From 8fa799d83dd1342550066ee9aec63cfa67198720 Mon Sep 17 00:00:00 2001
From: Peter Hurck <peter.hurck@glasgow.ac.uk>
Date: Fri, 22 Mar 2024 09:03:28 -0400
Subject: [PATCH] Pass seed from ProductionMechanism to BreitWignerGenerator

---
 src/libraries/AMPTOOLS_MCGEN/BreitWignerGenerator.cc | 9 ++++++---
 src/libraries/AMPTOOLS_MCGEN/BreitWignerGenerator.h  | 2 +-
 src/libraries/AMPTOOLS_MCGEN/ProductionMechanism.cc  | 5 +++--
 src/libraries/AMPTOOLS_MCGEN/ProductionMechanism.h   | 2 ++
 4 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/src/libraries/AMPTOOLS_MCGEN/BreitWignerGenerator.cc b/src/libraries/AMPTOOLS_MCGEN/BreitWignerGenerator.cc
index d856f43a3..04bf24707 100644
--- a/src/libraries/AMPTOOLS_MCGEN/BreitWignerGenerator.cc
+++ b/src/libraries/AMPTOOLS_MCGEN/BreitWignerGenerator.cc
@@ -4,6 +4,7 @@
 #include <cassert>
 
 #include "AMPTOOLS_MCGEN/BreitWignerGenerator.h"
+#include "TRandom3.h"
 
 const double BreitWignerGenerator::kPi = 3.14159;
 
@@ -12,10 +13,12 @@ m_mass( 0 ),
 m_width( 0 )
 {}
 
-BreitWignerGenerator::BreitWignerGenerator( double mass, double width ) :
+BreitWignerGenerator::BreitWignerGenerator( double mass, double width, int seed ) :
 m_mass( mass ),
 m_width( width )
-{}
+{
+    gRandom->SetSeed( seed );
+}
 
 pair< double, double >
 BreitWignerGenerator::operator()() const
@@ -61,5 +64,5 @@ BreitWignerGenerator::pdf( double s ) const {
 double
 BreitWignerGenerator::random( double low, double hi ) const {
 	
-	return( ( hi - low ) * drand48() + low );
+	return( ( hi - low ) * gRandom->Uniform() + low );
 }
diff --git a/src/libraries/AMPTOOLS_MCGEN/BreitWignerGenerator.h b/src/libraries/AMPTOOLS_MCGEN/BreitWignerGenerator.h
index 6e1b4778d..c39a2bd62 100644
--- a/src/libraries/AMPTOOLS_MCGEN/BreitWignerGenerator.h
+++ b/src/libraries/AMPTOOLS_MCGEN/BreitWignerGenerator.h
@@ -12,7 +12,7 @@ class BreitWignerGenerator
         
         BreitWignerGenerator();
         
-        BreitWignerGenerator( double mass, double width );
+        BreitWignerGenerator( double mass, double width, int seed = 0 );
         
         // output of the generation is a pair of doubles
         // the first is the mass and the second is the weight
diff --git a/src/libraries/AMPTOOLS_MCGEN/ProductionMechanism.cc b/src/libraries/AMPTOOLS_MCGEN/ProductionMechanism.cc
index 197e6a834..1b00a7f9e 100644
--- a/src/libraries/AMPTOOLS_MCGEN/ProductionMechanism.cc
+++ b/src/libraries/AMPTOOLS_MCGEN/ProductionMechanism.cc
@@ -20,7 +20,8 @@ m_highMass( 0 ),
 m_slope( slope ),
 m_lowT( 0 ),
 m_highT( 12 ),
-m_lastWeight( 1. )
+m_lastWeight( 1. ),
+m_seed( seed )
 {	
   // kMZ = 108.;      //  mass of Sn116 
   kMZ = 208.*0.931494;      //  use mass of Pb as it is in the particle table
@@ -210,7 +211,7 @@ void
 ProductionMechanism::addResonance( double mass, double width, double crossSec ){
   
   m_decGen.addChannel( m_bwGen.size(), crossSec );
-  m_bwGen.push_back( BreitWignerGenerator( mass, width ) );
+  m_bwGen.push_back( BreitWignerGenerator( mass, width, m_seed ) );
 }
 
 double
diff --git a/src/libraries/AMPTOOLS_MCGEN/ProductionMechanism.h b/src/libraries/AMPTOOLS_MCGEN/ProductionMechanism.h
index 3231809f8..89eeec346 100644
--- a/src/libraries/AMPTOOLS_MCGEN/ProductionMechanism.h
+++ b/src/libraries/AMPTOOLS_MCGEN/ProductionMechanism.h
@@ -53,6 +53,8 @@ class ProductionMechanism
 	double m_highT;
   
 	double m_recMass;
+
+	int m_seed;
 	
 	bool isBaryonResonance;