Annotation of rpl/lapack/lapack/zspmv.f, revision 1.1
1.1 ! bertrand 1: SUBROUTINE ZSPMV( UPLO, N, ALPHA, AP, X, INCX, BETA, Y, INCY )
! 2: *
! 3: * -- LAPACK auxiliary routine (version 3.2) --
! 4: * -- LAPACK is a software package provided by Univ. of Tennessee, --
! 5: * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
! 6: * November 2006
! 7: *
! 8: * .. Scalar Arguments ..
! 9: CHARACTER UPLO
! 10: INTEGER INCX, INCY, N
! 11: COMPLEX*16 ALPHA, BETA
! 12: * ..
! 13: * .. Array Arguments ..
! 14: COMPLEX*16 AP( * ), X( * ), Y( * )
! 15: * ..
! 16: *
! 17: * Purpose
! 18: * =======
! 19: *
! 20: * ZSPMV performs the matrix-vector operation
! 21: *
! 22: * y := alpha*A*x + beta*y,
! 23: *
! 24: * where alpha and beta are scalars, x and y are n element vectors and
! 25: * A is an n by n symmetric matrix, supplied in packed form.
! 26: *
! 27: * Arguments
! 28: * ==========
! 29: *
! 30: * UPLO (input) CHARACTER*1
! 31: * On entry, UPLO specifies whether the upper or lower
! 32: * triangular part of the matrix A is supplied in the packed
! 33: * array AP as follows:
! 34: *
! 35: * UPLO = 'U' or 'u' The upper triangular part of A is
! 36: * supplied in AP.
! 37: *
! 38: * UPLO = 'L' or 'l' The lower triangular part of A is
! 39: * supplied in AP.
! 40: *
! 41: * Unchanged on exit.
! 42: *
! 43: * N (input) INTEGER
! 44: * On entry, N specifies the order of the matrix A.
! 45: * N must be at least zero.
! 46: * Unchanged on exit.
! 47: *
! 48: * ALPHA (input) COMPLEX*16
! 49: * On entry, ALPHA specifies the scalar alpha.
! 50: * Unchanged on exit.
! 51: *
! 52: * AP (input) COMPLEX*16 array, dimension at least
! 53: * ( ( N*( N + 1 ) )/2 ).
! 54: * Before entry, with UPLO = 'U' or 'u', the array AP must
! 55: * contain the upper triangular part of the symmetric matrix
! 56: * packed sequentially, column by column, so that AP( 1 )
! 57: * contains a( 1, 1 ), AP( 2 ) and AP( 3 ) contain a( 1, 2 )
! 58: * and a( 2, 2 ) respectively, and so on.
! 59: * Before entry, with UPLO = 'L' or 'l', the array AP must
! 60: * contain the lower triangular part of the symmetric matrix
! 61: * packed sequentially, column by column, so that AP( 1 )
! 62: * contains a( 1, 1 ), AP( 2 ) and AP( 3 ) contain a( 2, 1 )
! 63: * and a( 3, 1 ) respectively, and so on.
! 64: * Unchanged on exit.
! 65: *
! 66: * X (input) COMPLEX*16 array, dimension at least
! 67: * ( 1 + ( N - 1 )*abs( INCX ) ).
! 68: * Before entry, the incremented array X must contain the N-
! 69: * element vector x.
! 70: * Unchanged on exit.
! 71: *
! 72: * INCX (input) INTEGER
! 73: * On entry, INCX specifies the increment for the elements of
! 74: * X. INCX must not be zero.
! 75: * Unchanged on exit.
! 76: *
! 77: * BETA (input) COMPLEX*16
! 78: * On entry, BETA specifies the scalar beta. When BETA is
! 79: * supplied as zero then Y need not be set on input.
! 80: * Unchanged on exit.
! 81: *
! 82: * Y (input/output) COMPLEX*16 array, dimension at least
! 83: * ( 1 + ( N - 1 )*abs( INCY ) ).
