C+
C NAME:
C	find_min_max.f
C PURPOSE:
C	Interpolate the longitude of ASHI to use in a sidereal time determination
C CATEGORY:
C	I/O
C CALLING SEQUENCE:
C	call find_min_max(XS1,YS1,NOBS,XSMAX,NIMAX,XSMIN,NIMIX,YSMAX,NIMAY,YSMIN,NIMIY,NXYM,NVAL)
C INPUTS:
C	XS1(NOSBM)        real	      Julian Date time to interpolate to
C	YS1(NOSBM)        real	      Julian dates of the tracked values where longitudes and latitudes exist
C     NOBS              integer     Number of star centroid locations
C     NXYM              integer     Maximum number of 
C     NVAL              integer     Number of values near maximum or minimum
C
C OUTPUTS:
C	XSMAX(NXYM,NVAL)	real		X Value Maximums
C     NIMAX(NXYM,NVAL)	integer	X Value maximum associated images    
C	XSMiN(NXYM,NVAL)	real		X Value Minimums
C     NIMIX(NXYM,NVAL)	integer	X Value minimum associated images 
C	YSMAX(NXYM,NVAL)	real		Y Value Maximums
C     NIMAY(NXYM,NVAL)	integer	Y Value maximum associated images    
C	YSMiN(NXYM,NVAL)	real		Y Value Minimums
C     NIMIY(NXYM,NVAL)	integer	Y Value minimum associated images 
C
C FUNCTIONS/SUBROUTINES:
C
C MODIFICATION HISTORY:
C	September-2022, Bernard Jackson (UCSD)
C-
	subroutine find_min_max(XS1,YS1,NOBS,XSMAX,NIMAX,XSMIN,NIMIX,YSMAX,NIMAY,YSMIN,NIMIY,NXYM,NVAL,distcx,distcy)
        real            XS1(NOBS),
     &                  YS1(NOBS),
     &                  XSMAX(NXYM,NVAL),
     &                  YSMAX(NXYM,NVAL),
     &                  XSMIN(NXYM,NVAL),
     &                  YSMIN(NXYM,NVAL)
     
        integer         NIMAX(NXYM,NVAL),
     &                  NIMAY(NXYM,NVAL),
     &                  NIMIX(NXYM,NVAL),
     &                  NIMIY(NXYM,NVAL)

          print*, ' Into find_Min_max'
           
            IX = 1
            NXMA = 0
            NYMA = 0
            NXMI = 0
            NYMI = 0
            NVAL2 = 20

            do I=1,NXYM
              do J=1,41
                XSMAX(I,J) = -9999.999
                YSMAX(I,J) = -9999.999
                XSMIN(I,J) = 9999.999
                YSMIN(I,J) = 9999.999             
                NIMAX(I,J) = 1
                NIMIX(I,J) = 1
                NIMAY(I,J) = 1
                NIMIY(I,J) = 1
              end do
            end do

