Changeset 750cff for src/documentation/constructs/observers_observables.dox

Timestamp:

Oct 31, 2011, 5:13:52 PM (14 years ago)

Author:

Frederik Heber <heber@…>

Branches:

Action_Thermostats, Add_AtomRandomPerturbation, Add_FitFragmentPartialChargesAction, Add_RotateAroundBondAction, Add_SelectAtomByNameAction, Added_ParseSaveFragmentResults, AddingActions_SaveParseParticleParameters, Adding_Graph_to_ChangeBondActions, Adding_MD_integration_tests, Adding_ParticleName_to_Atom, Adding_StructOpt_integration_tests, AtomFragments, Automaking_mpqc_open, AutomationFragmentation_failures, Candidate_v1.5.4, Candidate_v1.6.0, Candidate_v1.6.1, Candidate_v1.7.0, ChangeBugEmailaddress, ChangingTestPorts, ChemicalSpaceEvaluator, CombiningParticlePotentialParsing, Combining_Subpackages, Debian_Package_split, Debian_package_split_molecuildergui_only, Disabling_MemDebug, Docu_Python_wait, EmpiricalPotential_contain_HomologyGraph, EmpiricalPotential_contain_HomologyGraph_documentation, Enable_parallel_make_install, Enhance_userguide, Enhanced_StructuralOptimization, Enhanced_StructuralOptimization_continued, Example_ManyWaysToTranslateAtom, Exclude_Hydrogens_annealWithBondGraph, FitPartialCharges_GlobalError, Fix_BoundInBox_CenterInBox_MoleculeActions, Fix_ChargeSampling_PBC, Fix_ChronosMutex, Fix_FitPartialCharges, Fix_FitPotential_needs_atomicnumbers, Fix_ForceAnnealing, Fix_IndependentFragmentGrids, Fix_ParseParticles, Fix_ParseParticles_split_forward_backward_Actions, Fix_PopActions, Fix_QtFragmentList_sorted_selection, Fix_Restrictedkeyset_FragmentMolecule, Fix_StatusMsg, Fix_StepWorldTime_single_argument, Fix_Verbose_Codepatterns, Fix_fitting_potentials, Fixes, ForceAnnealing_goodresults, ForceAnnealing_oldresults, ForceAnnealing_tocheck, ForceAnnealing_with_BondGraph, ForceAnnealing_with_BondGraph_continued, ForceAnnealing_with_BondGraph_continued_betteresults, ForceAnnealing_with_BondGraph_contraction-expansion, FragmentAction_writes_AtomFragments, FragmentMolecule_checks_bonddegrees, GeometryObjects, Gui_Fixes, Gui_displays_atomic_force_velocity, ImplicitCharges, IndependentFragmentGrids, IndependentFragmentGrids_IndividualZeroInstances, IndependentFragmentGrids_IntegrationTest, IndependentFragmentGrids_Sole_NN_Calculation, JobMarket_RobustOnKillsSegFaults, JobMarket_StableWorkerPool, JobMarket_unresolvable_hostname_fix, MoreRobust_FragmentAutomation, ODR_violation_mpqc_open, PartialCharges_OrthogonalSummation, PdbParser_setsAtomName, PythonUI_with_named_parameters, QtGui_reactivate_TimeChanged_changes, Recreated_GuiChecks, Rewrite_FitPartialCharges, RotateToPrincipalAxisSystem_UndoRedo, SaturateAtoms_findBestMatching, SaturateAtoms_singleDegree, StoppableMakroAction, Subpackage_CodePatterns, Subpackage_JobMarket, Subpackage_LinearAlgebra, Subpackage_levmar, Subpackage_mpqc_open, Subpackage_vmg, Switchable_LogView, ThirdParty_MPQC_rebuilt_buildsystem, TrajectoryDependenant_MaxOrder, TremoloParser_IncreasedPrecision, TremoloParser_MultipleTimesteps, TremoloParser_setsAtomName, Ubuntu_1604_changes, stable

Children:

5982c5

Parents:

19bc74

Message:

HUGE: Update on documenation.

• a general skeleton of the documentation is now in place with all the major components of MoleCuilder explained to some extent.
• some information has been transfered from TRAC (e.g. install procecure) into this doxygen documentation where it is general and not specific to the situation at our institute.

File:

• src/documentation/constructs/observers_observables.dox (modified) (1 diff)

src/documentation/constructs/observers_observables.dox

@@ -12 +12 @@
  *    Author: heber
  */
+
+/** \page observers Observers and Observables
+ *
+ * The Observer/Observerable mechanism is crucial to let different and
+ * independent components know about changes among one another. E.g. when an
+ * the element of an atom changes, the GUI (\ref graphical) needs to know
+ * about this change to plot the atom with a different color or shape.
+ *
+ * The Observer/Observerable mechanism is basically just a call-back: A
+ * class announces itself as Observable with having a specific interface
+ * of functions. Observer may signOn() to this class and have a specific
+ * function (update()) be called whenever a change occurs in the Observable
+ * class.
+ *
+ * Note that additionally an Observable may have various \a channels and
+ * Observers may signOn() to just such a channel to get a very specific
+ * update. E.g. a LinkedCell class needs to know when the position of an
+ * atom changes but it does not need to know about changes of element or
+ * velocity, ... These updates are called \a Notifications.
+ *
+ * As an example:
+ * \code
+ * World::getInstance().signOn(this, World::getInstance().getChannel(World::AtomInserted));
+ * \endcode
+ * Here, in the constructor of GLWorldView the class signs on to atoms
+ * being inserted into the World such that it can add these onto the display
+ * as well. Notifications are received via recieveNotifications(), e.g.
+ * which you have to implement for an Observer class
+ * \code
+ *   switch (notification->getChannelNo()) {
+ *   case World::AtomInserted:
+ *   {
+ *     const atom *_atom = World::getInstance().lastChanged<atom>();
+ *     emit atomInserted(_atom);
+ *     break;
+ *   }
+ * \endcode
+ * Here, we just switch over all events that we process and care about (note
+ * that we only get called for those for which we have subscribed) and proceed.
+ *
+ * \note There is a complete logging mechanism available for this. However,
+ * it has to be compiled via a specific switch (\ref install). So, when
+ * you need to know why your function isn't notified, that's the way to
+ * find out.
+ *
+ * Be wary of where the update occurs: while the World tells you about new
+ * or destroyed atoms, only the atom itself tells you when its position has
+ * changed!
+ *
+ * \section observers-world Observers and the World
+ *
+ * The World, containing the arrays of all atoms and molecules, is a bit
+ * special with these observers. E.g. when you request a non-const array
+ * of atoms you receive an ObservedIterator. That is one where automatically
+ * it is assumed that you changed something and hence update() is called
+ * after you stepped over one of its elements.
+ *
+ * Thus, use const-iterators and arrays whenever possible, first to avoid
+ * this overhead, but second to avoid making pain-in-the-ass, hard-to-find
+ * mistakes.
+ *
+ * Also, the world stores specific information about what changed in the
+ * template function World::lastChanged() where it might contain reference
+ * to an atom that is about to be destroyed or just added.
+ *
+ *
+ * \date 2011-10-31
+ *
+ */