#! /bin/ksh93
### ======================================================================
### Print a table of representable Fibonacci sequence values.  Among
### the various common UNIX shells in the Bourne and C shell families,
### only ksh93 (or later) provides floating-point arithmetic.
###
### Usage:
###	./Fibonacci3.ksh93 >outfile
###	or
###	ksh93 Fibonacci3.ksh93 >outfile
###
### [17-Aug-2005]
### ======================================================================

Fibonacci()
{
    typeset -E golden_ratio ratio
    typeset -i lo hi n
    lo=hi=n=1
    ## golden_ratio=$(((1 + sqrt(5)) / 2))
    golden_ratio=1.61803398874989484820458683436563816
    printf "%2d\t%11d\n" $n $lo
    while [[ $hi -gt 0 ]]
    do
	n=$n+1
	ratio=$hi
	ratio=$((ratio / lo))
	printf "%2d\t%11d\t%19.15f\t%19.15f\n" $n $hi $ratio $(($ratio - $golden_ratio))
	hi=$lo+$hi
	lo=$hi-$lo
    done
}

Fibonacci