HyperLogLog: make API use the P prefix in honor of Philippe Flajolet.

utils/hyperloglog/hll-err.rb

@@ -18,9 +18,9 @@ while true do
             elements << ele
             i += 1
         }
-        r.hlladd('hll',*elements)
+        r.padd('hll',*elements)
     }
-    approx = r.hllcount('hll')
+    approx = r.pcount('hll')
     abs_err = (approx-i).abs
     rel_err = 100.to_f*abs_err/i
     puts "#{i} vs #{approx}: #{rel_err}%"

utils/hyperloglog/hll-gnuplot-graph.rb

@@ -30,9 +30,9 @@ def run_experiment(r,seed,max,step)
                 elements << ele
                 i += 1
             }
-            r.hlladd('hll',*elements)
+            r.padd('hll',*elements)
         }
-        approx = r.hllcount('hll')
+        approx = r.pcount('hll')
         err = approx-i
         rel_err = 100.to_f*err/i
         samples << [i,rel_err]