go: savepoint before deleting a few comments

go/squiggle.go

@@ -5,32 +5,32 @@ import "math"
 import "sync"
 import rand "math/rand/v2"
 
-type source = *rand.Rand
-type func64 = func(source) float64
+type src = *rand.Rand
+type func64 = func(src) float64
 
 // https://pkg.go.dev/math/rand/v2
 
-func sample_unit_uniform(r source) float64 {
+func sample_unit_uniform(r src) float64 {
 	return r.Float64()
 }
 
-func sample_unit_normal(r source) float64 {
+func sample_unit_normal(r src) float64 {
 	return r.NormFloat64()
 }
 
-func sample_uniform(start float64, end float64, r source) float64 {
+func sample_uniform(start float64, end float64, r src) float64 {
 	return sample_unit_uniform(r)*(end-start) + start
 }
 
-func sample_normal(mean float64, sigma float64, r source) float64 {
+func sample_normal(mean float64, sigma float64, r src) float64 {
 	return mean + sample_unit_normal(r)*sigma
 }
 
-func sample_lognormal(logmean float64, logstd float64, r source) float64 {
+func sample_lognormal(logmean float64, logstd float64, r src) float64 {
 	return (math.Exp(sample_normal(logmean, logstd, r)))
 }
 
-func sample_normal_from_90_ci(low float64, high float64, r source) float64 {
+func sample_normal_from_90_ci(low float64, high float64, r src) float64 {
 	var normal90 float64 = 1.6448536269514727
 	var mean float64 = (high + low) / 2.0
 	var std float64 = (high - low) / (2.0 * normal90)
@@ -38,7 +38,7 @@ func sample_normal_from_90_ci(low float64, high float64, r source) float64 {
 
 }
 
-func sample_to(low float64, high float64, r source) float64 {
+func sample_to(low float64, high float64, r src) float64 {
 	// Given a (positive) 90% confidence interval,
 	// returns a sample from a lognorma with a matching 90% c.i.
 	// Key idea: If we want a lognormal with 90% confidence interval [a, b]
@@ -49,7 +49,7 @@ func sample_to(low float64, high float64, r source) float64 {
 	return math.Exp(sample_normal_from_90_ci(loglow, loghigh, r))
 }
 
-func sample_mixture(fs []func64, weights []float64, r source) float64 {
+func sample_mixture(fs []func64, weights []float64, r src) float64 {
 
 	// fmt.Println("weights initially: ", weights)
 	var sum_weights float64 = 0
@@ -84,25 +84,27 @@ func sample_mixture(fs []func64, weights []float64, r source) float64 {
 
 }
 
-func slice_fill(xs []float64, fs func64, r source) {
+func slice_fill(xs []float64, fs func64, r src) {
 	for i := range xs {
 		xs[i] = fs(r)
 	}
 }
 
 func sample_parallel(f func64, n_samples int) []float64 {
-
+	var num_threads = 16
 	var xs = make([]float64, n_samples)
 	var wg sync.WaitGroup
-	var h = n_samples / 16
-	wg.Add(16)
-	for i := range 16 {
+	var h = n_samples / num_threads
+	wg.Add(num_threads)
+	for i := range num_threads {
 		var xs_i = xs[i*h : (i+1)*h]
-		go func() {
+		go func(f func64) {
 			defer wg.Done()
 			var r = rand.New(rand.NewPCG(uint64(i), uint64(i+1)))
-			slice_fill(xs_i, f, r)
-		}()
+			for i := range xs_i {
+				xs_i[i] = f(r)
+			}
+		}(f)
 	}
 
 	wg.Wait()
@@ -117,31 +119,29 @@ func main() {
 	var p_c float64 = p_a * p_b
 	ws := [4](float64){1 - p_c, p_c / 2, p_c / 4, p_c / 4}
 
-	sample_0 := func(r source) float64 { return 0 }
-	sample_1 := func(r source) float64 { return 1 }
-	sample_few := func(r source) float64 { return sample_to(1, 3, r) }
-	sample_many := func(r source) float64 { return sample_to(2, 10, r) }
+	sample_0 := func(r src) float64 { return 0 }
+	sample_1 := func(r src) float64 { return 1 }
+	sample_few := func(r src) float64 { return sample_to(1, 3, r) }
+	sample_many := func(r src) float64 { return sample_to(2, 10, r) }
 	fs := [4](func64){sample_0, sample_1, sample_few, sample_many}
 
-	model := func(r source) float64 { return sample_mixture(fs[0:], ws[0:], r) }
-	var n_samples int = 1_000_000
+	model := func(r src) float64 { return sample_mixture(fs[0:], ws[0:], r) }
+	n_samples := 1_000_000
 	xs := sample_parallel(model, n_samples)
-
 	var avg float64 = 0
 	for _, x := range xs {
 		avg += x
 	}
 	avg = avg / float64(n_samples)
 	fmt.Printf("Average: %v\n", avg)
-
 	/*
-
+		n_samples := 1_000_000
+		var r = rand.New(rand.NewPCG(uint64(1), uint64(2)))
 		var avg float64 = 0
 		for i := 0; i < n_samples; i++ {
-			avg += sample_mixture(fs[0:], ws[0:])
+			avg += sample_mixture(fs[0:], ws[0:], r)
 		}
 		avg = avg / float64(n_samples)
 		fmt.Printf("Average: %v\n", avg)
-
 	*/
 }