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first import of structure, PYTHIA8 and DELPHES
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2	<head>
3	<title>Program Flow</title>
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29
30	<h2>Program Flow</h2>
31
32	Recall that, to first order, the event generation process can be
33	subdivided into three stages:
34	<ol>
35	<li>Initializaion.</li>
36	<li>The event loop.</li>
37	<li>Finishing.</li>
38	</ol>
39	This is reflected in how the top-level <code>Pythia</code> class should
40	be used in the user-supplied main program, further outlined in the
41	following. Since the nature of the run is defined at the initialization
42	stage, this is where most of the PYTHIA user code has to be written.
43	So as not to confuse the reader unduly, the description of initialization
44	options has been subdivided into what would normally be used and what is
45	intended for more special applications.
46
47	<p/>
48	At the bottom of this webpge is a complete survey of all public
49	<code>Pythia</code> methods and data members, in a more formal style
50	than the task-oriented descriptions found in the preceding sections.
51	This offers complementary information.
52
53	<h3>Initialization - normal usage</h3>
54
55	<ol>
56
57	<li>
58	Already at the top of the main program file, you need to include the proper
59	header file
60	<pre>
61	#include "Pythia.h"
62	</pre>
63	To simplify typing, it also makes sense to declare
64	<pre>
65	using namespace Pythia8;
66	</pre>
67	</li>
68
69	<p/>
70	<li>
71	The first step is to create a generator object,
72	e.g. with
73	<pre>
74	Pythia pythia;
75	</pre>
76	It is this object that we will use from now on. Normally a run
77	will only contain one <code>Pythia</code> object. (But you can
78	use several <code>Pythia</code> objects, which then will be
79	independent of each other.)<br/>
80	By default all output from <code>Pythia</code> will be on the
81	<code>cout</code> stream, but the <code>list</code> methods below do
82	allow output to alternative streams or files.
83	</li>
84
85	<p/>
86	<li>
87	You next want to set up the character of the run.
88	The pages under the "Setup Run Tasks" heading in the index
89	describe all the options available (with some very few exceptions,
90	found on the other pages).
91	The default values and your modifications are stored in two databases,
92	one for <?php $filepath = $_GET["filepath"];
93	echo "<a href='SettingsScheme.php?filepath=".$filepath."' target='page'>";?>generic settings</a>
94	and one for <?php $filepath = $_GET["filepath"];
95	echo "<a href='ParticleDataScheme.php?filepath=".$filepath."' target='page'>";?>particle data</a>.
96	Both of these are initialized with their default values by the
97	<code>Pythia</code> constructor. The default values can then be
98	changed, primarily by one of the two ways below, or by a combination
99	of them.
100
101	<p/>
102	a) You can use the
103	<pre>
104	pythia.readString(string);
105	</pre>
106	method repeatedly to do a change of a property at a time.
107	The information in the string is case-insensitive, but upper- and
108	lowercase can be combined for clarity. The rules are that<br/>
109	(i) if the first nonblank character of the string is a letter
110	it is assumed to contain a setting, and is sent on to
111	<code>pythia.settings.readString(string)</code>;<br/>
112	(ii) if instead the string begins with a digit it is assumed to
113	contain particle data updates, and so sent on to
114	<code>pythia.particleData.readString(string)</code>;<br/>
115	(iii) if none of the above, the string is assumed to be a comment,
116	i.e. nothing will be done.<br/>
117	In the former two cases, a warning is issued whenever a string
118	cannot be recognized (maybe because of a spelling mistake).<br/>
119	Some examples would be
120	<pre>
121	pythia.readString("TimeShower:pTmin = 1.0");
122	pythia.readString("111:mayDecay = false");
123	</pre>
124	The <code>readString(string)</code> method is intended primarily for
125	a few changes. It can also be useful if you want to construct a
126	parser for input files that contain commands both to PYTHIA and to
127	other libraries.<br/>
128
129	<p/>
130	b) You can read in a file containing a list of those variables
131	you want to see changed, with a
132	<pre>
133	pythia.readFile(fileName);
134	</pre>
135	Each line in this file with be processes by the
136	<code>readString(string)</code> method introduced above. You can thus
137	freely mix comment lines and lines handed on to <code>Settings</code>
138	or to <code>ParticleData</code>.<br/>
139	This approach is better suited for more extensive changes than a direct
140	usage of <code>readString(string)</code>, and can also avoid having to
141	recompile and relink your main program between runs.<br/>
142	It is also possible to read input from an <code>istream</code>, by
143	default <code>cin</code>, rather than from a file. This may be convenient
144	if information is generated on-the-fly, within the same run.
145
146	<p/>
147	Changes are made sequentially in the order the commands are encountered
148	during execution, meaning that if a parameter is changed several times
149	it is the last one that counts. The two special
150	<code><?php $filepath = $_GET["filepath"];
151	echo "<a href='Tunes.php?filepath=".$filepath."' target='page'>";?>Tune:ee</a></code> and
152	<code><?php $filepath = $_GET["filepath"];
153	echo "<a href='Tunes.php?filepath=".$filepath."' target='page'>";?>Tune:pp</a></code>
154	modes are expanded to change several settings in one go, but these obey
155	the same ordering rules.
156	<br/>
157	</li>
158
159	<p/>
160	<li>
161	Next comes the initialization stage, where all
162	remaining details of the generation are to be specified.
163	There is one standard method to use for this
164
165	<p/>
166	<code>pythia.init();</code><br/>
167	with no arguments will read all relevant information from the
168	<code><?php $filepath = $_GET["filepath"];
169	echo "<a href='SettingsScheme.php?filepath=".$filepath."' target='page'>";?>Settings</a></code>
170	and <code><?php $filepath = $_GET["filepath"];
171	echo "<a href='ParticleDataScheme.php?filepath=".$filepath."' target='page'>";?>ParticleData</a></code>
172	databases. Specifically the setup of incoming beams and energies
173	is governed by the the beam parameters from the
174	<code><?php $filepath = $_GET["filepath"];
175	echo "<a href='BeamParameters.php?filepath=".$filepath."' target='page'>";?>Beams</a></code>
176	group of variables. If you don't change any of those you will
177	default to proton-proton collisions at 14 TeV, i.e. the nominal LHC
178	values.
179
180	<p/>
181	A few alternative forms are available, where the arguments of the
182	<code>init(...)</code> call can be used to set the beam parameters.
183	These alternatives are now deprecated, and will bew removed for
184	PYTHIA 8.2.
185
186	<p/>
187	a) <code>pythia.init( idA, idB, eCM);</code><br/>
188	lets you specify the identities and the CM energy of the two incoming
189	beam particles, with A (B) assumed moving in the <i>+z (-z)</i>
190	direction.
191
192	<p/>
193	b) <code>pythia.init( idA, idB, eA, eB);</code><br/>
194	is similar, but the two beam energies can be different, so the
195	collisions do not occur in the CM frame. If one of the beam energies
196	is below the particle mass you obtain a fixed-target topology.
197
198	<p/>
199	c) <code>pythia.init( idA, idB, pxA, pyA, pzA, pxB, pyB, pzB);</code><br/>
200	is similar, but here you provide the three-momenta
201	<i>(p_x, p_y, p_z)</i> of the two incoming particles,
202	to allow for arbitrary beam directions.
