Benchmark: timing 10000 iterations of Pcalc, manip...
     Pcalc:  2 wallclock secs ( 1.98 usr +  0.00 sys =  1.98 CPU) 
@ 5050.51/s (n=10000)
     manip: 49 wallclock secs (49.10 usr +  0.00 sys = 49.10 CPU) 
@ 203.67/s (n=10000)