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| 1 | 1 | equemene | SUBROUTINE DGER(M,N,ALPHA,X,INCX,Y,INCY,A,LDA) |
|---|---|---|---|
| 2 | 1 | equemene | * .. Scalar Arguments .. |
| 3 | 1 | equemene | DOUBLE PRECISION ALPHA |
| 4 | 1 | equemene | INTEGER INCX,INCY,LDA,M,N |
| 5 | 1 | equemene | * .. |
| 6 | 1 | equemene | * .. Array Arguments .. |
| 7 | 1 | equemene | DOUBLE PRECISION A(LDA,*),X(*),Y(*) |
| 8 | 1 | equemene | * .. |
| 9 | 1 | equemene | * |
| 10 | 1 | equemene | * Purpose |
| 11 | 1 | equemene | * ======= |
| 12 | 1 | equemene | * |
| 13 | 1 | equemene | * DGER performs the rank 1 operation |
| 14 | 1 | equemene | * |
| 15 | 1 | equemene | * A := alpha*x*y' + A, |
| 16 | 1 | equemene | * |
| 17 | 1 | equemene | * where alpha is a scalar, x is an m element vector, y is an n element |
| 18 | 1 | equemene | * vector and A is an m by n matrix. |
| 19 | 1 | equemene | * |
| 20 | 1 | equemene | * Arguments |
| 21 | 1 | equemene | * ========== |
| 22 | 1 | equemene | * |
| 23 | 1 | equemene | * M - INTEGER. |
| 24 | 1 | equemene | * On entry, M specifies the number of rows of the matrix A. |
| 25 | 1 | equemene | * M must be at least zero. |
| 26 | 1 | equemene | * Unchanged on exit. |
| 27 | 1 | equemene | * |
| 28 | 1 | equemene | * N - INTEGER. |
| 29 | 1 | equemene | * On entry, N specifies the number of columns of the matrix A. |
| 30 | 1 | equemene | * N must be at least zero. |
| 31 | 1 | equemene | * Unchanged on exit. |
| 32 | 1 | equemene | * |
| 33 | 1 | equemene | * ALPHA - DOUBLE PRECISION. |
| 34 | 1 | equemene | * On entry, ALPHA specifies the scalar alpha. |
| 35 | 1 | equemene | * Unchanged on exit. |
| 36 | 1 | equemene | * |
| 37 | 1 | equemene | * X - DOUBLE PRECISION array of dimension at least |
| 38 | 1 | equemene | * ( 1 + ( m - 1 )*abs( INCX ) ). |
| 39 | 1 | equemene | * Before entry, the incremented array X must contain the m |
| 40 | 1 | equemene | * element vector x. |
| 41 | 1 | equemene | * Unchanged on exit. |
| 42 | 1 | equemene | * |
| 43 | 1 | equemene | * INCX - INTEGER. |
| 44 | 1 | equemene | * On entry, INCX specifies the increment for the elements of |
| 45 | 1 | equemene | * X. INCX must not be zero. |
| 46 | 1 | equemene | * Unchanged on exit. |
| 47 | 1 | equemene | * |
| 48 | 1 | equemene | * Y - DOUBLE PRECISION array of dimension at least |
| 49 | 1 | equemene | * ( 1 + ( n - 1 )*abs( INCY ) ). |
| 50 | 1 | equemene | * Before entry, the incremented array Y must contain the n |
| 51 | 1 | equemene | * element vector y. |
| 52 | 1 | equemene | * Unchanged on exit. |
| 53 | 1 | equemene | * |
| 54 | 1 | equemene | * INCY - INTEGER. |
| 55 | 1 | equemene | * On entry, INCY specifies the increment for the elements of |
| 56 | 1 | equemene | * Y. INCY must not be zero. |
| 57 | 1 | equemene | * Unchanged on exit. |
| 58 | 1 | equemene | * |
| 59 | 1 | equemene | * A - DOUBLE PRECISION array of DIMENSION ( LDA, n ). |
| 60 | 1 | equemene | * Before entry, the leading m by n part of the array A must |
| 61 | 1 | equemene | * contain the matrix of coefficients. On exit, A is |
| 62 | 1 | equemene | * overwritten by the updated matrix. |
| 63 | 1 | equemene | * |
| 64 | 1 | equemene | * LDA - INTEGER. |
| 65 | 1 | equemene | * On entry, LDA specifies the first dimension of A as declared |
| 66 | 1 | equemene | * in the calling (sub) program. LDA must be at least |
| 67 | 1 | equemene | * max( 1, m ). |
| 68 | 1 | equemene | * Unchanged on exit. |
| 69 | 1 | equemene | * |
| 70 | 1 | equemene | * |
| 71 | 1 | equemene | * Level 2 Blas routine. |
