From 79843b51267d7a8faf8e9dcee09fa5e167373e6d Mon Sep 17 00:00:00 2001
From: Mike Buland <eichlan@xagasoft.com>
Date: Fri, 9 Nov 2012 18:15:04 +0000
Subject: Added seed parameter to constructor of two PRNGs.  Also fixed
 horrible mistake in RandomBasic.

---
 src/stable/randombasic.cpp | 11 ++++++-----
 src/stable/randombasic.h   | 16 ++++++++++++++--
 src/stable/randomcmwc.cpp  |  3 ++-
 src/stable/randomcmwc.h    |  2 +-
 src/tests/random.cpp       |  2 +-
 5 files changed, 24 insertions(+), 10 deletions(-)

(limited to 'src')

diff --git a/src/stable/randombasic.cpp b/src/stable/randombasic.cpp
index e253b70..fe8843b 100644
--- a/src/stable/randombasic.cpp
+++ b/src/stable/randombasic.cpp
@@ -7,10 +7,11 @@
 
 #include "bu/randombasic.h"
 
-Bu::RandomBasic::RandomBasic() :
-    a( 6364136223846793005ll ),
-    c( 1442695040888963407ll ),
-    x( 0 )
+#define a (6364136223846793005ll)
+#define c (1442695040888963407ll)
+
+Bu::RandomBasic::RandomBasic( int32_t iSeed ) :
+    x( iSeed )
 {
 }
 
@@ -20,7 +21,7 @@ Bu::RandomBasic::~RandomBasic()
 
 void Bu::RandomBasic::seed( int32_t iSeed )
 {
-    c = iSeed;
+    x = iSeed;
 }
 
 int32_t Bu::RandomBasic::rand()
diff --git a/src/stable/randombasic.h b/src/stable/randombasic.h
index 4d1c2f8..c9b7072 100644
--- a/src/stable/randombasic.h
+++ b/src/stable/randombasic.h
@@ -11,10 +11,22 @@
 
 namespace Bu
 {
+    /**
+     * Basic Linear Congruential Generator.  This is one of the simplest and
+     * most common pseudo-random number generators out there.  It's simple,
+     * fast, and does a decent job if you don't have any stastistical
+     * requirements other than "random looking."  This is the algorithm included
+     * as the default random number generator in most standard libraries,
+     * although this one uses larger numbers internally, has a longer period,
+     * and more even distrubition of randomness accross it's bits than most
+     * implementations.
+     *
+     * The base values were published by Donald Knuth.
+     */
     class RandomBasic : public RandomBase
     {
     public:
-        RandomBasic();
+        RandomBasic( int32_t iSeed=0 );
         virtual ~RandomBasic();
 
         virtual void seed( int32_t iSeed );
@@ -22,7 +34,7 @@ namespace Bu
         virtual int32_t rand();
 
     private:
-        int64_t a, c, x;
+        int64_t x;
     };
 };
 
diff --git a/src/stable/randomcmwc.cpp b/src/stable/randomcmwc.cpp
index 1d4a913..b1c3cdb 100644
--- a/src/stable/randomcmwc.cpp
+++ b/src/stable/randomcmwc.cpp
@@ -11,11 +11,12 @@
 
 #define PHI 0x9e3779b9
 
-Bu::RandomCmwc::RandomCmwc() :
+Bu::RandomCmwc::RandomCmwc( int32_t iSeed ) :
     q( 0 ),
     c( 362436 )
 {
     q = new uint32_t[4096];
+    seed( iSeed );
 }
 
 Bu::RandomCmwc::~RandomCmwc()
diff --git a/src/stable/randomcmwc.h b/src/stable/randomcmwc.h
index 547b5bb..50eb8c4 100644
--- a/src/stable/randomcmwc.h
+++ b/src/stable/randomcmwc.h
@@ -14,7 +14,7 @@ namespace Bu
     class RandomCmwc : public RandomBase
     {
     public:
-        RandomCmwc();
+        RandomCmwc( int32_t iSeed=0 );
         virtual ~RandomCmwc();
 
         virtual void seed( int32_t iSeed );
diff --git a/src/tests/random.cpp b/src/tests/random.cpp
index e48c543..95cdb0a 100644
--- a/src/tests/random.cpp
+++ b/src/tests/random.cpp
@@ -15,7 +15,7 @@ void coverage()
     uint32_t uBucket[78];
     memset( uBucket, 0, sizeof(uint32_t)*78 );
 
-    for( int j = 0; j < 1000000; j++ )
+    for( int j = 0; j < 1000; j++ )
     {
         uBucket[(int)(((uint32_t)rand.rand())/(double)(0xfffffffful)*78+0.5)]++;
     }
-- 
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