From e658ade6002ffba1beb52c9441018c0c8541abe2 Mon Sep 17 00:00:00 2001
From: Juan Batiz-Benet <juan@benet.ai>
Date: Wed, 20 Aug 2014 18:29:00 -0700
Subject: [PATCH] sigmoid strat placeholder
---
bitswap/strategy.go | 20 ++++++++++++++++++++
bitswap/strategy_test.go | 17 +++++++++++++++++
2 files changed, 37 insertions(+)
create mode 100644 bitswap/strategy.go
create mode 100644 bitswap/strategy_test.go
diff --git a/bitswap/strategy.go b/bitswap/strategy.go
new file mode 100644
index 000000000..6eb4c562f
--- /dev/null
+++ b/bitswap/strategy.go
@@ -0,0 +1,20 @@
+package bitswap
+
+import (
+ "math"
+)
+
+func probabilitySend(ratio float64) float64 {
+ x := 1 + math.Exp(6-3*ratio)
+ y := 1 / x
+ return 1 - y
+}
+
+type debtRatio struct {
+ BytesSent uint64
+ BytesRecv uint64
+}
+
+func (dr *debtRatio) Value() float64 {
+ return float64(dr.BytesSent) / float64(dr.BytesRecv+1)
+}
diff --git a/bitswap/strategy_test.go b/bitswap/strategy_test.go
new file mode 100644
index 000000000..a8de38ad7
--- /dev/null
+++ b/bitswap/strategy_test.go
@@ -0,0 +1,17 @@
+package bitswap
+
+import (
+ "testing"
+)
+
+func TestProbabilitySendDecreasesAsRatioIncreases(t *testing.T) {
+ grateful := debtRatio{BytesSent: 0, BytesRecv: 10000}
+ pWhenGrateful := probabilitySend(grateful.Value())
+
+ abused := debtRatio{BytesSent: 10000, BytesRecv: 0}
+ pWhenAbused := probabilitySend(abused.Value())
+
+ if pWhenGrateful < pWhenAbused {
+ t.Fail()
+ }
+}
--
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