dichotomic_search_r_desc.F

Go to the documentation of this file.

Copyright>        OpenRadioss
Copyright>        Copyright (C) 1986-2025 Altair Engineering Inc.
Copyright>
Copyright>        This program is free software: you can redistribute it and/or modify
Copyright>        it under the terms of the GNU Affero General Public License as published by
Copyright>        the Free Software Foundation, either version 3 of the License, or
Copyright>        (at your option) any later version.
Copyright>
Copyright>        This program is distributed in the hope that it will be useful,
Copyright>        but WITHOUT ANY WARRANTY; without even the implied warranty of
Copyright>        MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
Copyright>        GNU Affero General Public License for more details.
Copyright>
Copyright>        You should have received a copy of the GNU Affero General Public License
Copyright>        along with this program.  If not, see <https://www.gnu.org/licenses/>.
Copyright>
Copyright>
Copyright>        Commercial Alternative: Altair Radioss Software
Copyright>
Copyright>        As an alternative to this open-source version, Altair also offers Altair Radioss
Copyright>        software under a commercial license.  Contact Altair to discuss further if the
Copyright>        commercial version may interest you: https://www.altair.com/radioss/.
!||====================================================================
!||    dichotomic_search_r_desc       ../common_source/tools/search/dichotomic_search_r_desc.F
!||--- called by ------------------------------------------------------
!||    pblast_parameters__air_burst   ../common_source/modules/loads/pblast_mod.F90
!||====================================================================
      FUNCTION dichotomic_search_r_desc(VAL, ARRAY, LEN)
C-----------------------------------------------
C   D e s c r i p t i o n
C-----------------------------------------------
C This subroutines is searching and returning the index in integer array ARRAY(1:LEN)
C such as ARRAY(index)<= VAL <ARRAY(index)
C Dichotomic search is used
C-----------------------------------------------
C   P r e c o n d i t i on
C-----------------------------------------------
C ARRAY(1:LEN) must be sorted integers (descending order)
C LEN >= 1
C VAL is an integer
C-----------------------------------------------
C   I m p l i c i t   T y p e s
C-----------------------------------------------
#include      "implicit_f.inc"
C-----------------------------------------------
C   D u m m y   A r g u m e n t s
C-----------------------------------------------
        my_real, INTENT(IN) :: val
        INTEGER, INTENT(IN) :: len
        my_real, INTENT(IN) :: array(len)
        INTEGER :: dichotomic_search_r_desc
C-----------------------------------------------
C   L o c a l   V a r i a b l e s
C-----------------------------------------------
        INTEGER :: imid,istart,iend
C-----------------------------------------------
C   S o u r c e   L i n e s
C-----------------------------------------------
        istart = 1
        iend = len
        !VAL ABOVE UPPER BOUND
        IF(array(1)<val)THEN
          dichotomic_search_r_desc = 1
          RETURN
        ENDIF
        !VAL LOWER THAN LOWER BOUND
        IF(array(len)>val)THEN
          dichotomic_search_r_desc = len
          RETURN
        ENDIF
        !VAL IS BETWEEN THE BOUNDS
        DO WHILE (istart+1<iend)
          imid=(iend+istart)/2
          IF(array(imid) < val)THEN
            !FOCUS ON LEFT PART
            iend = imid
          ELSEIF(array(imid) > val)THEN
            !FOCUS ON RIGHT PART
            istart = imid
          ELSE
            !FOUND BY CHANCE NO NEED TO ITERATE MORE
            dichotomic_search_r_desc = imid
            RETURN
          ENDIF
        ENDDO
        dichotomic_search_r_desc = istart
        RETURN
      END FUNCTION dichotomic_search_r_desc
C-----------------------------------------------