! 84: * Before entry, the incremented array Y must contain the n
! 85: * element vector y. On exit, Y is overwritten by the updated
! 86: * vector y.
! 87: *
! 88: * INCY (input) INTEGER
! 89: * On entry, INCY specifies the increment for the elements of
! 90: * Y. INCY must not be zero.
! 91: * Unchanged on exit.
! 92: *
! 93: * =====================================================================
! 94: *
! 95: * .. Parameters ..
! 96: COMPLEX*16 ONE
! 97: PARAMETER ( ONE = ( 1.0D+0, 0.0D+0 ) )
! 98: COMPLEX*16 ZERO
! 99: PARAMETER ( ZERO = ( 0.0D+0, 0.0D+0 ) )
! 100: * ..
! 101: * .. Local Scalars ..
! 102: INTEGER I, INFO, IX, IY, J, JX, JY, K, KK, KX, KY
! 103: COMPLEX*16 TEMP1, TEMP2
! 104: * ..
! 105: * .. External Functions ..
! 106: LOGICAL LSAME
! 107: EXTERNAL LSAME
! 108: * ..
! 109: * .. External Subroutines ..
! 110: EXTERNAL XERBLA
! 111: * ..
! 112: * .. Executable Statements ..
! 113: *
! 114: * Test the input parameters.
! 115: *
! 116: INFO = 0
! 117: IF( .NOT.LSAME( UPLO, 'U' ) .AND. .NOT.LSAME( UPLO, 'L' ) ) THEN
! 118: INFO = 1
! 119: ELSE IF( N.LT.0 ) THEN
! 120: INFO = 2
! 121: ELSE IF( INCX.EQ.0 ) THEN
! 122: INFO = 6
! 123: ELSE IF( INCY.EQ.0 ) THEN
! 124: INFO = 9
! 125: END IF
! 126: IF( INFO.NE.0 ) THEN
! 127: CALL XERBLA( 'ZSPMV ', INFO )
! 128: RETURN
! 129: END IF
! 130: *
! 131: * Quick return if possible.
! 132: *
! 133: IF( ( N.EQ.0 ) .OR. ( ( ALPHA.EQ.ZERO ) .AND. ( BETA.EQ.ONE ) ) )
! 134: $ RETURN
! 135: *
! 136: * Set up the start points in X and Y.
! 137: *
! 138: IF( INCX.GT.0 ) THEN
! 139: KX = 1
! 140: ELSE
! 141: KX = 1 - ( N-1 )*INCX
! 142: END IF
! 143: IF( INCY.GT.0 ) THEN
! 144: KY = 1
! 145: ELSE
! 146: KY = 1 - ( N-1 )*INCY
! 147: END IF
! 148: *
! 149: * Start the operations. In this version the elements of the array AP
! 150: * are accessed sequentially with one pass through AP.
! 151: *
! 152: * First form y := beta*y.
! 153: *
! 154: IF( BETA.NE.ONE ) THEN
! 155: IF( INCY.EQ.1 ) THEN
! 156: IF( BETA.EQ.ZERO ) THEN
! 157: DO 10 I = 1, N
! 158: Y( I ) = ZERO
! 159: 10 CONTINUE
! 160: ELSE
! 161: DO 20 I = 1, N
! 162: Y( I ) = BETA*Y( I )
! 163: 20 CONTINUE
! 164: END IF
! 165: ELSE
! 166: IY = KY
! 167: IF( BETA.EQ.ZERO ) THEN
! 168: DO 30 I = 1, N
! 169: Y( IY ) = ZERO
! 170: IY = IY + INCY
! 171: 30 CONTINUE
! 172: ELSE
! 173: DO 40 I = 1, N
! 174: Y( IY ) = BETA*Y( IY )
! 175: IY = IY + INCY
! 176: 40 CONTINUE
! 177: END IF
! 178: END IF
! 179: END IF
! 180: IF( ALPHA.EQ.ZERO )
! 181: $ RETURN
! 182: KK = 1
! 183: IF( LSAME( UPLO, 'U' ) ) THEN
! 184: *
! 185: * Form y when AP contains the upper triangle.