C        Find X Min Max 
            XSMAL = XS1(20)
            YSMAL = YS1(20)
            XSBGL = XS1(20)
            YSBGL = YS1(20)
            I = 21
            do K=21,NOBS-21
              I = I + 1
              if(I.lt.NOBS-21) then
C                print*, I,XS1(I-20),XSBGL,XS1(I+20)
                if(XS1(I-20).lt.XSBGL.and.XS1(I+20).lt.XSBGL) then
                  NXMA = NXMA + 1
                  do J=1,NVAL
                    XSMAX(NXMA,J) = XS1(I+J-1-NVAL2)
                    NIMAX(NXMA,J) = I+J-1-NVAL2
C                    print*,'Xm',I,J,NXMA,I+J-1-NVAL2,XSMAX(NXMA,J),NIMAX(NXMA,J)
                  end do       
                  I = I + 41
                end if
                XSBGL = XS1(I)
              end if
            end do
            I = 21
            do K=21,NOBS-21
              I = I + 1
              if(I.lt.NOBS-21) then
                if(XS1(I-20).gt.XSMAL.and.XS1(I+20).gt.XSMAL) then
                  NXMI = NXMI + 1
                  do J=1,NVAL
                    XSMIN(NXMI,J) = XS1(I+J-1-NVAL2)
                    NIMIX(NXMI,J) = I+J-1-NVAL2
C                    print*,'Xi',I,J,NXMI,I+J-1-NVAL2,XSMIN(NXMI,J),NIMIX(NXMI,J)
                  end do
                  I = I + 41
                end if
              end if
              XSMAL = XS1(I)
            end do
C        Find Y Min Max 
            I = 21
            do K=21,NOBS-21
              I = I + 1
              if(I.lt.NOBS-21) then
C                print*, I,YS1(I-20),YSBGL,YS1(I+20)
                if(YS1(I-20).lt.YSBGL.and.YS1(I+20).lt.YSBGL) then
                  NYMA = NYMA + 1
                  do J=1,NVAL
                    YSMAX(NYMA,J) = YS1(I+J-1-NVAL2)
                    NIMAY(NYMA,J) = I+J-1-NVAL2
C                    print*,'Ym',I,J,NYMA,I+J-1-NVAL2,YSMAX(NYMA,J),NIMAY(NYMA,J)
                  end do       
                  I = I + 41
                end if
                YSBGL = YS1(I)
              end if
            end do
            I = 21
            do K=21,NOBS-21
              I = I + 1
              if(I.lt.NOBS-21) then
                if(YS1(I-20).gt.YSMAL.and.YS1(I+20).gt.YSMAL) then
                  NYMI = NYMI + 1
                  do J=1,NVAL
                    YSMIN(NYMI,J) = YS1(I+J-1-NVAL2)
                    NIMIY(NYMI,J) = I+J-1-NVAL2
C                    print*,'Yi',I,J,NYMI,I+J-1-NVAL2,YSMIN(NYMI,J),NIMIY(NYMI,J)
                  end do
                  I = I + 41
                end if
              end if
              YSMAL = YS1(I)
            end do

C        Print out X Min Max
            do I=1,NXYM
              do J=1,41
                if(XSMAX(I,J).ge.distcx) then
                  if(J.eq.1) then
C                    print*, ' '
C                    write(*,'(A,I4,A)') 'XMAX ',I,' IMAGE   MAX X'       
                  end if
                  if(J.eq.1.and.I.eq.1) write(*,'(A,I4,A)') 'XMAX ',I,' IMAGE   MAX X'
                  if(J.eq.1.and.I.eq.1) write(*,'(4X,I5,I6,F9.3)') J,NIMAX(I,J),XSMAX(I,J)
                end if
              end do
            end do
            do I=1,NXYM
              do J=1,41
                if(XSMIN(I,J).lt.distcx) then
                  if(J.eq.1) then
C                    print*, ' '
C                    write(*,'(A,I4,A)') 'XMIN ',I,' IMAGE   MIN X'      
                  end if
                  if(J.eq.1.and.I.eq.1) write(*,'(A,I4,A)') 'XMIN ',I,' IMAGE   MIN X'  
                  if(J.eq.1.and.I.eq.1) write(*,'(4X,I5,I6,F9.3)') J,NIMIX(I,J),XSMIN(I,J)
                end if
              end do
            end do
C        Print out Y Min Max 
            do I=1,NXYM
              do J=1,41
                if(YSMAX(I,J).ge.distcy) then
                  if(J.eq.1) then
C                    print*, ' '
C                    write(*,'(A,I4,A)') 'YMAX ',I,' IMAGE   MAX Y'       
                  end if
                  if(J.eq.1.and.I.eq.1) write(*,'(A,I4,A)') 'YMAX ',I,' IMAGE   MAX Y'
                  if(J.eq.1.and.I.eq.1) write(*,'(4X,I5,I6,F9.3)') J,NIMAY(I,J),YSMAX(I,J)
                end if
              end do
            end do
            do I=1,NXYM
              do J=1,41
                if(YSMIN(I,J).lt.distcy) then
                  if(J.eq.1) then
C                    print*, ' '
C                    write(*,'(A,I4,A)') 'YMIN ',I,' IMAGE   MIN Y'      
                  end if
                  if(J.eq.1.and.I.eq.1) write(*,'(A,I4,A)') 'YMIN ',I,' IMAGE   MIN Y'
                  if(J.eq.1.and.I.eq.1) write(*,'(4X,I5,I6,F9.3)') J,NIMIY(I,J),YSMIN(I,J)
                end if
              end do
            end do
            print*, 'end of find_min_max'
	  return
	end