step: develop jit-bayes loop.

src/jit_bayes.nim

@@ -4,20 +4,10 @@ import sequtils
 import std/sugar
 import std/algorithm
 
-## Define type
+## Prediction type & helpers.
 type prediction = (string, float)
 # string represents a hypothesis, 
 # prediction represents the predictionability mass
-
-## Utils
-## Find index (or -1)
-proc findIndex(xs: seq[string], y: string): int =
-  for i, x in xs:
-    if x == y:
-      return i
-  return -1
-
-## Do simple predictions
 proc comparePredictions (x: prediction, y: prediction): int =
   let (_, p1) = x
   let (_, p2) = y
@@ -33,6 +23,14 @@ proc getHypothesis (t: prediction): string =
   let (h, _) = t
   return h
 
+## Utils
+## Find index (or -1)
+proc findIndex(xs: seq[string], y: string): int =
+  for i, x in xs:
+    if x == y:
+      return i
+  return -1
+
 ## Get sequences
 let file_path = "../data/one_to_three"
 ## let file_path = "../data/stripped"
@@ -71,12 +69,12 @@ proc getSequencesWithStart(seqs: seq[seq[string]], start: seq[string]): seq[seq[
   return continuations
 
 ## Pretty print sequences
-
 # var start = @["1", "2", "3", "4", "5"]
 # var continuations = getSequencesWithStart(seqs, start)
 # print continuations
 
 proc predictContinuation(seqs: seq[seq[string]], observations: seq[string]): seq[prediction] =
+  
   let continuations = getSequencesWithStart(seqs, observations)
   let l = observations.len
   var nexts: seq[string]
@@ -121,25 +119,63 @@ proc jitBayesLoop(
   initial_num_hypotheses: int,
   num_hypotheses_step: int,
 ) =
-  let l = observations.len
+  print "## Prediction with limited number of hypotheses (~JIT-Bayes)"
+  if n_observations_seen < 1:
+    echo "in jitBayesLoop function, n_observations_seen must be 1 or greater"
+    return 
 
-  var hypotheses = seqs[0..initial_num_hypotheses]
-  for i in n_observations_seen..<l:
+  var num_hypotheses = initial_num_hypotheses
+  var hypotheses = seqs[0..<num_hypotheses]
+  
+  let l = observations.len
+  for i in n_observations_seen..<l: # to do: make so that this can start at 0.
     let predictions = predictContinuation(hypotheses, observations[0..<i])
-    echo "Prediction after seeing ", i, " observations: ", observations[0..<i]
+    echo "### Prediction after seeing ", i, " observations: ", observations[0..<i]
     print predictions
     
-    ## let possible_continuations = predictions.map()
+    let correct_continuation = observations[i]
+    let considered_continuations = predictions.map(prediction => getHypothesis(prediction))
+    let correct_continuation_index = findIndex(considered_continuations, correct_continuation)
+
+    if correct_continuation_index == -1:
+      echo "Correct continuation not found in set of hypotheses of size ", num_hypotheses, "/", seqs.len, ". Increasing size of the set of hypotheses."
+
+      var found_concordant_hypothesis = false
+      var concordant_hypotheses: seq[seq[string]]
+      
+      while (not found_concordant_hypothesis) and ( num_hypotheses < seqs.len ):
+        num_hypotheses = num_hypotheses + num_hypotheses_step
+        if num_hypotheses > seqs.len:
+          num_hypotheses = seqs.len
+        hypotheses = seqs[0..<num_hypotheses]
+        concordant_hypotheses = filter(hypotheses, proc(h: seq[string]): bool = (h.len > i) and h[i] == observations[i])
+        if concordant_hypotheses.len > 0:
+          found_concordant_hypothesis = true
+
+      if not found_concordant_hypothesis:
+        echo "Increased number of hypotheses to ", num_hypotheses, ", but didn't find any hypotheses concordant with observations. Giving up."
+        return
+      else:
+        echo "Increased number of hypotheses to ", num_hypotheses, ", and found ", concordant_hypotheses.len, " concordant hypotheses. Continuing"
+
+    else:
+      echo "Correct continuation was ", correct_continuation
+      echo "It was assigned a probability of ", getProbability(predictions[correct_continuation_index])
+
+    echo ""
 
 ## Display outputs
-var observations = @["1", "2", "3", "4", "5", "6"]
-echo "Initial sequence", observations
+echo ""
 
-print "Full prediction with access to all hypotheses (~Solomonoff)"
+## var observations = @["1", "2", "3", "4", "5", "6"]
+var observations = @["1", "2", "3", "109", "5", "6"]
+echo "## Full prediction with access to all hypotheses (~Solomonoff)"
+echo "## Initial sequence: ", observations
 let continuation_probabilities = predictContinuation(seqs, observations)
 print continuation_probabilities
+echo ""
 
-print "Prediction with limited number of hypotheses (~JIT-Bayes)"
-jitBayesLoop(seqs, observations, 3, 1_000, 1_000)
+jitBayesLoop(seqs, observations, 3, 1_000, 2_000)
 
+echo ""