203
204	<p/>
205	d) <code>pythia.init(fileName);</code> <br/>
206	assumes a file in the <?php $filepath = $_GET["filepath"];
207	echo "<a href='LesHouchesAccord.php?filepath=".$filepath."' target='page'>";?>Les Houches
208	Event File</a> format is provided.
209
210	<p/>
211	e) <code>pythia.init( LHAup*);</code> <br/>
212	assumes <?php $filepath = $_GET["filepath"];
213	echo "<a href='LesHouchesAccord.php?filepath=".$filepath."' target='page'>";?>Les Houches Accord</a>
214	initialization and event information is available in an <code>LHAup</code>
215	class object, and that a pointer to this object is handed in.
216
217	<p/>
218	<li>
219	If you want to have a list of the generator and particle data used,
220	either only what has been changed or everything, you can use
221	<pre>
222	pythia.settings.listChanged();
223	pythia.settings.listAll();
224	pythia.particleData.listChanged();
225	pythia.particleData.listAll();
226	</pre>
227	</li>
228
229	</ol>
230
231	<h3>The event loop</h3>
232
233	<ol>
234
235	<li>
236	Inside the event generation loop you generate the
237	next event using the <code>next()</code> method,
238	<pre>
239	pythia.next();
240	</pre>
241	This method takes no arguments; everything has already been specified.
242	It does return a bool value, however, <code>false</code> when the
243	generation failed. This can be a "programmed death" when the
244	supply of input parton-level configurations on file is exhausted.
245	It can alternatively signal a failure of <code>Pythia</code> to
246	generate an event, or unphysical features in the event record at the
247	end of the generation step. It makes sense to allow a few <code>false</code>
248	values before a run is aborted, so long as the related faulty
249	events are skipped.
250	</li>
251
252	<p/>
253	<li>
254	The generated event is now stored in the <code>event</code>
255	object, of type <code><?php $filepath = $_GET["filepath"];
256	echo "<a href='EventRecord.php?filepath=".$filepath."' target='page'>";?>Event</a></code>,
257	which is a public member of <code>pythia</code>. You therefore have
258	access to all the tools described on the pages under the "Study Output"
259	header in the index. For instance, an event can be listed with
260	<code>pythia.event.list()</code>, the identity of the <i>i</i>'th
261	<?php $filepath = $_GET["filepath"];
262	echo "<a href='ParticleProperties.php?filepath=".$filepath."' target='page'>";?>particle</a> is given by
263	<code>pythia.event[i].id()</code>, and so on.<br/>
264	The hard process - roughly the information normally stored in the
265	Les Houches Accord event record - is available as a second object,
266	<code>process</code>, also of type <code>Event</code>.<br/>
267	A third useful public object is
268	<code><?php $filepath = $_GET["filepath"];
269	echo "<a href='EventInformation.php?filepath=".$filepath."' target='page'>";?>info</a></code>, which offers
270	a set of one-of-a kind pieces of information about the most recent
271	event.
272	</li>
273
274	</ol>
275
276	<h3>Finishing</h3>
277
278	<ol>
279
280	<li>At the end of the generation process, you can call
281	<pre>
282	pythia.stat();
283	</pre>
284	to get some run statistics, on cross sections and the number of errors
285	and warnings encountered. The alternative
286	<code>pythia.statistics(...);</code> is equivalent but deprecated.
287	</li>
288
289	</ol>
290
291	<h3>Advanced usage, mainly for initialization</h3>
292
293	A) Necessary data are automatically loaded when you use the
294	default PYTHIA installation directory structure and run the main
295	programs in the <code>examples</code> subdirectory. However, in the
296	general case, you must provide the path of the <code>xmldoc</code>
297	directory, where default settings and particle data are found.
298	This can be done in two ways.
299
300	<ol>
301
302	<li>
303	You can set the environment variable <code>PYTHIA8DATA</code> to
304	contain the location of the <code>xmldoc</code> directory. In the
305	<code>csh</code> and <code>tcsh</code> shells this could e.g. be
306	<pre>
307	setenv PYTHIA8DATA /home/myname/pythia81xx/xmldoc
308	</pre>
309	while in other shells it could be
310	<pre>
311	export PYTHIA8DATA=/home/myname/pythia81xx/xmldoc
312	</pre>
313	where xx is the subversion number.<br/>
314	Recall that environment variables set locally are only defined in the
315	current instance of the shell. The above lines should go into your
316	<code>.cshrc</code> and <code>.bashrc</code> files, respectively,
317	if you want a more permanant assignment.
318	</li>
319
320	<p/>
321	<li>
322	You can provide the path as argument to the <code>Pythia</code>
323	constructor, e.g.
324	<pre>
325	Pythia pythia("/home/myname/pythia81xx/xmldoc");
326	</pre>
327	</li>
328	</ol>
329	where again xx is the subversion number.<br/>
330	When <code>PYTHIA8DATA</code> is set it takes precedence, else
331	the path in the constructor is used, else one defaults to the
332	<code>../xmldoc</code> directory.
333
334	<p/>
335	B) You can override the default behaviour of PYTHIA not only by the
336	settings and particle data, but also by replacing some of the
337	PYTHIA standard routines by ones of your own. Of course, this is only
338	possible if your routines fit into the general PYTHIA framework.
339	Therefore they must be coded according to the the rules relevant
340	in each case, as a derived class of a PYTHIA base class, and a pointer
341	to such an object must be handed in by one of the methods below.
342	These calls must be made before the <code>pythia.init(...)</code> call.
343
344	<ol>
345
346	<li>
347	If you are not satisfied with the list of parton density functions that
348	are implemented internally or available via the LHAPDF interface
349	(see the <?php $filepath = $_GET["filepath"];
350	echo "<a href='PDFSelection.php?filepath=".$filepath."' target='page'>";?>PDF Selection</a> page), you
351	can suppy your own by a call to the <code>setPDFPtr(...)</code> method
352	<pre>
353	pythia.setPDFptr( pdfAPtr, pdfBPtr);
354	</pre>
355	where <code>pdfAPtr</code> and <code>pdfBPtr</code> are pointers to
356	two <code>Pythia</code> <?php $filepath = $_GET["filepath"];
357	echo "<a href='PartonDistributions.php?filepath=".$filepath."' target='page'>";?>PDF
358	objects</a>. Note that <code>pdfAPtr</code> and <code>pdfBPtr</code>
359	cannot point to the same object; even if the PDF set is the same,
360	two copies are needed to keep track of two separate sets of <i>x</i>
361	and density values.<br/>
362	If you further wish to use separate PDF's for the hard process of an
363	event than the ones being used for everything else, the extended form
364	<pre>
365	pythia.setPDFptr( pdfAPtr, pdfBPtr, pdfHardAPtr, pdfHardBPtr);
366	</pre>
367	allows you to specify those separately, and then the first two sets
368	would only be used for the showers and for multiparton interactions.
369	</li>
370
371	<p/>
372	<li>
373	If you want to link to an external generator that feeds in events
374	in the LHA format, you can call the <code>setLHAupPtr(...)</code>
375	method
376	<pre>
377	pythia.setLHAupPtr( lhaUpPtr);
378	</pre>
379	where the <code>lhaUpPtr</code> derives from the
380	<?php $filepath = $_GET["filepath"];
381	echo "<a href='LesHouchesAccord.php?filepath=".$filepath."' target='page'>";?>LHAup</a> base class.
