simple pseudo-random number generator

[miriam_e]

Found a really interesting pseudo-random number generator that simulates the roll of six-sided dice. It was on the Wikipedia page for the TI-57 Texas Instruments programmable calculator. (It was my first computer. I still use an emulator of the TI-57 on my Android smartphone from time to time.)

π (pi)
+
RCL 0
=
yˣ
8
-
Int 
=
STO 0
x (multiply)
6
+
1
=
Int 
R/S (stop and start)
RST (reset back to step 00)

I rewrote it as an awk one-liner:

awk 'BEGIN{
   pi = 3.14159265358979323846264338327950 ;
   for (n=0;n<20;n++){
      a=pi+b ; a=a**8 ; b= a-int(a) ; a=b*6+1 ;
      printf int(a) "  "
   }
   print ""
}'

Its output looked a bit biased to me so I wrote a quick check to see how frequently the different numbers come up in 2,000 rolls:

awk 'BEGIN{
   pi = 3.14159265358979323846264338327950 ;
   for (n=0;n<2000;n++){
      a=pi+b ; a=a**8 ; b= a-int(a) ; a=b*6+1 ; c[int(a)]++
   }
   print c[1], c[2], c[3], c[4], c[5], c[6]
}'

Surpisingly even spread:

354 316 346 327 331 326