adjusted and extended the two problems

docs/exercise1.rst

@@ -15,18 +15,18 @@ For example, if you decide to use YAML::
     
   cp ../../problems/1_control_flow/*.yaml .
 
-One by one, check the three sequential workflows **f1_pitstop_seq_wrong_1.yaml**, 
-**f1_pitstop_seq_wrong_2.yaml**, and **f1_pitstop_seq_wrong_3.yaml** for errors, 
-and then find and correct the errors.
+Then, for each sequential workflow (**f1_pitstop_seq_wrong_1.yaml**,
+**f1_pitstop_seq_wrong_2.yaml**, and **f1_pitstop_seq_wrong_3.yaml**) carry out
+the following steps:
 
-Add the workflow to the LaunchPad and query its state.
-
-Execute the workflow with the command::
-
-  rlaunch singleshot
-
-i.e. run one Firework at a time. After running every Firework, monitor the
-output and the states of the Fireworks until the workflow is completed.
+* Inspect the workflow for errors and correct the errors
+* Add the workflow to the LaunchPad checking again for errors
+* Create a workflow graph and make sure it is correct; delete the workflow if
+  necessary, correct it in the workflow file and add it again to launchpad
+* Query the workflow state
+* Execute the workflow in *singleshot* mode, i.e. run one Firework at a time.
+  After running every Firework, monitor the output and the states of the Fireworks
+  until the workflow is completed.
 
 
 Problem 1.2
@@ -34,4 +34,13 @@ Problem 1.2
 
 Repeat the steps of **Problem 1.1** for the parallel version of the workflow:
 **f1_pitstop_par_wrong_1.json**, **f1_pitstop_par_wrong_2.json** and 
-**f1_pitstop_par_wrong_3.json**.
+**f1_pitstop_par_wrong_3.json**. Try different modes to launch the workflows:
+
+* ``rlaunch singleshot``: launch one firework from launchpad
+* ``rlaunch rapidfire``: launch many fireworks in a sequence
+* ``rlaunch multi <N>``: launch N fireworks in parallel, choose N from [2, 3, 4]
+
+Add the flag *--help* to each of the launch modes to see all available options.
+For the multi mode, try to find N and the parameters nlaunches, sleep and timeout
+for which the best speedup can be achieved using the command::
+  time rlaunch multi <N> --nlaunches <L> --sleep <sec> --timeout <sec>
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