382	</li>
383
384	<p/>
385	<li>
386	If you want to perform some particle decays with an
387	external generator, you can call the <code>setDecayPtr(...)</code>
388	method
389	<pre>
390	pythia.setDecayPtr( decayHandlePtr, particles);
391	</pre>
392	where the <code>decayHandlePtr</code> derives from the
393	<code><?php $filepath = $_GET["filepath"];
394	echo "<a href='ExternalDecays.php?filepath=".$filepath."' target='page'>";?>DecayHandler</a></code> base
395	class and <code>particles</code> is a vector of particle codes to be
396	handled.
397	</li>
398
399	<p/>
400	<li>
401	If you want to use an external random number generator,
402	you can call the <code>setRndmEnginePtr(...)</code> method
403	<pre>
404	pythia.setRndmEnginePtr( rndmEnginePtr);
405	</pre>
406	where <code>rndmEnginePtr</code> derives from the
407	<code><?php $filepath = $_GET["filepath"];
408	echo "<a href='RandomNumbers.php?filepath=".$filepath."' target='page'>";?>RndmEngine</a></code> base class.
409	The <code>Pythia</code> default random number generator is perfectly
410	good, so this is only intended for consistency in bigger frameworks.
411	</li>
412
413	<p/>
414	<li>
415	If you want to interrupt the evolution at various stages,
416	to interrogate the event and possibly veto it, or you want to
417	reweight the cross section, you can use
418	<pre>
419	pythia.setUserHooksPtr( userHooksPtr);
420	</pre>
421	where <code>userHooksPtr</code> derives from the
422	<code><?php $filepath = $_GET["filepath"];
423	echo "<a href='UserHooks.php?filepath=".$filepath."' target='page'>";?>UserHooks</a></code> base class.
424	</li>
425
426	<p/>
427	<li>
428	If you want to use your own merging scale definition for
429	matrix element + parton shower merging, you can call
430	<pre>
431	pythia.setMergingHooksPtr( mergingHooksPtr);
432	</pre>
433	where <code>mergingHooksPtr</code> derives from the
434	<code><?php $filepath = $_GET["filepath"];
435	echo "<a href='MatrixElementMerging.php?filepath=".$filepath."' target='page'>";?>MergingHooks</a></code> base class.
436	</li>
437
438	<p/>
439	<li>
440	If you want to use your own parametrization of beam momentum spread and
441	interaction vertex, rather than the provided simple Gaussian
442	parametrization (off by default), you can call
443	<pre>
444	pythia.setBeamShapePtr( beamShapePtr);
445	</pre>
446	where <code>beamShapePtr</code> derives from the
447	<code><?php $filepath = $_GET["filepath"];
448	echo "<a href='BeamShape.php?filepath=".$filepath."' target='page'>";?>BeamShape</a></code> base class.
449	</li>
450
451	<p/>
452	<li>
453	If you want to implement a cross section of your own, but still make use
454	of the built-in phase space selection machinery, you can use
455	<pre>
456	pythia.setSigmaPtr( sigmaPtr);
457	</pre>
458	where <code>sigmaPtr</code> of type <code>SigmaProcess*</code> is an
459	instance of a class derived from one of the <code>Sigma1Process</code>,
460	<code>Sigma2Process</code> and <code>Sigma3Process</code> base classes
461	in their turn derived from
462	<code><?php $filepath = $_GET["filepath"];
463	echo "<a href='SemiInternalProcesses.php?filepath=".$filepath."' target='page'>";?>SigmaProcess</a></code>.
464	This call can be used repeatedly to hand in several different processes.
465	</li>
466
467	<p/>
468	<li>
469	If your cross section contains the production of a new resonance
470	with known analytical expression for all the relevant partial widths,
471	you can make this resonance available to the program with
472	<pre>
473	pythia.setResonancePtr( resonancePtr);
474	</pre>
475	where <code>resonancePtr</code> of type <code>ResonanceWidths*</code>
476	is an instance of a class derived from the
477	<code><?php $filepath = $_GET["filepath"];
478	echo "<a href='SemiInternalResonances.php?filepath=".$filepath."' target='page'>";?>ResonanceWidths</a></code>
479	base class. In addition you need to add the particle to the normal
480	<?php $filepath = $_GET["filepath"];
481	echo "<a href='ParticleDataScheme.php?filepath=".$filepath."' target='page'>";?>particle and decay database</a>.
482	This procedure can be used repeatedly to hand in several different
483	resonances.
484	</li>
485
486	<p/>
487	<li>
488	If you are a real expert and want to <?php $filepath = $_GET["filepath"];
489	echo "<a href='ImplementNewShowers.php?filepath=".$filepath."' target='page'>";?>replace
490	the PYTHIA initial- and final-state showers</a>, you can use
491	<pre>
492	pythia.setShowerPtr( timesDecPtr, timesPtr, spacePtr);
493	</pre>
494	where <code>timesDecPtr</code> and <code>timesPtr</code>
495	derive from the <code>TimeShower</code> base class, and
496	<code>spacePtr</code> from <code>SpaceShower</code>.
497	</li>
498
499	</ol>
500
501	<p/>
502	C) Some comments on collecting several tasks in the same run.
503	<ol>
504
505	<li>
506	PYTHIA has not been written for threadsafe execution on multicore
507	processors. If you want to use all cores,
508	the most efficient way presumably is to start correspondingly many jobs,
509	with different random number seeds, and add the statistics at the end.
510	However, note that several instances can be set up in the same main
511	program, since instances are completely independent of each other,
512	so each instance could be run inside a separate thread.
513	</li>
514
515	<p/>
516	<li>
517	In some cases it is convenient to use more than one <code>Pythia</code>
518	object. The key example would be the simultaneous generation of signal
519	and pileup events, see <code>main19.cc</code>. The two objects are then
520	set up and initialized separately, and generate events completely
521	independently of each other. It is only afterwards that the event records
522	are combined into one single super-event per beam crossing.
523	</li>
524
525	<p/>
526	<li>
527	When time is not an issue, it may be that you want to perform several
528	separate subruns sequentially inside a run, e.g. to combine results for
529	several kinematical regions or to compare results for some different
530	tunes of the underlying event. One way to go is to create (and destroy)
531	one <code>pythia</code> object for each subrun, in which case they are
532	completely separate. You can also use the same <code>pythia</code> object,
533	only doing a new <code>init(...)</code> call for each subrun. In that
534	case, the settings and particle databases remain as they were in the
535	previous subrun, only affected by the specific changes you introduced in
536	the meantime. You can put those changes in the main program, with
537	<code>pythia.readString(string)</code>, using your own logic to decide
538	which ones to execute in which subrun. A corresponding possibility
539	exists with <code>pythia.readFile(fileName, subrun)</code> (or an
540	<code>istream</code> instead of a <code>fileName</code>), which as second
541	argument can take a non-negative subrun number. Then only those
542	sections of the file before any <code>Main:subrun = ...</code> line
543	or with matching <code>subrun</code> number will be read. That is, the
544	file could have a structure like
545	<pre>
546	( lines always read, i.e. "default values" always (re)set )
547	Main:subrun = 1
548	( lines only read with readFile(fileName, 1) )
549	Main:subrun = 2
550	( lines only read with readFile(fileName, 2) )
551	</pre>
552	Both of these possibilities are illustrated in <code>main08.cc</code>.
553	</li>
554
555	<p/>
556	<li>
557	When working with Les Houches Event Files, it may well be that your
558	intended input event sample is spread over several files, that you all
559	want to turn into complete events in one and the same run. There is no
560	problem with looping over several subruns, where each new subrun
561	is initialized with a new file, with name set in <code>Beams:LHEF</code>.
