# prog1a.mpl -- Determine Machine Epsilon
# Written Sep 20, 2002 by Eric Olson for Mathematics 483
#
# For more information see Step 3 in First Steps in Numerical
# Analysis, 2nd Edition, by Hosking, Joe, Joyce and Turner

kernelopts(printbytes=false):

maxdelta:=proc(x::float)
	local a,b,delta,deold,r1;
	a:=0.0;
	b:=x;
	deold:=a;
	while true do
		delta:=(a+b)/2.0;
		if(deold=delta) then break fi;
		r1:=x+delta;
		if(r1=x) then a:=delta else b:=delta fi;
		deold:=delta;
	od;
	a;
end:

printf("Prog1a.mpl -- Determine Machine Epsilon\n\n");

Digits:=10:
printf("Using Digits=%d floating point.\n\n",Digits);

for x in [1.0,2.0,3.0,4.0,5.0,10.0,100.0,1000.0] do
	delta:=maxdelta(x);
	printf("x=%g d1=%g\n",x,delta);
od: