integer function fsrch(array,size,item)
      
      real array(size), item
      integer size   
      integer fib(48), bsrch2, k, discrd, index
      intent (in) :: size, array, item

      discrd = 0

c Precomputed Fibonacci numbers F0 up to F47. 

      data fib(1)/ 0/, fib(2)/ 1/, fib(3)/ 1/, fib(4)/ 2/, fib(5)/ 3/
     +fib(6)/ 5/, fib(7)/ 8/, fib(8)/ 13/, fib(9)/ 21/,fib(10)/ 34/
     +fib(11)/ 55/, fib(12)/ 89/, fib(13)/ 144/, fib(14)/ 233/
     +fib(15)/ 377/, fib(16)/ 610/, fib(17)/ 987/, fib(18)/ 1597/
     +fib(19)/ 2584/, fib(20)/ 4181/, fib(21)/ 6765/
     +fib(22)/ 10946/, fib(23)/ 17711/, fib(24)/ 28657/
     +fib(25)/ 46368/, fib(26)/ 75025/, fib(27)/ 121393/
     +fib(28)/ 196418/, fib(29)/ 317811/, fib(30)/ 514229/
     +fib(31)/ 832040/, fib(32)/ 1346269/, fib(33)/ 2178309/
     +fib(34)/ 3524578/, fib(35)/ 5702887/, fib(36)/ 9227465/
     +fib(37)/ 14930352/, fib(38)/ 24157817/, fib(39)/ 39088169/
     +fib(40)/ 63245986/, fib(41)/ 102334155/, fib(42)/ 165580141/
     +fib(43)/ 267914296/, fib(44)/ 433494437/, fib(45)/ 701408733/
     +fib(46)/ 1134903170/, fib(47)/ 1836311903/
     +fib(48)/ 2147483647/

c Find the smallest Fibonacci number that is greater or equal to array size.
      k=bsrch2(fib,48,size)

c If k = 0, stop. There is no match; the item is not in the array
   10 if (k .ne. 0) then
          index = fib(k-1) + discrd
c If element Fk-1 is beyond the end of the array, we pretend that the array 
c is padded with elements larger than the sought item.
          if (index .gt. size) then
             k = k-1
             goto 10
c Compare the item against element in Fk-1
c If the item is less than entry Fk-1, discard the elements from positions 
c Fk-1 to n. Set k = k - 1 and return to 10.
         else if (item .lt. array(index)) then 
             k = k-1
             goto 10
c If the item is greater than entry Fk-1, discard the elements from positions 
c 1 to Fk-1. Set k = k - 2, and return to 10.
         else if (item .gt. array(index)) then
             discrd = index
             k = k-2   
             goto 10
          end if
c If the item matches, stop.
      end if
c Return the result or the index of the nearest lower item if the item was not found.
      if (item .eq. array(index)) then
         fsrch = index
      else
         fsrch = discrd
      end if

      return
      end