562	However, in that case you will do a complete re-initialization each time
563	around. If you want to avoid this, note that the flag
564	<code>Beams:newLHEFsameInit = true</code> can be set for the second and
565	subsequent subruns. Then the new file will be simulated with the same
566	initialization data as already set in a previous
567	<code>pythia.init()</code> call. The burden rests on you to ensure
568	that this is indeed correct, e.g. that the two event samples have not
569	been generated for different beam energies. Also note that cross
570	sections for processes will be based on the information in the
571	first-read file, when the full initialization is performed.
572	</li>
573
574	</ol>
575
576	<h2>The Pythia Class</h2>
577
578	Here follows the complete survey of all public <code>Pythia</code>
579	methods and data members.
580
581	<h3>Constructor and destructor</h3>
582
583	<a name="method1"></a>
584	<p/><strong>Pythia::Pythia(string xmlDir = "../xmldoc")  </strong> <br/>
585	creates an instance of the <code>Pythia</code> event generators,
586	and sets initial default values, notably for all settings and
587	particle data. You may use several <code>Pythia</code> instances
588	in the same run; only when you want to access external static
589	libraries could this cause problems. (This includes in particular
590	Fortran libraries such as <?php $filepath = $_GET["filepath"];
591	echo "<a href='PDFSelection.php?filepath=".$filepath."' target='page'>";?>LHAPDF</a>.)
592	<br/><code>argument</code><strong> xmlDir </strong> (<code>default = <strong>../xmldoc</strong></code>) : allows you to choose
593	from which directory the default settings and particle data values
594	are read in. If the <code>PYTHIA8DATA</code> environment variable
595	has been set it takes precedence. Else this optional argument allows
596	you to choose another directory location than the default one. Note
597	that it is only the directory location you can change, its contents
598	must be the ones of the <code>xmldoc</code> directory in the
599	standard distribution.
600
601
602
603	<a name="method2"></a>
604	<p/><strong>Pythia::~Pythia  </strong> <br/>
605	the destructor deletes the objects created by the constructor.
606
607	<h3>Set up run</h3>
608
609	<a name="method3"></a>
610	<p/><strong>bool Pythia::readString(string line, bool warn = true)  </strong> <br/>
611	reads in a single string, that is interpreted as an instruction to
612	modify the value of a <?php $filepath = $_GET["filepath"];
613	echo "<a href='SettingsScheme.php?filepath=".$filepath."' target='page'>";?>setting</a> or
614	<?php $filepath = $_GET["filepath"];
615	echo "<a href='ParticleDataScheme.php?filepath=".$filepath."' target='page'>";?>particle data</a>, as already described
616	above.
617	<br/><code>argument</code><strong> line </strong> :
618	the string to be interpreted as an instruction.
619
620	<br/><code>argument</code><strong> warn </strong> (<code>default = <strong>true</strong></code>) :
621	write a warning message or not whenever the instruction does not make
622	sense, e.g. if the variable does not exist in the databases.
623
624	<br/><b>Note:</b> the method returns false if it fails to
625	make sense out of the string.
626
627
628	<a name="method4"></a>
629	<p/><strong>bool Pythia::readFile(string fileName, bool warn = true, int subrun = SUBRUNDEFAULT)  </strong> <br/>
630
631	<strong>bool Pythia::readFile(string fileName, int subrun = SUBRUNDEFAULT)  </strong> <br/>
632
633	<strong>bool Pythia::readFile(istream& inStream = cin, bool warn = true, int subrun = SUBRUNDEFAULT)  </strong> <br/>
634
635	<strong>bool Pythia::readFile(istream& inStream = cin, int subrun = SUBRUNDEFAULT)  </strong> <br/>
636	reads in a whole file, where each line is interpreted as an instruction
637	to modify the value of a <?php $filepath = $_GET["filepath"];
638	echo "<a href='SettingsScheme.php?filepath=".$filepath."' target='page'>";?>setting</a> or
639	<?php $filepath = $_GET["filepath"];
640	echo "<a href='ParticleDataScheme.php?filepath=".$filepath."' target='page'>";?>particle data</a>, cf. the above
641	<code>readString</code> method. All four forms of the
642	<code>readFile</code> command share code for actually reading a file.
643	<br/><code>argument</code><strong> fileName </strong> :
644	the file from which instructions are read.
645
646	<br/><code>argument</code><strong> inStream </strong> :
647	an istream from which instructions are read.
648
649	<br/><code>argument</code><strong> warn </strong> (<code>default = <strong>true</strong></code>) :
650	write a warning message or not whenever the instruction does not make
651	sense, e.g. if the variable does not exist in the databases. In the
652	command forms where <code>warn</code> is omitted it is true.
653
654	<br/><code>argument</code><strong> subrun </strong> :
655	allows you have several optional sets of commands within the same file.
656	Only those sections of the file before any <code>Main:subrun = ...</code>
657	line or following such a line with matching subrun number will be read.
658	The subrun number should not be negative; negative codes like
659	<code>SUBRUNDEFAULT</code> corresponds to no specific subrun.
660
661	<br/><b>Note:</b> the method returns false if it fails to
662	make sense out of any one line.
663
664
665	<a name="method5"></a>
666	<p/><strong>bool Pythia::setPDFPtr( PDF* pdfAPtr, PDF* pdfBPtr, PDF* pdfHardAPtr = 0, PDF* pdfHardBPtr = 0)  </strong> <br/>
667	offers the possibility to link in external PDF sets for usage inside
668	the program. The rules for constructing your own class from
669	the <code>PDF</code> base class are described
670	<?php $filepath = $_GET["filepath"];
671	echo "<a href='PartonDistributions.php?filepath=".$filepath."' target='page'>";?>here</a>.
672	<br/><code>argument</code><strong> pdfAPtr, pdfBPtr </strong> :
673	pointers to two <code>PDF</code>-derived objects, one for each of
674	the incoming beams. The two objects have to be instantiated by you
675	in your program. Even if the two beam particles are the same
676	(protons, say) two separate instances are required, since current
677	information is cached in the objects. If both arguments are zero
678	then any previous linkage to external PDF's is disconnected,
679	see further Note 2 below.
680
681	<br/><code>argument</code><strong> pdfHardAPtr, pdfHardBPtr </strong> (<code>default = <strong>0</strong></code>) :
682	pointers to two further <code>PDF</code>-derived objects, one for each
683	of the incoming beams. Normally only the first two arguments above would
684	be used, and then the same PDF sets would be invoked everywhere. If you
685	provide these two further pointers then two different sets of PDF's are
686	used. This second set is then exclusively for the generation of the hard
687	process from the process matrix elements library. The first set above
688	is for everything else, notably parton showers and multiparton interactions.
