anchor.diff:      if(present(jlo)) klo = jlo
       ascnd=xvals(datalen).ge.xvals(1) ! True if ascending order of table, false otherwise.
       
  -    if(klo.le.0.or.klo.gt.datalen)then
  +    if(klo <= 0 .or. datalen<klo)then
          ! Input guess not useful. Go immediately to bisection.
          klo=0
          jhi=datalen+1
          goto 3
       endif
  +    
  +    ! use guessed position
       
       ! set the hunting increment.
       inc=1
  
positive.code:     integer,          intent(inout) :: jguess
      real(kind=fPrec), intent(in)    :: x, xvals(1:datalen), yvals(1:datalen)
  
      integer jj, jMin, jMax
      real(kind=fPrec) dy
  
      polinterp = zero ! -Wmaybe-uninitialized
  
negative.code:   ! ================================================================================================ !
    real(kind=fPrec) function polinterp(x,xvals,yvals,datalen,mpoints,jguess)
  
      use crcoall, only : lout
      use numerical_constants, only : zero
      implicit none
  
  