====== Frequently asked questions ======

===== General =====

==== More details ====

** More information **

For more information, refer to the [[documentation:manual|user manual]].






===== Modeling ===== 




==== Random seed ====

** Random seed **

  * Mersenne Twister from C\+\+ compiler (gcc version > 4.6) or Boost library when available.
  * ''Time'' -> ''RandomSeed'' 

** Reproducibility ** 

  * In simulation using multithreading (openMP), each thread gets its own random seed. Therefore, to reproduce exact results, one needs to specify the same random seed as well as the same number of threads. 


==== Spatial scale ====

** Lattice scale **

  * ''Space -> NodeLength''

This affects the diffusion coefficient in ''PDE'' models.

Dimensionless space is assumed, unless a unit is specified.




===== Analysis ===== 



==== Data output and visualization ====

** Logger **

//Note: this plugin will be restructured in the near future.//

The ''Logger'' periodically writes the values of the symbols specified in the ''Format'' to file.

Its ''Plot'' function can generate timeplots, or phase plots, depending on the ''columns'' selected for the axes. Note: these columns correspond to the column number in the generated data file (first column = 1).

** HistogramLogger **

''HistogramLogger'' calculates frequency distributions and writes them to file.

Its ''Plot'' function can generate timeplots.


==== Parameter sweep / Batch processing ====

To explore the effect of a parameter on model behavior, you can set up a batch process called ''ParamSweep''. \\

** 1. Select parameters ** 

In the ''Attributes'' window, press right-click on a parameter and choose ''ParamSweep''. A 'fast-forward' symbol appear indicating that this parameter is set for a parameter sweep.

Alternatively, if no ''Attributes'' windows is available (e.g. with ''Expression''), right-click in the central window to select for ''ParamSweep''. 
 
Note that model parameters of any type can be explored (''double, int, string, enum,'' etc.).

[{{ :faq_paramsweep1.png?direct&400 | Right-click in ''Attributes'' window to select parameter for ''ParamSweep''}}]

** 2. Set range of values **

Once you have chosen a parameter, go to the ''ParamSweep'' view (see ''Documents'' window).

Here, you can specify a range of values for each parameter.

^ Syntax ^ Example ^ Generated sequence ^ Description ^
| **value1;value2;value3** | 1.0;1.25;4 | 1.0;1.25;4 | Sequence of values | 
| **string1;string2;string3** | "square";"hexagonal" | "square";"hexagonal" | Sequence of strings | 
| **min:increment:max** | 0:2:10 | 0;2;4;6;8;10 | Range of values with increment |
| **min:#steps:max** | 0:#2:10 | 0;5;10 | Range of values with number of steps | 
| **min:#steps[log]:max** | 0.1:#2log:10 | 0.1;1.0;10.0 | Range of values with number of steps in logarithmic scale | 

The ''Number of Jobs'' that will be generated is calculated and displayed.

[{{ :faq_paramsweep2.png?direct&600 | Specify range of values in ''ParamSweep'' window and execute batch process by pressing ''Start''.}}]

** 3. Execute ''ParamSweep'' **

To start a parameter sweep, **press ''Start'' in the toolbar** while you have the ''ParamSweep'' panel open.

Before it starts the batch process, Morpheus let's you check your jobs and parameters in a pop-up window.

Also note that batch processes can benefit from **parallel computing** by allowing multiple concurrent jobs, see ''Settings -> Local -> Concurrent Jobs''.

Note that the parameter sweep is always run in ''Local'' mode (overrides ''Interactive'' mode).

** Multi-dimensional ''ParamSweeps'' ** 

Multi-dimensional parameter sweep are generated by selecting multiple parameters for ''ParamSweep''. 

To couple multiple parameters such that they are incremented simultaneously, drag one over the other to 'pair' them.  

** How to post-process results of a parameter sweep? ** 

Morpheus does not include tools for post-processing of data. Thus, analyzing results should be done using your own favorite tools.

Yet, Morpheus does supply a few features that enable you to analyze results of parameter sweeps:

  * Sweep summary: file containing data on parameters and the folder in which the results are saved. 
  * Python scripts:
    * morphMakeTable.py: generate $Latex$ table from images from a parameter sweep (using sweep summary)
    * morphSweepData.py: gather data from log files from a parameter sweep (using sweep summary)

** ImageTable **

This option can be used to create a $Latex$ table of images from a parameter sweep. This is a simplified interface to the python script morphMakeTable.py.

[{{ :faq_paramsweep3.png?direct&600 |}}]

===== Editing ===== 

==== Add or remove model items ====

** Add/Remove in Document view **

To add or remove optional model components such as ''PDE'', ''CellTypes'', or ''CellPopulation'', right-click in the Documents View and choose ''Add'' or ''Remove''.
 