689
690	<br/><b>Note 1:</b> The method returns false if the input is obviously
691	incorrect, e.g. if two (nonzero) pointers agree.
692	<br/><b>Note 2:</b> If you want to combine several subruns you can
693	call <code>setPDFPtr</code> with new arguments before each
694	<code>Pythia::init(...)</code> call. To revert from external PDF's
695	to the normal internal PDF selection you must call
696	<code>setPDFPtr(0, 0)</code> before <code>Pythia::init(...)</code>.
697
698
699	<a name="method6"></a>
700	<p/><strong>bool Pythia::setLHAupPtr( LHAup* lhaUpPtrIn)  </strong> <br/>
701	offers linkage to an external generator that feeds in events
702	in the LHA format, see
703	<?php $filepath = $_GET["filepath"];
704	echo "<a href='LesHouchesAccord.php?filepath=".$filepath."' target='page'>";?>Les Houches Accord</a>,
705	assuming that
706	<code><?php $filepath = $_GET["filepath"];
707	echo "<a href='BeamParameters.php?filepath=".$filepath."' target='page'>";?>Beams:frameType = 5</a></code>
708	has been set.
709	<br/><code>argument</code><strong> lhaUpPtrIn </strong> :
710	pointer to a <code>LHAup</code>-derived object.
711
712	<br/><b>Note:</b> The method currently always returns true.
713
714
715	<a name="method7"></a>
716	<p/><strong>bool Pythia::setDecayPtr( DecayHandler* decayHandlePtr, vector<int> handledParticles)  </strong> <br/>
717	offers the possibility to link to an external program that can do some
718	of the particle decays, instad of using the internal decay machinery.
719	With particles we here mean the normal hadrons and leptons, not
720	top quarks, electroweak bosons or new particles in BSM scenarios.
721	The rules for constructing your own class from the
722	<code>DecayHandler</code> base class are described
723	<?php $filepath = $_GET["filepath"];
724	echo "<a href='ExternalDecays.php?filepath=".$filepath."' target='page'>";?>here</a>. Note that you can only
725	provide one external object, but this object in its turn could
726	very well hand on different particles to separate decay libraries.
727	<br/><code>argument</code><strong> decayHandlePtr </strong> :
728	pointer to a <code>DecayHandler</code>-derived object. This object
729	must be instantiated by you in your program.
730
731	<br/><code>argument</code><strong> handledParticles </strong> : vector with the PDG identity codes
732	of the particles that should be handled by the external decay package.
733	You should only give the particle (positive) codes; the respective
734	antiparticle is always included as well.
735
736	<br/><b>Note:</b> The method currently always returns true.
737
738
739	<a name="method8"></a>
740	<p/><strong>bool Pythia::setRndmEnginePtr( RndmEngine* rndmEnginePtr)  </strong> <br/>
741	offers the possibility to link to an external random number generator.
742	The rules for constructing your own class from the
743	<code>RndmEngine</code> base class are described
744	<?php $filepath = $_GET["filepath"];
745	echo "<a href='RandomNumbers.php?filepath=".$filepath."' target='page'>";?>here</a>.
746	<br/><code>argument</code><strong> rndmEnginePtr </strong> :
747	pointer to a <code>RndmEngine</code>-derived object. This object
748	must be instantiated by you in your program.
749
750	<br/><b>Note:</b> The method returns true if the pointer is different
751	from 0.
752
753
754	<a name="method9"></a>
755	<p/><strong>bool Pythia::setUserHooksPtr( UserHooks* userHooksPtr)  </strong> <br/>
756	offers the possibility to interact with the generation process at
757	a few different specified points, e.g. to reject undesirable events
758	at an early stage to save computer time. The rules for constructing
759	your own class from the <code>UserHooks</code> base class are described
760	<?php $filepath = $_GET["filepath"];
761	echo "<a href='UserHooks.php?filepath=".$filepath."' target='page'>";?>here</a>. You can only hand in one such
762	pointer, but this may be to a class that implements several of the
763	different allowed possibilities.
764	<br/><code>argument</code><strong> userHooksPtr </strong> :
765	pointer to a <code>userHooks</code>-derived object. This object
766	must be instantiated by you in your program.
767
768	<br/><b>Note:</b> The method currently always returns true.
769
770
771	<a name="method10"></a>
772	<p/><strong>bool Pythia::setBeamShapePtr( BeamShape* beamShapePtr)  </strong> <br/>
773	offers the possibility to provide your own shape of the momentum and
774	space-time spread of the incoming beams. The rules for constructing
775	your own class from the <code>BeamShape</code> base class are described
776	<?php $filepath = $_GET["filepath"];
777	echo "<a href='BeamShape.php?filepath=".$filepath."' target='page'>";?>here</a>.
778	<br/><code>argument</code><strong> BeamShapePtr </strong> :
779	pointer to a <code>BeamShape</code>-derived object. This object
780	must be instantiated by you in your program.
781
782	<br/><b>Note:</b> The method currently always returns true.
783
784
785	<a name="method11"></a>
786	<p/><strong>bool Pythia::setSigmaPtr( SigmaProcess* sigmaPtr)  </strong> <br/>
787	offers the possibility to link your own implementation of a process
788	and its cross section, to make it a part of the normal process
789	generation machinery, without having to recompile the
790	<code>Pythia</code> library itself. The rules for constructing your
791	own class from the <code>SigmaProcess</code> base class are described
792	<?php $filepath = $_GET["filepath"];
793	echo "<a href='SemiInternalProcesses.php?filepath=".$filepath."' target='page'>";?>here</a>. You may call this
794	routine repeatedly, to add as many new processes as you wish.
795	<br/><code>argument</code><strong> sigmaPtr </strong> :
796	pointer to a <code>SigmaProcess</code>-derived object. This object
797	must be instantiated by you in your program.
798
799	<br/><b>Note:</b> The method currently always returns true.
800
801
802	<a name="method12"></a>
803	<p/><strong>bool Pythia::setResonancePtr( ResonanceWidths* resonancePtr)  </strong> <br/>
804	offers the possibility to link your own implementation of the
805	calculation of partial resonance widths, to make it a part of the
806	normal process generation machinery, without having to recompile the
807	<code>Pythia</code> library itself. This allows the decay of new
808	resonances to be handled internally, when combined with new particle
809	data. Note that the decay of normal hadrons cannot be modelled here;
810	this is for New Physics resonances. The rules for constructing your
811	own class from the <code>ResonanceWidths</code> base class are described
812	<?php $filepath = $_GET["filepath"];
813	echo "<a href='SemiInternalResonances.php?filepath=".$filepath."' target='page'>";?>here</a>. You may call this
814	routine repeatedly, to add as many new resonances as you wish.
815	<br/><code>argument</code><strong> resonancePtr </strong> :
816	pointer to a <code>ResonanceWidths</code>-derived object. This object
817	must be instantiated by you in your program.
818
819	<br/><b>Note:</b> The method currently always returns true.
