initial import

core/mathx/proba.go

@@ -0,0 +1,26 @@
+package mathx
+
+import (
+	"math/rand"
+	"sync"
+	"time"
+)
+
+type Proba struct {
+	// rand.New(...) returns a non thread safe object
+	r    *rand.Rand
+	lock sync.Mutex
+}
+
+func NewProba() *Proba {
+	return &Proba{
+		r: rand.New(rand.NewSource(time.Now().UnixNano())),
+	}
+}
+
+func (p *Proba) TrueOnProba(proba float64) (truth bool) {
+	p.lock.Lock()
+	truth = p.r.Float64() < proba
+	p.lock.Unlock()
+	return
+}