! 186: *
! 187: IF( ( INCX.EQ.1 ) .AND. ( INCY.EQ.1 ) ) THEN
! 188: DO 60 J = 1, N
! 189: TEMP1 = ALPHA*X( J )
! 190: TEMP2 = ZERO
! 191: K = KK
! 192: DO 50 I = 1, J - 1
! 193: Y( I ) = Y( I ) + TEMP1*AP( K )
! 194: TEMP2 = TEMP2 + AP( K )*X( I )
! 195: K = K + 1
! 196: 50 CONTINUE
! 197: Y( J ) = Y( J ) + TEMP1*AP( KK+J-1 ) + ALPHA*TEMP2
! 198: KK = KK + J
! 199: 60 CONTINUE
! 200: ELSE
! 201: JX = KX
! 202: JY = KY
! 203: DO 80 J = 1, N
! 204: TEMP1 = ALPHA*X( JX )
! 205: TEMP2 = ZERO
! 206: IX = KX
! 207: IY = KY
! 208: DO 70 K = KK, KK + J - 2
! 209: Y( IY ) = Y( IY ) + TEMP1*AP( K )
! 210: TEMP2 = TEMP2 + AP( K )*X( IX )
! 211: IX = IX + INCX
! 212: IY = IY + INCY
! 213: 70 CONTINUE
! 214: Y( JY ) = Y( JY ) + TEMP1*AP( KK+J-1 ) + ALPHA*TEMP2
! 215: JX = JX + INCX
! 216: JY = JY + INCY
! 217: KK = KK + J
! 218: 80 CONTINUE
! 219: END IF
! 220: ELSE
! 221: *
! 222: * Form y when AP contains the lower triangle.
! 223: *
! 224: IF( ( INCX.EQ.1 ) .AND. ( INCY.EQ.1 ) ) THEN
! 225: DO 100 J = 1, N
! 226: TEMP1 = ALPHA*X( J )
! 227: TEMP2 = ZERO
! 228: Y( J ) = Y( J ) + TEMP1*AP( KK )
! 229: K = KK + 1
! 230: DO 90 I = J + 1, N
! 231: Y( I ) = Y( I ) + TEMP1*AP( K )
! 232: TEMP2 = TEMP2 + AP( K )*X( I )
! 233: K = K + 1
! 234: 90 CONTINUE
! 235: Y( J ) = Y( J ) + ALPHA*TEMP2
! 236: KK = KK + ( N-J+1 )
! 237: 100 CONTINUE
! 238: ELSE
! 239: JX = KX
! 240: JY = KY
! 241: DO 120 J = 1, N
! 242: TEMP1 = ALPHA*X( JX )
! 243: TEMP2 = ZERO
! 244: Y( JY ) = Y( JY ) + TEMP1*AP( KK )
! 245: IX = JX
! 246: IY = JY
! 247: DO 110 K = KK + 1, KK + N - J
! 248: IX = IX + INCX
! 249: IY = IY + INCY
! 250: Y( IY ) = Y( IY ) + TEMP1*AP( K )
! 251: TEMP2 = TEMP2 + AP( K )*X( IX )
! 252: 110 CONTINUE
! 253: Y( JY ) = Y( JY ) + ALPHA*TEMP2
! 254: JX = JX + INCX
! 255: JY = JY + INCY
! 256: KK = KK + ( N-J+1 )
! 257: 120 CONTINUE
! 258: END IF
! 259: END IF
! 260: *
! 261: RETURN
! 262: *
! 263: * End of ZSPMV
! 264: *
! 265: END
CVSweb interface <joel.bertrand@systella.fr>
![[BACK]](/cvsweb/icons/back.gif){kind=icon}
Return to zspmv.f CVS log ![[TXT]](/cvsweb/icons/text.gif){kind=icon}
![[DIR]](/cvsweb/icons/dir.gif){kind=icon}
Up to [local] / rpl / lapack / lapack