820
821
822	<a name="method13"></a>
823	<p/><strong>bool Pythia::setShowerPtr( TimeShower* timesDecPtr, TimeShower* timesPtr = 0, SpaceShower* spacePtr = 0)  </strong> <br/>
824	offers the possibility to link your own parton shower routines as
825	replacements for the default ones. This is much more complicated
826	since the showers are so central and are so interlinked with other
827	parts of the program. Therefore it is also possible to do the
828	replacement in stages, from the more independent to the more
829	intertwined. The rules for constructing your own classes from the
830	<code>TimeShower</code> and <code>SpaceShower</code>base classes
831	are described <?php $filepath = $_GET["filepath"];
832	echo "<a href='ImplementNewShowers.php?filepath=".$filepath."' target='page'>";?>here</a>. These
833	objects must be instantiated by you in your program.
834	<br/><code>argument</code><strong> timesDecPtr </strong> :
835	pointer to a <code>TimeShower</code>-derived object for doing
836	timelike shower evolution in resonance decays, e.g. of a
837	<i>Z^0</i>. This is decoupled from beam remnants and parton
838	distributions, and is therefore the simplest kind of shower
839	to write. If you provide a value 0 then the internal shower
840	routine will be used.
841
842	<br/><code>argument</code><strong> timesPtr </strong> (<code>default = <strong>0</strong></code>) :
843	pointer to a <code>TimeShower</code>-derived object for doing
844	all other timelike shower evolution, which is normally interleaved
845	with multiparton interactions and spacelike showers, introducing
846	both further physics and further technical issues. If you retain
847	the default value 0 then the internal shower routine will be used.
848	You are allowed to use the same pointer as above for the
849	<code>timesDecPtr</code> if the same shower can fulfill both tasks.
850
851	<br/><code>argument</code><strong> spacePtr </strong> (<code>default = <strong>0</strong></code>) :
852	pointer to a <code>SpaceShower</code>-derived object for doing
853	all spacelike shower evolution, which is normally interleaved
854	with multiparton interactions and timelike showers. If you retain
855	the default value 0 then the internal shower routine will be used.
856
857	<br/><b>Note:</b> The method currently always returns true.
858
859
860	<h3>Initialize</h3>
861
862	At the initialization stage all the information provided above is
863	processed, and the stage is set up for the subsequent generation
864	of events. Currently several alterative forms of the <code>init</code>
865	method are available for this stage, but only the first one is
866	recommended.
867
868	<a name="method14"></a>
869	<p/><strong>bool Pythia::init()  </strong> <br/>
870	initialize for collisions, in any of the five separate possibilities
871	below. In this option the beams are not specified by input arguments,
872	but instead by the settings in the
873	<?php $filepath = $_GET["filepath"];
874	echo "<a href='BeamParameters.php?filepath=".$filepath."' target='page'>";?>Beam Parameters</a> section.
875	This allows the beams to be specified in the same file as other
876	run instructions. The default settings give pp collisions at 14 TeV.
877	<br/><b>Note:</b> The method returns false if the
878	initialization fails. It is then not possible to generate any
879	events.
880
881
882	<a name="method15"></a>
883	<p/><strong>bool Pythia::init( int idA, int idB, double eCM)  </strong> <br/>
884	initialize for collisions in the center-of-mass frame, with the
885	beams moving in the <i>+-z</i> directions.
886	<br/><code>argument</code><strong> idA, idB </strong> :
887	particle identity code for the two incoming beams.
888
889	<br/><code>argument</code><strong> eCM </strong> :
890	the CM energy of the collisions.
891
892	<br/><b>Notes:</b> Deprecated. The method returns false if the
893	initialization fails. It is then not possible to generate any
894	events.
895
896
897	<a name="method16"></a>
898	<p/><strong>bool Pythia::init( int idA, int idB, double eA, double eB)  </strong> <br/>
899	initialize for collisions with back-to-back beams,
900	moving in the <i>+-z</i> directions, but with different energies.
901	<br/><code>argument</code><strong> idA, idB </strong> :
902	particle identity code for the two incoming beams.
903
904	<br/><code>argument</code><strong> eA, eB </strong> :
905	the energies of the two beams. If an energy is set to be below
906	the mass of the respective beam particle that particle is taken to
907	be at rest. This offers a simple possibility to simulate
908	fixed-target collisions.
909
910	<br/><b>Notes:</b> Deprecated. The method returns false if the
911	initialization fails. It is then not possible to generate any
912	events.
913
914
915	<a name="method17"></a>
916	<p/><strong>bool Pythia::init( int idA, int idB, double pxA, double pyA, double pzA, double pxB, double pyB, double pzB)  </strong> <br/>
917	initialize for collisions with arbitrary beam directions.
918	<br/><code>argument</code><strong> idA, idB </strong> :
919	particle identity code for the two incoming beams.
920
921	<br/><code>argument</code><strong> pxA, pyA, pzA </strong> :
922	the three-momntum vector <i>(p_x, p_y, p_z)</i> of the first
923	incoming beam.
924
925	<br/><code>argument</code><strong> pxB, pyB, pzB </strong> :
926	the three-momntum vector <i>(p_x, p_y, p_z)</i> of the second
927	incoming beam.
928
929	<br/><b>Notes:</b> Deprecated. The method returns false if the
930	initialization fails. It is then not possible to generate any
931	events.
932
933
934	<a name="method18"></a>
935	<p/><strong>bool Pythia::init( string LesHouchesEventFile, bool skipInit = false)  </strong> <br/>
936	initialize for hard-process collisions fed in from an external file
937	with events, written according to the
938	<?php $filepath = $_GET["filepath"];
939	echo "<a href='LesHouchesAccord.php?filepath=".$filepath."' target='page'>";?>Les Houches Event File</a>
940	standard.
941	<br/><code>argument</code><strong> LesHouchesEventFile </strong> :
942	the file name (including path, where required) where the
943	events are stored, including relevant information on beam
944	identities and energies.
945
946	<br/><code>argument</code><strong> skipInit </strong> (<code>default = <strong>false</strong></code>) :
947	By default this method does a complete reinitialization of the
948	generation process. If you set this argument to true then
949	no reinitialization will occur, only the pointer to the event
950	file is updated. This may come in handy if the full event sample
951	is split across several files generated under the same conditions
952	(except random numbers, of course). You then do the first
953	initialization with the default, and all subsequent ones with
954	true. Note that things may go wrong if the files are not created
955	under the same conditions.
956
957	<br/><b>Notes:</b> Deprecated. The method returns false if the
958	initialization fails. It is then not possible to generate any
959	events.
960
961
962	<a name="method19"></a>
963	<p/><strong>bool Pythia::init( LHAup* lhaUpPtr)  </strong> <br/>
964	initialize for hard-process collisions fed in from an external
965	source of events, consistent with the Les Houches Accord standard.
966	The rules for constructing your own class from the <code>LHAup</code>
967	base class are described <?php $filepath = $_GET["filepath"];
968	echo "<a href='LesHouchesAccord.php?filepath=".$filepath."' target='page'>";?>here</a>.
969	This class is also required to provide the beam parameters.
970	<br/><code>argument</code><strong> lhaUpPtr </strong> :
971	pointer to a <code>LHAup</code>-derived object. This object
972	must be instantiated by you in your program.
973
974	<br/><b>Notes:</b> Deprecated. The method returns false if the
975	initialization fails. It is then not possible to generate any
976	events.
