.D0 |
| 22 | 1 | equemene | * |
| 23 | 1 | equemene | * (DH11 DH12) (1.D0 DH12) (DH11 1.D0) (1.D0 0.D0) |
| 24 | 1 | equemene | * H=( ) ( ) ( ) ( ) |
| 25 | 1 | equemene | * (DH21 DH22), (DH21 1.D0), (-1.D0 DH22), (0.D0 1.D0). |
| 26 | 1 | equemene | * SEE DROTMG FOR A DESCRIPTION OF DATA STORAGE IN DPARAM. |
| 27 | 1 | equemene | * |
| 28 | 1 | equemene | * Arguments |
| 29 | 1 | equemene | * ========= |
| 30 | 1 | equemene | * |
| 31 | 1 | equemene | * N (input) INTEGER |
| 32 | 1 | equemene | * number of elements in input vector(s) |
| 33 | 1 | equemene | * |
| 34 | 1 | equemene | * DX (input/output) DOUBLE PRECISION array, dimension N |
| 35 | 1 | equemene | * double precision vector with 5 elements |
| 36 | 1 | equemene | * |
| 37 | 1 | equemene | * INCX (input) INTEGER |
| 38 | 1 | equemene | * storage spacing between elements of DX |
| 39 | 1 | equemene | * |
| 40 | 1 | equemene | * DY (input/output) DOUBLE PRECISION array, dimension N |
| 41 | 1 | equemene | * double precision vector with N elements |
| 42 | 1 | equemene | * |
| 43 | 1 | equemene | * INCY (input) INTEGER |
| 44 | 1 | equemene | * storage spacing between elements of DY |
| 45 | 1 | equemene | * |
| 46 | 1 | equemene | * DPARAM (input/output) DOUBLE PRECISION array, dimension 5 |
| 47 | 1 | equemene | * DPARAM(1)=DFLAG |
| 48 | 1 | equemene | * DPARAM(2)=DH11 |
| 49 | 1 | equemene | * DPARAM(3)=DH21 |
| 50 | 1 | equemene | * DPARAM(4)=DH12 |
| 51 | 1 | equemene | * DPARAM(5)=DH22 |
| 52 | 1 | equemene | * |
| 53 | 1 | equemene | * ===================================================================== |
| 54 | 1 | equemene | * |
| 55 | 1 | equemene | * .. Local Scalars .. |
| 56 | 1 | equemene | DOUBLE PRECISION DFLAG,DH11,DH12,DH21,DH22,TWO,W,Z,ZERO |
| 57 | 1 | equemene | INTEGER I,KX,KY,NSTEPS |
| 58 | 1 | equemene | * .. |
| 59 | 1 | equemene | * .. Data statements .. |
| 60 | 1 | equemene | DATA ZERO,TWO/0.D0,2.D0/ |
| 61 | 1 | equemene | * .. |
| 62 | 1 | equemene | * |
| 63 | 1 | equemene | DFLAG = DPARAM(1) |
| 64 | 1 | equemene | IF (N.LE.0 .OR. (DFLAG+TWO.EQ.ZERO)) GO TO 140 |
| 65 | 1 | equemene | IF (.NOT. (INCX.EQ.INCY.AND.INCX.GT.0)) GO TO 70 |
| 66 | 1 | equemene | * |
| 67 | 1 | equemene | NSTEPS = N*INCX |
| 68 | 1 | equemene | IF (DFLAG) 50,10,30 |
| 69 | 1 | equemene | 10 CONTINUE |
| 70 | 1 | equemene | DH12 = DPARAM(4) |
| 71 | 1 | equemene | DH21 = DPARAM(3) |
| 72 | 1 | equemene | DO 20 I = 1,NSTEPS,INCX |
| 73 | 1 | equemene | W = DX(I) |
| 74 | 1 | equemene | Z = DY(I) |
| 75 | 1 | equemene | DX(I) = W + Z*DH12 |
| 76 | 1 | equemene | DY(I) = W*DH21 + Z |
| 77 | 1 | equemene | 20 CONTINUE |
| 78 | 1 | equemene | GO TO 140 |
| 79 | 1 | equemene | 30 CONTINUE |
