1 <chapter name="Update History">
3 <h2>Update History</h2>
5 These update notes describe major updates relative to the baseline
6 PYTHIA 8.100 version. However, they are less extensive than the
7 corresponding update notes for PYTHIA 6. There are three main
10 <li>The manual contained on these html/php pages is kept up to date.
11 (However, the "Brief Introduction" may not always be.)
13 <li>8.1 is a quite new code, so there are many minor changes that,
14 if all were to be documented, would hide the key ones.
16 <li>8.1 is not yet used for "mission critical" applications,
17 so there is less need to trace changed behaviour.
21 <h3>Main news by version</h3>
24 <li>8.101: 10 November 2007
26 <li>New option to initialize with arbitrary beam directions<br/>
27 <code>pythia.init( idA, idB, pxA, pyA, pzA, pxB, pyB, pzB)</code>
29 <li>The <code>LHAevnt</code> and <code>LHAinit</code> classes have been
30 joined into a new <code>LHAup</code> one, with new options that allow
31 the writing of a Les Houches Event File.
36 <li>8.102: 6 December 2007
38 <li>Limited capability to use two different <code>Pythia</code> instances
39 for signal + pileup event generation, see <code>main19.cc</code> for an
42 <li>Added capability to set <aloc href="BeamParameters">beam energy spread
43 and beam vertex</aloc>.
45 <b>Warning:</b> as a consequence, some settings names have been changed,
51 <li>8.103: 22 January 2008
53 <li>Updated HepMC conversion routine.
55 <li>In the <code>Event</code> class the <code>=</code> and
56 <code>=+</code> methods have been overloaded to allow the copying
57 or appending of event records. Illustrated in <code>main19.cc</code>.
62 <li>8.104: 14 February 2008
64 <li>Updated configure scripts.
66 <li>The <code>SusyLesHouches</code> class updated to handle
69 <li>The <code>forceHadronLevel()</code> method introduced for standalone
72 <li><code>main15.cc</code> illustrated how either full hadronization or
73 only decays of some particles can be looped over for the rest of the
76 <li>The html and php page formatting improved with
77 cascading style sheets.
79 <li>The static <code>ErrorMsg</code> class has been removed and
80 its functionality moved into the non-static <code>Info</code> class,
81 in the renamed Info file.
86 <li>8.105: 24 February 2008
88 <li>Further reduction of the use of static, with related code changes.
89 This should allow to have several almost independent <code>Pythia</code>
90 instances. Some static classes still remain, however, notably for
91 random number generation and particle properties.
93 <li>Several minor improvements and new options.
98 <li>8.106: 11 March 2008
100 <li>Improved handling of the Higgs width, relevant for massive and thereby
101 broad resonance shapes.
106 <li>8.107: 17 March 2008
108 <li>Correction in the event record, so that the beam particles in line
109 1 and 2 do not have any mother according to the <code>motherList</code>
110 method. Previously the "system" entry in line 0 was counted as their
111 mother, which gave rise to an unexpected extra vertex in the conversion
117 <li>8.108: 1 May 2008
119 <li>Support for HepMC version 1 is removed, to simplify the code and
120 reflect the evolution of the field.
122 <li>Status codes are stored in HepMC only as 1 for existing and 2 for
123 decayed or fragmented particles (whereas previously the original PYTHIA
124 codes were used for the latter).
126 <li>Parton densities are stored in HepMC as <ei>xf(x,Q^2)</ei>
127 rather than the <ei>f(x,Q^2)</ei> used in (some) previous versions.
129 <li>The SusyLesHouches class has ben updated so that reading is fully
130 compatible with the SLHA2 standard.
132 <li>The matrix elements for neutralino pair production have now been
133 completed and checked.
135 <li>A new compilation option <code>-Wshadow</code> is introduced and
136 code is rewritten at all places where this option gave warnings.
138 <li>Minor library correction to allow compilation with gcc 4.3.0.</li>
139 <li>Ensure that <ei>alpha_strong</ei> does not blow up, by introducing
140 a minimal scale somewhat above <ei>Lambda_3</ei> (roughly where
141 <ei>alpha_strong = 10</ei>).
143 <li>New methods <code>isValence1()</code> and <code>isValence2()</code>
144 in the <code>Info</code> class.
151 <h3>Changes among settings names</h3>
153 New capabilities are still being added, meaning new settings names.
154 It then may become preferable to rename existing settings to form
155 new logical groups. Here is a list of thise changes that have been
156 made since be 8.100 baseline version.
158 <li>A '*' is used as wildcard.
160 <li>Names within brackets denotes also new/changed functionality.
164 <table cellspacing="5">
165 <tr> <td>8.100 setting </td> <td>has been moved to </td> </tr>
166 <tr> <td>Beams:* </td> <td>BeamRemnants:* </td> </tr>
167 <tr> <td>Main:idA </td> <td>Beams:idA </td> </tr>
168 <tr> <td>Main:idB </td> <td>Beams:idB </td> </tr>
169 <tr> <td>Main:inCMframe </td> <td>(Beams:frameType) </td> </tr>
170 <tr> <td>Main:eCM </td> <td>Beams:eCM </td> </tr>
171 <tr> <td>Main:eA </td> <td>Beams:eA </td> </tr>
172 <tr> <td>Main:eB </td> <td>Beams:eB </td> </tr>
173 <tr> <td>Main:LHEF </td> <td>Beams:LHEF </td> </tr>
180 <!-- Copyright (C) 2008 Torbjorn Sjostrand -->