977
978
979	<h3>Generate events</h3>
980
981	The <code>next()</code> method is the main one to generate events.
982	In this section we also put a few other specialized methods that
983	may be useful in some circumstances.
984
985	<a name="method20"></a>
986	<p/><strong>bool Pythia::next()  </strong> <br/>
987	generate the next event. No input parameters are required; all
988	instructions have already been set up in the initialization stage.
989	<br/><b>Note:</b> The method returns false if the event generation
990	fails. The event record is then not consistent and should not be
991	studied. When reading in hard collisions from a Les Houches Event File
992	the problem may be that the end of the file has been reached. This
993	can be checked with the
994	<code><?php $filepath = $_GET["filepath"];
995	echo "<a href='EventInformation.php?filepath=".$filepath."' target='page'>";?>Info::atEndOfFile()</a></code>
996	method.
997
998
999	<a name="method21"></a>
1000	<p/><strong>int Pythia::forceTimeShower( int iBeg, int iEnd, double pTmax, int nBranchMax = 0)  </strong> <br/>
1001	perform a final-state shower evolution on partons in the
1002	<code>event</code> event record. This could be used for externally
1003	provided simple events, or even parts of events, for which
1004	a complete generation is not foreseen. Since the mother source of
1005	the parton system is not known, one cannot expect as good accuracy
1006	as in a normal generation. When two different timelike shower
1007	instances are set up, it is the one used for showering in resonance
1008	decays that is used here. The <code>forceTimeShower</code> method
1009	can be used in conjunction with the <code>forceHadronLevel</code>
1010	one below. Further comments are found
1011	<?php $filepath = $_GET["filepath"];
1012	echo "<a href='HadronLevelStandalone.php?filepath=".$filepath."' target='page'>";?>here</a>.
1013	<br/><code>argument</code><strong> iBeg, iEnd </strong> : the first and last entry of the event
1014	record to be affected by the call.
1015
1016	<br/><code>argument</code><strong> pTmax </strong> : the maximum <i>pT</i> scale of emissions.
1017	Additionally, as always, the <code>scale</code> variable of each parton
1018	sets the maximum <i>pT</i> scale of branchings of this parton.
1019	Recall that this scale defaults to 0 if not set, so that no radiation
1020	can occur.
1021
1022	<br/><code>argument</code><strong> nBranchMax </strong> (<code>default = <strong>0</strong></code>) : when positive, it sets the
1023	maximum number of branchings that are allowed to occur in the shower,
1024	i.e. the shower may stop evolving before reaching the lower cutoff.
1025	The argument has no effect when zero or negative, i.e. then the shower
1026	will continue to the lower cutoff.
1027
1028	<br/><b>Note:</b> The method returns the number of branchings that
1029	has been generated.
1030
1031
1032	<a name="method22"></a>
1033	<p/><strong>bool Pythia::forceHadronLevel(bool findJunctions = true)  </strong> <br/>
1034	hadronize the existing event record, i.e. perform string fragmentation
1035	and particle decays. There are two main applications. Firstly,
1036	you can use the same parton-level content as a basis for repeated
1037	hadronization attempts, in schemes intended to save computer time.
1038	Secondly, you may have an external program that can simulate the full
1039	partonic level of the event - hard process, parton showers, multiparton
1040	interactions, beam remnants, colour flow, and so on - but not
1041	hadronization. Further details are found
1042	<?php $filepath = $_GET["filepath"];
1043	echo "<a href='HadronLevelStandalone.php?filepath=".$filepath."' target='page'>";?>here</a>.
1044	<br/><code>argument</code><strong> findJunctions </strong> (<code>default = <strong>true</strong></code>) :
1045	normally this routine will search through the event record and try to
1046	figure out if any colour junctions are present. If so, the colour
1047	topology of such junctions must be sorted out. In tricky cases this
1048	might fail, and then hadronization will not work. A user who is
1049	aware of this and knows the intended colour flow can set up the
1050	junction information in the event record, and then call
1051	<code>forceHadronLevel(false)</code> so as not to have this information
1052	overwritten.
1053	<br/><b>Note:</b> The method returns false if the hadronization
1054	fails. The event record is then not consistent and should not be
1055	studied.
1056
1057
1058	<a name="method23"></a>
1059	<p/><strong>bool Pythia::moreDecays()  </strong> <br/>
1060	perform decays of all particles in the event record that have not been
1061	decayed but should have been done so. This can be used e.g. for
1062	repeated decay attempts, in schemes intended to save computer time.
1063	Further details are found <?php $filepath = $_GET["filepath"];
1064	echo "<a href='HadronLevelStandalone.php?filepath=".$filepath."' target='page'>";?>here</a>.
1065	<br/><b>Note:</b> The method returns false if the decays fail. The
1066	event record is then not consistent and should not be studied.
1067
1068
1069	<a name="method24"></a>
1070	<p/><strong>bool Pythia::forceRHadronDecays()  </strong> <br/>
1071	perform decays of R-hadrons that were previously considered stable.
1072	This could be if an R-hadron is sufficiently long-lived that
1073	it may interact in the detector between production and decay, so that
1074	its four-momentum is changed. Further details are found
1075	<?php $filepath = $_GET["filepath"];
1076	echo "<a href='RHadrons.php?filepath=".$filepath."' target='page'>";?>here</a>.
1077	<br/><b>Note:</b> The method returns false if the decays fail. The
1078	event record is then not consistent and should not be studied.
1079
1080
1081	<a name="method25"></a>
1082	<p/><strong>void Pythia::LHAeventList(ostream& os = cout)  </strong> <br/>
1083	list the Les Houches Accord information on the current event, see
1084	<code><?php $filepath = $_GET["filepath"];
1085	echo "<a href='LesHouchesAccord.php?filepath=".$filepath."' target='page'>";?>LHAup::listEvent(...)</a></code>.
1086	(Other listings are available via the class members below, so this
1087	listing is a special case that would not fit elsewhere.)
1088	<br/><code>argument</code><strong> os </strong> (<code>default = <strong>cout</strong></code>) :
1089	output stream where the listing occurs.
1090
1091
1092
1093	<a name="method26"></a>
1094	<p/><strong>bool Pythia::LHAeventSkip(int nSkip)  </strong> <br/>
1095	skip ahead a number of events in the Les Houches generation
1096	sequence, without doing anything further with them, see
1097	<code><?php $filepath = $_GET["filepath"];
1098	echo "<a href='LesHouchesAccord.php?filepath=".$filepath."' target='page'>";?>LHAup::skipEvent(nSkip)</a></code>.
1099	Mainly intended for debug purposes, e.g. when an event at a known
1100	location in a Les Houches Event File is causing problems.
1101	<br/><code>argument</code><strong> nSkip </strong> :
1102	number of events to skip.
1103
1104	<br/><b>Note:</b> The method returns false if the operation fails,
1105	specifically if the end of a LHEF has been reached, cf.
1106	<code>next()</code> above.
1107
1108
1109	<h3>Finalize</h3>
1110
1111	There is no required finalization step; you can stop generating events
1112	when and how you want. It is still recommended that you make it a
1113	routine to call the following method at the end. A second method provides
1114	a deprecated alternative.
