Comments for generation of Markov chains file

Signed-off-by: ncordon <nacho.cordon.castillo@gmail.com>

Author: ncordon

src/sound/markov.go

@@ -27,16 +27,21 @@ func midiLoad(f string) []int {
 	return notes
 }
 
+// Transitions will store for a state (note identifier in midi) the
+// number of transitions to each other note, as observed in the midi file
 type Transitions map[int]map[int]uint32
+// A Markov chain is represented as a hash map with assigns state i -> [probability]
+// where the probability contains the state we can transition to as Key and an integer Value.
+// The array of probabilities is ordered increasingly by Value, where each value
+// represents an interval ]Value for prev state, Value] where the length of that
+// interval is proportional to the probability of going from i to Key
 type Markov map[int][]probability
 
 // Returns a Markov chain
 func NewMarkov(f string) Markov {
 	notes := midiLoad(f)
 	chain := make(Transitions)
 
-	// Parse the transitions, i.e. store for a state (note identifier in midi)
-	// the number of transitions to each other note, as observed in the midi file
 	previous := -1
 	for _, n := range notes {
 		if previous != -1 {
@@ -66,6 +71,8 @@ type probability struct {
 
 const probMax uint32 = (1 << 32) - 1
 
+// Parses the transitions for a state and generates
+// the probability itervals associated with it
 func getProbabilities(probs map[int]uint32) []probability {
 	var max uint32
 	var keys []int
@@ -104,6 +111,9 @@ func getProbabilities(probs map[int]uint32) []probability {
 	return pList
 }
 
+// Receives the initial state (as prev) and a random number, num,
+// in [0, max uint32]. We compute the state whose probability
+// interval contains num.
 func (m Markov) Get(prev int, num uint32) int {
 	chain := m[prev]
 	if chain == nil {
@@ -119,6 +129,8 @@ func (m Markov) Get(prev int, num uint32) int {
 	return m.Rand(num)
 }
 
+// Returns a random state from the Markov chain, given num
+// a random integer
 func (m Markov) Rand(num uint32) int {
 	// if the chain is not initialized return a valid note
 	if m == nil {