Program Flow Sample
Learn how to control the flow of your program by using loops (aka repetition. For example, the following loops count from 1 to 10, printing the numbers as.
Program Flow Program Flow Recall that, to first order, the event generation process can be subdivided into three stages: • Initializaion. • The event loop. This is reflected in how the top-level Pythia class should be used in the user-supplied main program, further outlined in the following. Since the nature of the run is defined at the initialization stage, this is where most of the PYTHIA user code has to be written. So as not to confuse the reader unduly, the description of initialization options has been subdivided into what would normally be used and what is intended for more special applications. At the bottom of this webpage is a complete survey of all public Pythia methods and data members, in a more formal style than the task-oriented descriptions found in the preceding sections.
This offers complementary information. Initialization - normal usage • Already at the top of the main program file, you need to include the proper header file #include 'Pythia8/Pythia.h' To simplify typing, it also makes sense to declare using namespace Pythia8; • The first step is to create a generator object, e.g. With Pythia pythia; It is this object that we will use from now on.
What made it stand out what that it separated its skill improvement from normal experience gain. Grandia video game.
Normally a run will only contain one Pythia object. (But you can use several Pythia objects, which then will be independent of each other.) By default all output from Pythia will be on the cout stream, but the list methods below do allow output to alternative streams or files. • You next want to set up the character of the run. The pages under the 'Setup Run Tasks' heading in the index describe all the options available (with some very few exceptions, found on the other pages).
The default values and your modifications are stored in two databases, one for and one for. Both of these are initialized with their default values by the Pythia constructor.
Debut Program Flow
The default values can then be changed, primarily by one of the two ways below, or by a combination of them. A) You can use the pythia.readString(string); method repeatedly to do a change of a property at a time. The information in the string is case-insensitive, but upper- and lowercase can be combined for clarity.
Program Flowchart Examples
The rules are that (i) if the first nonblank character of the string is a letter it is assumed to contain a setting, and is sent on to pythia.settings.readString(string); (ii) if instead the string begins with a digit it is assumed to contain particle data updates, and so sent on to pythia.particleData.readString(string); (iii) if none of the above, the string is assumed to be a comment, i.e. Nothing will be done. In the former two cases, a warning is issued whenever a string cannot be recognized (maybe because of a spelling mistake). Some examples would be pythia.readString('TimeShower:pTmin = 1.0'); pythia.readString('111:mayDecay = false'); The readString(string) method is intended primarily for a few changes. It can also be useful if you want to construct a parser for input files that contain commands both to PYTHIA and to other libraries. B) You can read in a file containing a list of those variables you want to see changed, with a pythia.readFile(fileName); Each line in this file with be processes by the readString(string) method introduced above.
You can thus freely mix comment lines and lines handed on to Settings or to ParticleData. This approach is better suited for more extensive changes than a direct usage of readString(string), and can also avoid having to recompile and relink your main program between runs. It is also possible to read input from an istream, by default cin, rather than from a file. This may be convenient if information is generated on-the-fly, within the same run.