multi config analysis

[sahiljhawar]

The aim of this PR is to allow multiple model/configuration analysis with the use config/yaml file, follows from #214, #215 and b4fd564. However there are several pitfalls when using MPI:

• With or without mpiexec the injection.log for the first configuration is populated by all the logs. And no log files are created for subsequent analysis.
• With mpiexec, while individual configurations are running parallely but the multiple configurations are executed sequentially. To solve this, this PR is created.
• In an attempt to solve the above issue, a --parallel flag is introduced which upon using distributes the given number of processess (specified using mpiexec -np) amongst all the configurations and try to execute them in parallel. However this does not seem to work. Here are two differnent cases now.
  • Firstly, if comm.Barrier() and MPI.Finalize() are used then the program gets stuck with file not found errors (for the 2nd configuration)
  • If these are not used then the analysis of first configuration is completed and the execution terminates.
• Even when --parallel is not used (but mpiexec is), the beaviour is somewhat erratic; analysis of first configuration is completed and gets stuck while executing the later.

For now I would recommended not to use yaml file for multiple configuration analysis, since it might break somewhere in between.

Use the given commands to duplicate the issues:

• mpiexec -np 10 light_curve_analysis --config config.yaml
• mpiexec -np 10 light_curve_analysis --config config.yaml --parallel
• uncommenting comm.Barrier() and MPI.Finalize() and again mpiexec -np 10 light_curve_analysis --config config.yaml --parallel

I would like everyone who knows MPI (possibly much more than me) to have a look on this.
Also, DO NOT MERGE :')

[mcoughlin]

@tsunhopang Any chance you can help @sahiljhawar ?

[sahiljhawar]

Continued in #230