| 72 | 1 | equemene | * |
| 73 | 1 | equemene | * -- Written on 22-October-1986. |
| 74 | 1 | equemene | * Jack Dongarra, Argonne National Lab. |
| 75 | 1 | equemene | * Jeremy Du Croz, Nag Central Office. |
| 76 | 1 | equemene | * Sven Hammarling, Nag Central Office. |
| 77 | 1 | equemene | * Richard Hanson, Sandia National Labs. |
| 78 | 1 | equemene | * |
| 79 | 1 | equemene | * |
| 80 | 1 | equemene | * .. Parameters .. |
| 81 | 1 | equemene | DOUBLE PRECISION ZERO |
| 82 | 1 | equemene | PARAMETER (ZERO=0.0D+0) |
| 83 | 1 | equemene | * .. |
| 84 | 1 | equemene | * .. Local Scalars .. |
| 85 | 1 | equemene | DOUBLE PRECISION TEMP |
| 86 | 1 | equemene | INTEGER I,INFO,IX,J,JY,KX |
| 87 | 1 | equemene | * .. |
| 88 | 1 | equemene | * .. External Subroutines .. |
| 89 | 1 | equemene | EXTERNAL XERBLA |
| 90 | 1 | equemene | * .. |
| 91 | 1 | equemene | * .. Intrinsic Functions .. |
| 92 | 1 | equemene | INTRINSIC MAX |
| 93 | 1 | equemene | * .. |
| 94 | 1 | equemene | * |
| 95 | 1 | equemene | * Test the input parameters. |
| 96 | 1 | equemene | * |
| 97 | 1 | equemene | INFO = 0 |
| 98 | 1 | equemene | IF (M.LT.0) THEN |
| 99 | 1 | equemene | INFO = 1 |
| 100 | 1 | equemene | ELSE IF (N.LT.0) THEN |
| 101 | 1 | equemene | INFO = 2 |
| 102 | 1 | equemene | ELSE IF (INCX.EQ.0) THEN |
| 103 | 1 | equemene | INFO = 5 |
| 104 | 1 | equemene | ELSE IF (INCY.EQ.0) THEN |
| 105 | 1 | equemene | INFO = 7 |
| 106 | 1 | equemene | ELSE IF (LDA.LT.MAX(1,M)) THEN |
| 107 | 1 | equemene | INFO = 9 |
| 108 | 1 | equemene | END IF |
| 109 | 1 | equemene | IF (INFO.NE.0) THEN |
| 110 | 1 | equemene | CALL XERBLA('DGER ',INFO)
|
| 111 | 1 | equemene | RETURN |
| 112 | 1 | equemene | END IF |
| 113 | 1 | equemene | * |
| 114 | 1 | equemene | * Quick return if possible. |
| 115 | 1 | equemene | * |
| 116 | 1 | equemene | IF ((M.EQ.0) .OR. (N.EQ.0) .OR. (ALPHA.EQ.ZERO)) RETURN |
| 117 | 1 | equemene | * |
| 118 | 1 | equemene | * Start the operations. In this version the elements of A are |
| 119 | 1 | equemene | * accessed sequentially with one pass through A. |
| 120 | 1 | equemene | * |
| 121 | 1 | equemene | IF (INCY.GT.0) THEN |
| 122 | 1 | equemene | JY = 1 |
| 123 | 1 | equemene | ELSE |
| 124 | 1 | equemene | JY = 1 - (N-1)*INCY |
| 125 | 1 | equemene | END IF |
| 126 | 1 | equemene | IF (INCX.EQ.1) THEN |
| 127 | 1 | equemene | DO 20 J = 1,N |
| 128 | 1 | equemene | IF (Y(JY).NE.ZERO) THEN |
| 129 | 1 | equemene | TEMP = ALPHA*Y(JY) |
| 130 | 1 | equemene | DO 10 I = 1,M |
| 131 | 1 | equemene | A(I,J) = A(I,J) + X(I)*TEMP |
| 132 | 1 | equemene | 10 CONTINUE |
| 133 | 1 | equemene | END IF |
| 134 | 1 | equemene | JY = JY + INCY |
| 135 | 1 | equemene | 20 CONTINUE |
| 136 | 1 | equemene | ELSE |
| 137 | 1 | equemene | IF (INCX.GT.0) THEN |
| 138 | 1 | equemene | KX = 1 |
| 139 | 1 | equemene | ELSE |
| 140 | 1 | equemene | KX = 1 - (M-1)*INCX |
| 141 | 1 | equemene | END IF |
| 142 | 1 | equemene | DO 40 J = 1,N |
| 143 | 1 | equemene | IF (Y(JY).NE.ZERO) THEN |
| 144 | 1 | equemene | TEMP = ALPHA*Y(JY) |
| 145 | 1 | equemene | IX = KX |
| 146 | 1 | equemene | DO 30 I = 1,M |
| 147 | 1 | equemene | A(I,J) = A(I,J) + X(IX)*TEMP |
| 148 | 1 | equemene | IX = IX + INCX |
| 149 | 1 | equemene | 30 CONTINUE |
| 150 | 1 | equemene | END IF |
| 151 | 1 | equemene | JY = JY + INCY |
| 152 | 1 | equemene | 40 CONTINUE |
| 153 | 1 | equemene | END IF |
| 154 | 1 | equemene | * |
| 155 | 1 | equemene | RETURN |
| 156 | 1 | equemene | * |
| 157 | 1 | equemene | * End of DGER . |
| 158 | 1 | equemene | * |
| 159 | 1 | equemene | END |