From 5f052f8d98fe534a37a4c66e96e134e04fa21b87 Mon Sep 17 00:00:00 2001
From: Kistaro Windrider <kistaro@gmail.com>
Date: Sat, 18 Nov 2023 16:10:26 -0800
Subject: [PATCH] Add convenience functions for the "default" normal
 distribution and bidders distributed thereby.

---
 auctionsim/defaults.go   | 31 +++++++++++++++++++++++++++++++
 auctionsim/generators.go |  1 -
 2 files changed, 31 insertions(+), 1 deletion(-)
 create mode 100644 auctionsim/defaults.go

diff --git a/auctionsim/defaults.go b/auctionsim/defaults.go
new file mode 100644
index 0000000..dbcf2a8
--- /dev/null
+++ b/auctionsim/defaults.go
@@ -0,0 +1,31 @@
+package auctionsim
+
+import (
+	"math/rand"
+)
+
+/**
+ * NormalestDistribution returns a NormalDistribution with a new rand.Rand
+ * behind it (randomly seeded), with standard deviation of 1 and mean of 0.
+ */
+func NormalestDistribution() *NormalDistribution {
+	return &NormalDistribution{
+		Rand: rand.New(rand.NewSource(int64(rand.Uint64()))),
+		StdDev: 1,
+		Mean: 0,
+	}
+}
+
+/**
+ * NormalestBidderGenerator returns a BidderGenerator that returns an infinite
+ * number of Bidders with infinite cash, and values and errors normally
+ * distributed around 0.
+ */
+func NormalestBidderGenerator() BidderGenerator {
+	d := NormalestDistribution()
+	return &BiddersFromDistributions{
+		Values: d,
+		Irrationalities: d,
+		Bankrolls: ConstDistribution(math.Inf(1)),
+	}
+}
diff --git a/auctionsim/generators.go b/auctionsim/generators.go
index a67076a..e4c3827 100644
--- a/auctionsim/generators.go
+++ b/auctionsim/generators.go
@@ -79,7 +79,6 @@ func (n *NormalDistribution) Draw() (float64, bool) {
 	return n.Rand.NormFloat64() * n.StdDev + n.Mean, true
 }
 
-
 /**
  * ConstDistribution is a Distribution that always returns the same value.
  */