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Example Specifications

This will contain some example specifications that accomplish something interesting

PI Estimate

This specification estimates the value of PI. It totally ignores the input records, but for each input record, the result gets more accurate. It doesn't get very accurate: You get about as many significant digits as you have in the number of input records, so processing a million records will get you less than 6 significant digits of PI -- more of less 3.141

  WORD 1 .                       # Just to make the records flow
  SET  "#0:=2*(frand()-0.5)"     # #0 is a random value between -1 and 1
  SET  "#1:=2*(frand()-0.5)"     # #1 is also random value between -1 and 1 
  SET  "#2:=pow(#0,2)+pow(#1,2)" # The distance of the (#0,#1) point from the origin, squared.
  SET  "#4:=#4+1"                # #4 just counts the records.
  IF   "#2<=1.0" THEN            # if the (#0,#1) point is within the unit circle...
     SET  "#3:=#3+1"             #    increment counter #3
  ENDIF 
EOF 
  PRINT  "4*#3/#4" 20            # The proportion of points within the unit circle multiplied 
                                 # by 4 is a good estimate of PI

Random Check

This specification doesn't need any input. It generates 10,000 random numbers between 0 and 9, and counts how may of them are 7. The expected value is, of course, 1000, and the standard deviation should be 30. This specification returns OK if the number of occurrences of 7 is within two standard deviations from the expected value. Note that this specification will terminate prematurely because of the while-guard, so it should be run with the --no-while-guard switch.

WHILE '#0<10000' DO
   PRINT 'fmap_sample(a,rand(10))' .
   SET '#0+=1'
DONE
SET '#1:=fmap_count(a,7)'
IF '#1 > 940 & #1 < 1060' THEN
   /OK/ 1
ELSE
   /NOT OK/ 1
ENDIF