[{{ :faq_addmodel.png?direct&300 |Right-click in the Documents view}}]

** Add/Remove in Editor view **

To add or remove optional plugins, right-click **on the parent node** and choose ''Add'' or ''Remove''. The parent node is the place on which the new plugin should appear.

In case of ''Remove'', you will be prompted to confirm the removal.

[{{ :faq_addmodel2.png?direct&300 |Right-click on parent node in editor view}}]

** Save to Clipboard **

To remove but save a copy on the ''Clipboard'', choose ''Cut''. You will not be prompted for confirmation. \\

==== Copy/paste items ====

** Copy **

To **copy** an item, right-click in the editor view and choose **''Copy''**. The XML snippet will be shown in the ''Clipboard''.

** Paste **

To **paste** an item that appears on the ''Clipboard'', right-click in the editor view **on the parent item** and choose **''Paste''**. Choose an item from the **drop-down list**. 

Note that you can copy/paste between different models.

An extract of the XML will be shown as a **tooltip**. This enables you to distinguish items with identical names.

** Clipboard **

Snippets of XML that were copied or cut are shown here. The Clipboard is shared over all models in the Documents view.

[{{ :faq_copypaste.png?direct&500 | }}]

** Copy/Paste between models **

During model construction, it is often useful to copy/paste items between different models that appear in the Documents view. For instance, to integrate single-scale models into a multi-scale model. \\

This is possible, because the Clipboard is shared over all models in the Documents view.

==== Disable items ====

** Disable **

During the model construction or testing process, it is often desirable to temporarily **switch off an item** of the model without removing it from the model.

To **switch off** an item, right-click in the editor view and choose **''Disable''**. A 'pause' symbol appears before the node, and the item as well as its child nodes are grayed out.

Note that the item is still saved to XML, but is commented out.

** Re-enable **

To re-enable, do the same: right-click in the editor view and choose **''Disable''**.

[{{ :faq_disable.png?direct&300 | Switch off a model item by right-click and choose ''Disable''.}}]


==== Edit XML model without GUI ====

** Text editor **

The XML files can be opened in any text editor that allow you to manually edit the model.

** Command line tools **

More advanced editing of the XML files requires command line tools like [[http://xmlstar.sourceforge.net/overview.php|xmlstarlet]]. 

For example, to remove all ''Property'' items from the ''CellType'' called ''ct1'', do:
<code>
xmlstarlet ed -d "/MorpheusModel/CellTypes/CellType[@name='ct1']/Property" model_old.xml > model_new.xml
</code>

=====  GUI ===== 


==== FixBoard ====

** FixBoard **

When you open a outdated or broken XML model, Morpheus will try to automagically correct and update the model. For example, Morpheus creates required elements that are missing and removes obsolete elements.

The changes that Morpheus made are shown on the ''Fixboard''. **You are strongly advised to review those changes**.

As an example, the following message will appear in the ''FixBoard'' when we invalidate the [[examples:miscellaneous#Minimal model|minimal model]] by removing the ''Description'', ''Space'' and ''Time'' elements and replace them with an fictitious ''FakeNode'' node:

<code xml>
 <?xml version='1.0' encoding='UTF-8'?>
 <MorpheusModel version="1">
    <FakeNode/>
 </MorpheusModel>
</code>

[{{ :documentation:fixboard.png?direct&300 |The ''FixBoard'' shows the automatic changes make in a broken or outdated model for review.}}]

Note that this is a feature of graphical user interface. The command line interface ''morpheus'' cannot correct outdated or broken models supplied as command line arguments. 

==== JobQueue (job archive) ====

** JobQueue **

This panel has multiple functions:
  * Overview of pending, running and terminated jobs
  * Archive of simulation models 
  * Sorting simulation jobs and sweeps
  * Access to simulation result browser
  * Stop and remove jobs and results

==== Result browser ====

** Morpheus results browser ** 

Simulation results can be shown by clicking the job in the ''JobQueue''. This opens a file browser within Morpheus showing the ''Output Folder'' and the ''Output Text''.

** File browser and terminal ** 

The buttons above the result browser can be used to open the ''Output Folder'' your system-wide file browser or open in a ''Terminal''.

[{{ :faq_directory1.png?direct&300 |Use the buttons to open ''Output Folder'' in your file browser or in ''terminal''.}}]

** Change results folder **

To change the folder where results are stored, check the Settings.

[{{ :faq_directory.png?direct&400 |The folder where results are stored can be changed in ''File->Settings''.}}]

** Reset ''JobQueue'' archive **

The information in the ''JobQueue'' is stored in using a SQLite database. This database is named ''morpheus.db.sqlite'' and stored in the OS-specific folder for Application Data. 

Remove or rename the file ''morpheus.db.sqlite'' to reset the job archive. Note that this does not remove the simulation results themselves.