(#220) Updated doc service-101 for HTCondor

doc/service_guide_101/htcondor.md

@@ -6,7 +6,7 @@ Creating a HTCondor compute service                        {#guide-101-htcondor}
 # Overview #            {#guide-htcondor-overview}
 
 [HTCondor](http://htcondor.org) is a workload management framework that supervises 
-task executions on local and remote resources.
+task executions on various sets of resources.
 HTCondor is composed of six main service daemons (`startd`, `starter`, 
 `schedd`, `shadow`, `negotiator`, and `collector`). In addition, 
 each host on which one or more of these daemons is spawned must also 
@@ -23,40 +23,44 @@ compute service (`wrench::ComputeService`), which is defined by the
 service requires the following parameters:
 
 - The name of a host on which to start the service;
-- The HTCondor pool name;
-- A `std::set` of `wrench::ComputeService` available to the HTCondor pool; and
+- A `std::set` of 'child' `wrench::ComputeService` instances available to the HTCondor pool; and
 - A `std::map` of properties (`wrench::HTCondorComputeServiceProperty`) and message 
   payloads (`wrench::HTCondorComputeServiceMessagePayload`).
 
-The set of compute services may represent any computing instance natively 
-provided by WRENCH (e.g., bare-metal servers, cloud platforms, batch-scheduled
-clusters, etc.) or additional services derived from the `wrench::ComputeService`
-base class. The example below creates an instance of an HTCondor service
+The set of compute services may include compute service instances that are either
+`wrench::BareMetalComputeService` or `wrench::BatchComputeService` instances.
+The example below creates an instance of an HTCondor service
 with a pool of resources containing a [Bare-metal](@ref guide-baremetal) server:
 
 ~~~~~~~~~~~~~{.cpp}
 // Simulation 
 wrench::Simulation simulation;
 simulation.init(&argc, argv);
 
-// Create bare-metal service
-std::set<wrench::ComputeService *> compute_services;
-compute_services.insert(new wrench::BareMetalComputeService(
+// Create a bare-metal service
+
+auto baremetal_service = simulation.add(
+    new wrench::BareMetalComputeService(
           "execution_hostname",
           {std::make_pair(
                   "execution_hostname",
                   std::make_tuple(wrench::Simulation::getHostNumCores("execution_hostname"),
                                   wrench::Simulation::getHostMemoryCapacity("execution_hostname")))},
           "/scratch/"));
 
-auto compute_service = simulation->add(
+std::set<std::shared_ptr<wrench::ComputeService>> compute_services;
+compute_services.insert(baremetal_service);
+
+auto htcondor_compute_service = simulation->add(
           new wrench::HTCondorComputeService(hostname, 
-                                      "local", 
                                       std::move(compute_services),
                                       {{wrench::HTCondorComputeServiceProperty::SUPPORTS_PILOT_JOBS, "false"}}
                                       ));
 ~~~~~~~~~~~~~
 
+Jobs submitted to the `wrench::HTCondorComputeService` instance will be dispatched to one
+of the 'child' compute services available to that instance (only one in the above example). 
+
 
 # Anatomy of the HTCondor Service #        {#guide-htcondor-anatomy}