1 | <chapter name="Error Checks"> |
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2 | |
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3 | <h2>Error Checks</h2> |
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4 | |
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5 | There is a few settings related to error checking during program |
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6 | execution. Many other checks are performed as well, but do not |
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7 | have any specific setting related to themselves. |
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8 | |
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9 | <flag name="Check:abortIfVeto" default="off"> |
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10 | There are a few ways in which an event can be vetoed, the most |
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11 | common being a <aloc href="UserHooks">User Hooks</aloc> test. |
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12 | Normally this will simply mean that the next parton-level |
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13 | configuration is selected inside the <code>Pythia::next()</code> |
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14 | routine, without any need for a user intervention. With this |
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15 | option switched on, however, <code>Pythia::next()</code> will |
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16 | return <code>false</code>. It is then up to the user to decide |
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17 | what to do next. |
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18 | </flag> |
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19 | |
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20 | <flag name="Check:particleData" default="off"> |
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21 | Check the particle data tables for potential problems during |
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22 | initialization. This includes inconsistent use of charge in particle |
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23 | names, inconsistent setup of mass, mass range, width and lifetime, |
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24 | sum of branching ratios not unity (allowed but discouraged) or charge |
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25 | not conserved in a decay channel. Warnings should be viewed as reasons |
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26 | to check further, but need not indicate a true problem, and also not all |
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27 | problems may be caught. |
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28 | The <code>pythia.particleData.checkTable(level)</code> method, |
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29 | used for these checks, may also be called directly. |
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30 | </flag> |
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31 | |
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32 | <modepick name="Check:levelParticleData" default="1"> |
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33 | The level of verbosity and checks of particle data, if switched on. |
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34 | <option value="0">mimimal amount of checks, e.g. that no channels open. |
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35 | </option> |
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36 | <option value="1">further warning if individual channels closed, |
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37 | except for resonances.</option> |
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38 | <option value="2">also print branching-ratio-averaged threshold mass |
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39 | except for resonances.</option> |
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40 | <option value="11">as 1, but include resonances in detailed checks. |
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41 | </option> |
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42 | <option value="12">as 2, but include resonances in detailed checks. |
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43 | </option> |
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44 | </modepick> |
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45 | |
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46 | <flag name="Check:event" default="on"> |
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47 | When an event has been successfully generated, check that the |
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48 | final event record in <code>event</code> does not contain any |
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49 | unphysical particles, or nonconserved charge or energy-momentum. |
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50 | If this check fails, then <code>pythia.next()</code> obtains the |
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51 | value <code>false</code>, i.e. the event is counted as aborted. |
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52 | </flag> |
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53 | |
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54 | <flag name="Check:history" default="on"> |
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55 | When <code>Check:event = on</code> and the event is checked as above, |
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56 | further checks are made that all mother and daughter pointers are |
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57 | consistently set. Specifically that all daughters in the |
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58 | <code>daughterlist</code> (or <code>motherList</code>) have the |
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59 | particle in their respective <code>motherList</code> |
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60 | (or <code>daughterlist</code>). This operation takes a bit more |
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61 | time than the other error tests (of the order of 10% of what it takes |
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62 | to generate the event in the first place), and so could be switched off |
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63 | to save time. |
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64 | </flag> |
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65 | |
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66 | |
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67 | <modeopen name="Check:nErrList" default="0"> |
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68 | The number of erroneous events, in the above check, for which |
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69 | event listing and other detailed information will be printed. |
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70 | After that, only the normal error messages will be issued. |
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71 | Error counters are always updated, and accumulated numbers can be |
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72 | shown with <code>pythia.statistics()</code> at the end of the run. |
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73 | </modeopen> |
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74 | |
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75 | <parm name="Check:epTolErr" default="1e-4"> |
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76 | Maximum allowed summed deviation of <ei>E</ei>, <ei>p_x</ei>, |
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77 | <ei>p_y</ei> and <ei>p_z</ei> between the incoming beams and the |
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78 | final state, as a fraction of the initial energy, above which the |
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79 | event is counted as aborted. |
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80 | (Unfortunetely roundoff errors do not scale linearly with the energy, |
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81 | and also have a very long tail. So while most events at lower energies |
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82 | may be correct to better than 1e-10, at LHC it does not have to signal |
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83 | any fundamental bug if also the default tolerance above is violated |
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84 | occasionally.) |
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85 | </parm> |
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86 | |
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87 | <parm name="Check:epTolWarn" default="1e-6"> |
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88 | A check on the same summed deviation as above, but counted as a |
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89 | warning rather than an error, and not leading to the event being |
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90 | classified as aborted. |
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91 | </parm> |
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92 | |
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93 | </chapter> |
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94 | |
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95 | <!-- Copyright (C) 2012 Torbjorn Sjostrand --> |
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