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/*! @page deployment Deploy the simulation

@tableofcontents

Once you've specified your @ref platform "virtual platform" and the
@ref application "application" you want to study, you must describe
the mapping of the application onto the platform. This page says how
to do that if you go for online simulation (that is, the study of a
program), you must say which code starts on which host, with which
parameters. You can also go for offline simulation, i.e. the study of
a trace captured from a past applicative run, as briefly explained
@ref XBT_replay "here".

There is two ways to specify the mapping of your program onto virtual
hosts: either directly from your program (with @ref MSG_process_create
or as in @ref s4u_ex_basics "this S4U example"), or using an external
XML file.  You should really logically separate your application from
the deployment, as it will ease your experimental campain afterward.
How exactly you organize your work remains up to you.

@section deploy_s4u Deployment with S4U

The following example shows the several ways of doing so in the S4U
interface: @ref examples/s4u/actor-create/s4u_actor-create.cpp.
Associated XML file: @ref examples/s4u/actor-create/s4u_actor-create_d.xml

@section deploy_msg Deployment with MSG

If you're stuck with the MSG interface, then you should simply use one
of the following functions to start new actors onto your virtual
hosts: @ref MSG_process_create, @ref MSG_process_create_with_arguments
or @ref MSG_process_create_with_environment. These functions are used
in many of the provided example, just grep for them.

@section deploy_xml Deployment with XML

Deploying actors from XML is easy. This section presents a complete
example and the reference guide of the involved tags.

The deployment file looks just like a @ref platform "platform" file,
with only 3 tags used:

  - @c <actor> starts a new actor on a given host;
  - @c <argument> passes a given argument in the argv of an actor
    (the list of arguments is ordered);
  - @c <prop> adds a property to the actor.

@subsection deploy_xml_ex Examples

To make them easy to find, almost all deployment files in the archive
are named @c ***_d_xml.

@verbatim
<?xml version='1.0'?>
<!DOCTYPE platform SYSTEM "http://simgrid.gforge.inria.fr/simgrid/simgrid.dtd">
<platform version="4">
  <!-- Alice, which runs on the machine named 'host1', does not take any parameter -->
  <actor host="host1" function="alice" />

  <!-- Bob, which runs on 'host2', has 2 parameters "3" and "3000" in its argv -->
  <actor host="host2" function="bob" />
     <argument value="3"/>
     <argument value="3000"/>
  </actor>

  <!-- Carole runs on 'host3', has 1 parameter "42" in its argv and one property -->
  <!-- See MSG_process_get_property_value() to retrieve this property -->
  <actor host="host3" function="carole">
      <argument value="42"/>
      <prop id="SomeProp" value="SomeValue"/>
  </actor>
</platform>
@endverbatim

@subsection deploy_xml_actor The actor tag

&lt;actor&gt; starts a new actor on a given host. It specifies which
function (from your application) gets executed on the host. Hence, the
@c host and @c function attributes are mandatory, but this tag accepts
some optional attributes too.

| Attribute name  | Mandatory | Values       | Description                                                                     |
| --------------- | --------- | ------------ | -----------                                                                     |
| host            | yes       | String       | This must match the name of an host defined in the platform file.               |
| function        | yes       | String       | Name of the function (from your own code) that will be executed.  See @ref deploy_xml_functions. |
| start_time      | no        | int          | The simulated time when this actor will be started (Default: ASAP).             |
| kill_time       | no        | int          | The simulated time when this actor will be forcefully stopped (Default: never). |
| on_failure      | no        | DIE\|RESTART | What should be done when the actor fails (Default: die).       |

@subsection deploy_xml_argument The argument tag

This tag (which must be enclosed in a @c &lt;actor&gt; tag) adds a
new string to the parameter list received by your actor (either its @c
argv array in MSG or its @c args vector in S4U).  Naturally, the
semantic of these parameters completely depend on your program.

| Attribute name  | Mandatory | Values                 | Description             |
| --------------- | --------- | ---------------------- | -----------             |
| value           | yes       | String                 | Value of this parameter |

@subsection deploy_xml_prop The prop tag

This tag (which must be enclosed in a @c &lt;actor&gt; tag) adds a new
property to your actor. You can retrieve these properties with
MSG_process_get_property_value() or simgrid::s4u::Actor::property().
Naturally, the semantic of these parameters completely depend on your
program.

| Attribute name  | Mandatory | Values                 | Description                  |
| --------------- | --------- | ---------------------- | -----------                  |
| id              | yes       | String                 | Name of the defined property |
| value           | yes       | String                 | Value of this property       |

@subsection deploy_xml_functions Declaring startable functions

You need to connect your code to the names that you use in the XML
deployment file. Depending on the interface you use, this is done with
MSG_process_create() or simgrid::s4u::Engine::registerFunction().
There is nothing to do in your **Java code** since SimGrid uses
the Java introspection abilities to retrieve the classes from their
names. In your XML file, you must then use the full class name
(including the package name).

*/