subroutine shortestdist(my0,nx,pointy,
     &  pointx,xmin,xmax,nparams0,params0,
     &  iknowder0,shorty,shortx)
!find the point on the surface that has the shortest distance from a given point
      implicit none
      include 'leastdistance.h'
      integer my0,nx,nparams0,iknowder0
      double precision pointy(my0),shorty(my0),pointx(nx),
     &  shortx(nx),xmin(nx),xmax(nx),params0(nparams0)
!------------------Locals----------------------------------
      integer i,iwhichsolver,idowhat,notfound
      parameter(notfound=-9999)
      double precision s2,s2cp,
     &  f1dimsqsum_distcenter,f1dims2_distcenter,
     &  shortf(nx),dydxp(my0,(nx+nparams0)),xtol,ftol
      parameter(xtol=1.0d-10,ftol=1.0d-10)
      external distcentersys,fsqsum_distcenter,
     &  f1dimsqsum_distcenter,s2_distcenter,
     &  f1dims2_distcenter
!----------------------------------------------------------
      my=my0
      nparams=nparams0
      iknowder=iknowder0
      do i=1,nx
        targetx(i)=pointx(i)
      enddo
      do i=1,my
        targety(i)=pointy(i)
      enddo
      do i=1,nparams
        params(i)=params0(i)
      enddo
      call cpnonsyssolver(distcentersys,fsqsum_distcenter,
     &  f1dimsqsum_distcenter,xmin,pointx,shortx,xmax,
     &  shortf,nx,iwhichsolver)
      if(iwhichsolver.eq.notfound)then
        call s2_distcenter(nx,shortx,s2)
        s2cp=s2
        call cpnongradopt(nx,s2_distcenter,
     &    f1dims2_distcenter,shortx,xmin,xmax,ftol,s2)
        if(dabs(s2cp-s2).gt.ftol)then
          call cpRepeatCompassSearch(nx,shortx,s2,xmin,
     &      xmax,s2_distcenter,f1dims2_distcenter,xtol)
        endif
      endif
      idowhat=0
      call surffunc(my,shorty,nx,shortx,nparams,
     &  params,dydxp(1:my,1:(nx+nparams)),idowhat)
      return
      end subroutine shortestdist
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