92 lines
2.6 KiB
Fortran
92 lines
2.6 KiB
Fortran
DOUBLE PRECISION FUNCTION MB03MY( NX, X, INCX )
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C
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C SLICOT RELEASE 5.0.
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C
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C Copyright (c) 2002-2009 NICONET e.V.
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C
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C This program is free software: you can redistribute it and/or
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C modify it under the terms of the GNU General Public License as
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C published by the Free Software Foundation, either version 2 of
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C the License, or (at your option) any later version.
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C
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C This program is distributed in the hope that it will be useful,
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C but WITHOUT ANY WARRANTY; without even the implied warranty of
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C MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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C GNU General Public License for more details.
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C
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C You should have received a copy of the GNU General Public License
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C along with this program. If not, see
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C <http://www.gnu.org/licenses/>.
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C
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C PURPOSE
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C
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C To compute the absolute minimal value of NX elements in an array.
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C The function returns the value zero if NX < 1.
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C
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C ARGUMENTS
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C
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C NX (input) INTEGER
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C The number of elements in X to be examined.
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C
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C X (input) DOUBLE PRECISION array, dimension (NX * INCX)
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C The one-dimensional array of which the absolute minimal
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C value of the elements is to be computed.
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C This array is not referenced if NX < 1.
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C
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C INCX (input) INTEGER
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C The increment to be taken in the array X, defining the
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C distance between two consecutive elements. INCX >= 1.
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C INCX = 1, if all elements are contiguous in memory.
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C
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C NUMERICAL ASPECTS
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C
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C None.
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C
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C CONTRIBUTOR
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C
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C Release 3.0: V. Sima, Katholieke Univ. Leuven, Belgium, Mar. 1997.
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C Supersedes Release 2.0 routine MB03AZ by S. Van Huffel, Katholieke
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C University, Leuven, Belgium.
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C
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C REVISIONS
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C
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C June 16, 1997.
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C
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C KEYWORDS
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C
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C None.
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C
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C ******************************************************************
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C
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C .. Parameters ..
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DOUBLE PRECISION ZERO
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PARAMETER ( ZERO = 0.0D0 )
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C .. Scalar Arguments ..
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INTEGER INCX, NX
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C .. Array Arguments ..
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DOUBLE PRECISION X(*)
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C .. Local Scalars ..
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INTEGER I
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DOUBLE PRECISION DX
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C .. Intrinsic Functions ..
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INTRINSIC ABS
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C .. Executable Statements ..
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C
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C Quick return if possible.
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C
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IF ( NX.LE.0 ) THEN
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MB03MY = ZERO
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RETURN
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END IF
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C
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MB03MY = ABS( X(1) )
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C
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DO 20 I = 1+INCX, NX*INCX, INCX
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DX = ABS( X(I) )
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IF ( DX.LT.MB03MY ) MB03MY = DX
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20 CONTINUE
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C
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RETURN
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C *** Last line of MB03MY ***
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END
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