1115
1116	<a name="method27"></a>
1117	<p/><strong>void Pythia::stat()  </strong> <br/>
1118	list statistics on the event generation, specifically total and partial
1119	cross sections and the number of different errors. For more details see
1120	<?php $filepath = $_GET["filepath"];
1121	echo "<a href='EventStatistics.php?filepath=".$filepath."' target='page'>";?>here</a> and for available options
1122	<?php $filepath = $_GET["filepath"];
1123	echo "<a href='MainProgramSettings.php?filepath=".$filepath."' target='page'>";?>here</a>.
1124
1125
1126	<a name="method28"></a>
1127	<p/><strong>void Pythia::statistics(bool all = false, bool reset = false)  </strong> <br/>
1128	list statistics on the event generation, specifically total and partial
1129	cross sections and the number of different errors. For more details see
1130	<?php $filepath = $_GET["filepath"];
1131	echo "<a href='EventStatistics.php?filepath=".$filepath."' target='page'>";?>here</a>.
1132	<br/><code>argument</code><strong> all </strong> (<code>default = <strong>false</strong></code>) :
1133	if true also statistics on multiparton interactions is shown, by default not.
1134
1135	<br/><code>argument</code><strong> reset </strong> (<code>default = <strong>false</strong></code>) : if true then all counters,
1136	e.g on events generated and errors experienced, are reset to zero
1137	whenever the routine is called. The default instead is that
1138	all stored statistics information is unaffected by the call. Counters
1139	are automatically reset in each new <code>Pythia::init(...)</code>
1140	call, however, so the only time the <code>reset</code> option makes a
1141	difference is if <code>statistics(...)</code> is called several times
1142	in a (sub)run.
1143
1144	<br/><b>Note:</b> Deprecated.
1145
1146
1147	<h3>Interrogate settings</h3>
1148
1149	Normally settings are used in the setup and initialization stages
1150	to determine the character of a run, e.g. read from a file with the
1151	above-described <code>Pythia::readFile(...)</code> method.
1152	There is no strict need for a user to interact with the
1153	<code>Settings</code> database in any other way. However, as an option,
1154	some settings variables have been left free for the user to set in
1155	such a file, and then use in the main program to directly affect the
1156	performance of that program, see
1157	<?php $filepath = $_GET["filepath"];
1158	echo "<a href='MainProgramSettings.php?filepath=".$filepath."' target='page'>";?>here</a>. A typical example would
1159	be the number of events to generate. For such applications the
1160	following shortcuts to some <code>Settings</code> methods may be
1161	convenient.
1162
1163	<a name="method29"></a>
1164	<p/><strong>bool Pythia::flag(string key)  </strong> <br/>
1165	read in a boolean variable from the <code>Settings</code> database.
1166	<br/><code>argument</code><strong> key </strong> :
1167	the name of the variable to be read.
1168
1169
1170
1171	<a name="method30"></a>
1172	<p/><strong>int Pythia::mode(string key)  </strong> <br/>
1173	read in an integer variable from the <code>Settings</code> database.
1174	<br/><code>argument</code><strong> key </strong> :
1175	the name of the variable to be read.
1176
1177
1178
1179	<a name="method31"></a>
1180	<p/><strong>double Pythia::parm(string key)  </strong> <br/>
1181	read in a double-precision variable from the <code>Settings</code>
1182	database.
1183	<br/><code>argument</code><strong> key </strong> :
1184	the name of the variable to be read.
1185
1186
1187
1188	<a name="method32"></a>
1189	<p/><strong>string Pythia::word(string key)  </strong> <br/>
1190	read in a string variable from the <code>Settings</code> database.
1191	<br/><code>argument</code><strong> key </strong> :
1192	the name of the variable to be read.
1193
1194
1195
1196	<h3>Data members</h3>
1197
1198	The <code>Pythia</code> class contains a few public data members,
1199	several of which play a central role. We list them here, with
1200	links to the places where they are further described.
1201
1202	<a name="method33"></a>
1203	<p/><strong>Event Pythia::process  </strong> <br/>
1204	the hard-process event record, see <?php $filepath = $_GET["filepath"];
1205	echo "<a href='EventRecord.php?filepath=".$filepath."' target='page'>";?>here</a>
1206	for further details.
1207
1208
1209	<a name="method34"></a>
1210	<p/><strong>Event Pythia::event  </strong> <br/>
1211	the complete event record, see <?php $filepath = $_GET["filepath"];
1212	echo "<a href='EventRecord.php?filepath=".$filepath."' target='page'>";?>here</a>
1213	for further details.
1214
1215
1216	<a name="method35"></a>
1217	<p/><strong>Info Pythia::info  </strong> <br/>
1218	further information on the event-generation process, see
1219	<?php $filepath = $_GET["filepath"];
1220	echo "<a href='EventInformation.php?filepath=".$filepath."' target='page'>";?>here</a> for further details.
1221
1222
1223	<a name="method36"></a>
1224	<p/><strong>Settings Pythia::settings  </strong> <br/>
1225	the settings database, see <?php $filepath = $_GET["filepath"];
1226	echo "<a href='SettingsScheme.php?filepath=".$filepath."' target='page'>";?>here</a>
1227	for further details.
1228
1229
1230	<a name="method37"></a>
1231	<p/><strong>ParticleData Pythia::particleData  </strong> <br/>
1232	the particle properties and decay tables database, see
1233	<?php $filepath = $_GET["filepath"];
1234	echo "<a href='ParticleDataScheme.php?filepath=".$filepath."' target='page'>";?>here</a> for further details.
1235
1236
1237	<a name="method38"></a>
1238	<p/><strong>Rndm Pythia::rndm  </strong> <br/>
1239	the random number generator, see <?php $filepath = $_GET["filepath"];
1240	echo "<a href='RandomNumberSeed.php?filepath=".$filepath."' target='page'>";?>here</a>
1241	and <?php $filepath = $_GET["filepath"];
1242	echo "<a href='RandomNumbers.php?filepath=".$filepath."' target='page'>";?>here</a> for further details.
1243
1244
1245	<a name="method39"></a>
1246	<p/><strong>CoupSM Pythia::coupSM  </strong> <br/>
1247	Standard Model couplings and mixing matrices, see
1248	<?php $filepath = $_GET["filepath"];
1249	echo "<a href='StandardModelParameters.php?filepath=".$filepath."' target='page'>";?>here</a> for further details.
1250
1251
1252	<a name="method40"></a>
1253	<p/><strong>SusyLesHouches Pythia::slha  </strong> <br/>
1254	parameters and particle data in the context of supersymmetric models,
1255	see <?php $filepath = $_GET["filepath"];
1256	echo "<a href='SUSYLesHouchesAccord.php?filepath=".$filepath."' target='page'>";?>here</a> for further details.
1257
1258
1259	<a name="method41"></a>
1260	<p/><strong>PartonSystems Pythia::partonSystems  </strong> <br/>
1261	a grouping of the partons in the event record by subsystem,
1262	see <?php $filepath = $_GET["filepath"];
1263	echo "<a href='AdvancedUsage.php?filepath=".$filepath."' target='page'>";?>here</a> for further details.
1264
1265
1266	</body>
1267	</html>
1268
1269	<!-- Copyright (C) 2012 Torbjorn Sjostrand -->

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