Data update

Task/Pi/Standard-ML/pi.ml

@@ -0,0 +1,27 @@
+(* https://www.cs.ox.ac.uk/people/jeremy.gibbons/publications/spigot.pdf *)
+
+fun gibbons _ _ _ _ _ _ 0 = ()
+  | gibbons q r t k n l count =
+  let
+    val (q',r',t',k',n',l',count') =
+      if 4*q+r-t < n*t
+      then (10*q,10*(r-n*t),t,k,(10*(3*q+r)) div t-10*n,l,count-1) before print (IntInf.toString n)
+      else (q*k,(2*q+r)*l,t*l,k+1,(q*(7*k+2)+r*l) div (t*l),l+2,count)
+  in
+    gibbons q' r' t' k' n' l' count'
+  end
+
+fun doGibbons n = gibbons 1 0 1 1 3 3 n
+
+fun timeGibbons n =
+  let
+    val timer1 = Timer.startCPUTimer ()
+    val () = doGibbons n
+    val {usr=usr, sys=sys} = Timer.checkCPUTimer timer1
+  in
+    print "\n----------------------\n";
+    print ("usr: " ^ Time.toString usr ^ "\n");
+    print ("sys: " ^ Time.toString sys ^ "\n")
+  end
+
+fun main () = timeGibbons 5000