| 80 | 1 | equemene | DH11 = DPARAM(2) |
| 81 | 1 | equemene | DH22 = DPARAM(5) |
| 82 | 1 | equemene | DO 40 I = 1,NSTEPS,INCX |
| 83 | 1 | equemene | W = DX(I) |
| 84 | 1 | equemene | Z = DY(I) |
| 85 | 1 | equemene | DX(I) = W*DH11 + Z |
| 86 | 1 | equemene | DY(I) = -W + DH22*Z |
| 87 | 1 | equemene | 40 CONTINUE |
| 88 | 1 | equemene | GO TO 140 |
| 89 | 1 | equemene | 50 CONTINUE |
| 90 | 1 | equemene | DH11 = DPARAM(2) |
| 91 | 1 | equemene | DH12 = DPARAM(4) |
| 92 | 1 | equemene | DH21 = DPARAM(3) |
| 93 | 1 | equemene | DH22 = DPARAM(5) |
| 94 | 1 | equemene | DO 60 I = 1,NSTEPS,INCX |
| 95 | 1 | equemene | W = DX(I) |
| 96 | 1 | equemene | Z = DY(I) |
| 97 | 1 | equemene | DX(I) = W*DH11 + Z*DH12 |
| 98 | 1 | equemene | DY(I) = W*DH21 + Z*DH22 |
| 99 | 1 | equemene | 60 CONTINUE |
| 100 | 1 | equemene | GO TO 140 |
| 101 | 1 | equemene | 70 CONTINUE |
| 102 | 1 | equemene | KX = 1 |
| 103 | 1 | equemene | KY = 1 |
| 104 | 1 | equemene | IF (INCX.LT.0) KX = 1 + (1-N)*INCX |
| 105 | 1 | equemene | IF (INCY.LT.0) KY = 1 + (1-N)*INCY |
| 106 | 1 | equemene | * |
| 107 | 1 | equemene | IF (DFLAG) 120,80,100 |
| 108 | 1 | equemene | 80 CONTINUE |
| 109 | 1 | equemene | DH12 = DPARAM(4) |
| 110 | 1 | equemene | DH21 = DPARAM(3) |
| 111 | 1 | equemene | DO 90 I = 1,N |
| 112 | 1 | equemene | W = DX(KX) |
| 113 | 1 | equemene | Z = DY(KY) |
| 114 | 1 | equemene | DX(KX) = W + Z*DH12 |
| 115 | 1 | equemene | DY(KY) = W*DH21 + Z |
| 116 | 1 | equemene | KX = KX + INCX |
| 117 | 1 | equemene | KY = KY + INCY |
| 118 | 1 | equemene | 90 CONTINUE |
| 119 | 1 | equemene | GO TO 140 |
| 120 | 1 | equemene | 100 CONTINUE |
| 121 | 1 | equemene | DH11 = DPARAM(2) |
| 122 | 1 | equemene | DH22 = DPARAM(5) |
| 123 | 1 | equemene | DO 110 I = 1,N |
| 124 | 1 | equemene | W = DX(KX) |
| 125 | 1 | equemene | Z = DY(KY) |
| 126 | 1 | equemene | DX(KX) = W*DH11 + Z |
| 127 | 1 | equemene | DY(KY) = -W + DH22*Z |
| 128 | 1 | equemene | KX = KX + INCX |
| 129 | 1 | equemene | KY = KY + INCY |
| 130 | 1 | equemene | 110 CONTINUE |
| 131 | 1 | equemene | GO TO 140 |
| 132 | 1 | equemene | 120 CONTINUE |
| 133 | 1 | equemene | DH11 = DPARAM(2) |
| 134 | 1 | equemene | DH12 = DPARAM(4) |
| 135 | 1 | equemene | DH21 = DPARAM(3) |
| 136 | 1 | equemene | DH22 = DPARAM(5) |
| 137 | 1 | equemene | DO 130 I = 1,N |
| 138 | 1 | equemene | W = DX(KX) |
| 139 | 1 | equemene | Z = DY(KY) |
| 140 | 1 | equemene | DX(KX) = W*DH11 + Z*DH12 |
| 141 | 1 | equemene | DY(KY) = W*DH21 + Z*DH22 |
| 142 | 1 | equemene | KX = KX + INCX |
| 143 | 1 | equemene | KY = KY + INCY |
| 144 | 1 | equemene | 130 CONTINUE |
| 145 | 1 | equemene | 140 CONTINUE |
| 146 | 1 | equemene | RETURN |
| 147 | 1 | equemene | END |