init:{[npreds; nsubs; proba]
  prob:: proba
  p:: (npreds _draw 0) < proba
  myarray:: (4; nsubs) # (4*nsubs) _draw npreds
  myarray2:: + myarray
  answer:: nsubs # -2 
  answer2:: nsubs # -2 
  canswer:: nsubs # -2 / the result when using the c function
  idx:: !nsubs
  cr:: "./test.so"2:("cruntest";3)
  ncond:: 4 / number of predicates per subscription
}

/ folded version
runtest2:{[iterations]
  do[iterations
    answer2:: _n {x[& p[y[x]]]}/myarray
  ]
}

/ unfolded version
druntest1:{[iterations]
  do[iterations
    i: 0
    j: &p[myarray[0]]
    while[i < ncond
      j@: &p[myarray[i; j]]
      i+:1
    ]
    answer41:: j
  ]
}

/ while loop version
druntest2:{[iterations]
  do[iterations
    j: &p[myarray[0]]
    j@: &p[myarray[1; j]]
    j@: &p[myarray[2; j]]
    j@: &p[myarray[3; j]]
    answer42:: j
  ]
}

/ call the c function
crun:{[iterations]
  do[iterations
    cr[myarray;p;canswer]
  ]
}

run:{
  probabilities: 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.1 0.2 0.3 0.4 0.5 0.9 0.95 1.0
  runprob'probabilities
}

numiter: 1000

runprob:{[pro]
  init[5000; 3000; pro]
  ` 0: ("Probability is: "), ($pro), "\n"
  ` 0: ("k using a lamda expression \n")
  . "\\t runtest2[numiter];" / lamda expression
  ` 0: ("Probability is: "), ($pro), "\n"
  ` 0: ("k using a do loop \n")
  . "\\t druntest2[numiter];" / do loop
  ` 0: ("Probability is: "), ($pro), "\n"
  ` 0: ("k using an initialized while loop \n")
  . "\\t druntest1[numiter];" / initialized while loop version
  ` 0: ("Probability that predicate holds: "), ($pro), "\n"
  ` 0: ("C code unoptimized. \n")
  . "\\t crun[numiter];" / c function
}

run[]