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# Tutorial: Running populations with binary_c-python
# Tutorial: Running populations with binary_c-python
This notebook will show you how to evolve a population of stars
This notebook will show you how to evolve a population of stars
Much of the code in the binarycpython package is written to evolve a population of stars through the Population object, rather than running a single system. Let's go through the functionality of this object step by step and set up some example populations.
Much of the code in the binarycpython package is written to evolve a population of stars through the Population object, rather than running a single system. Let's go through the functionality of this object step by step and set up some example populations.
At the bottom of this notebook there are some complete example scripts
At the bottom of this notebook there are some complete example scripts
To set up and configure the population object we need to make an object instance of the `Population` object, and add configuration via the `.set()` function.
To set up and configure the population object we need to make an object instance of the `Population` object, and add configuration via the `.set()` function.
There are three categories of options that the Population object can set:
There are three categories of options that the Population object can set:
- BSE options: these options will be used for the binary_c calls, and are recognized by comparing the arguments to a known list of available arguments of binary_c. To see which options are available, see section [`binary_c parameters` in the documentation](https://ri0005.pages.surrey.ac.uk/binary_c-python/binary_c_parameters.html). You can access these through `population.bse_options['<bse option name>']` after you have set them.
- BSE options: these options will be used for the binary_c calls, and are recognized by comparing the arguments to a known list of available arguments of binary_c. To see which options are available, see section [`binary_c parameters` in the documentation](https://ri0005.pages.surrey.ac.uk/binary_c-python/binary_c_parameters.html). You can access these through `population.bse_options['<bse option name>']` after you have set them.
- Grid options: these options will be used to configure the behaviour of the Population object. To see which options are available, see section [`Population grid code options` in the documentation](https://ri0005.pages.surrey.ac.uk/binary_c-python/grid_options_descriptions.html). They can be accessed via `population.grid_options['<grid option name>']` after you have set them.
- Grid options: these options will be used to configure the behaviour of the Population object. To see which options are available, see section [`Population grid code options` in the documentation](https://ri0005.pages.surrey.ac.uk/binary_c-python/grid_options_descriptions.html). They can be accessed via `population.grid_options['<grid option name>']` after you have set them.
- Custom options: these options are not recognized as either of the above, so they will be stored in the custom_options, and can be accessed via `population.custom_options['<custom option name>']`
- Custom options: these options are not recognized as either of the above, so they will be stored in the custom_options, and can be accessed via `population.custom_options['<custom option name>']`
adding: tmp_dir=/tmp/binary_c_python-david/notebooks/notebook_population to grid_options
adding: tmp_dir=/tmp/binary_c_python-david/notebooks/notebook_population to grid_options
<<<< Warning: Key does not match previously known parameter: adding: data_dir=/tmp/binary_c_python-david/notebooks/notebook_population/example_python_population_result to custom_options >>>>
<<<< Warning: Key does not match previously known parameter: adding: data_dir=/tmp/binary_c_python-david/notebooks/notebook_population/example_python_population_result to custom_options >>>>
<<<< Warning: Key does not match previously known parameter: adding: base_filename=example_pop.dat to custom_options >>>>
<<<< Warning: Key does not match previously known parameter: adding: base_filename=example_pop.dat to custom_options >>>>
After configuring the population, but before running the actual population, its usually a good idea to export the full configuration (including version info of binary_c and all the parameters) to a file. To do this we use `example_pop.export_all_info()`.
After configuring the population, but before running the actual population, its usually a good idea to export the full configuration (including version info of binary_c and all the parameters) to a file. To do this we use `example_pop.export_all_info()`.
On default this exports everything, each of the sections can be disabled:
On default this exports everything, each of the sections can be disabled:
- population settings (bse_options, grid_options, custom_options), turn off with include_population
- population settings (bse_options, grid_options, custom_options), turn off with include_population
settings=False
settings=False
- binary_c_defaults (all the commandline arguments that binary c accepts, and their defaults).
- binary_c_defaults (all the commandline arguments that binary c accepts, and their defaults).
turn off with include_binary_c_defaults=False
turn off with include_binary_c_defaults=False
- include_binary_c_version_info (all the compilation info, and information about the compiled
- include_binary_c_version_info (all the compilation info, and information about the compiled
parameters), turn off with include_binary_c_version_info=False
parameters), turn off with include_binary_c_version_info=False
- include_binary_c_help_all (all the help information for all the binary_c parameters),
- include_binary_c_help_all (all the help information for all the binary_c parameters),
turn off with include_binary_c_help_all=Fase
turn off with include_binary_c_help_all=Fase
On default it will write this to the custom_options['data_dir'], but that can be overriden by setting use_datadir=False and providing an outfile=<>
On default it will write this to the custom_options['data_dir'], but that can be overriden by setting use_datadir=False and providing an outfile=<>
post-lock: <Lock /tmp/binary_c_python-david/notebooks/notebook_population/example_python_population_result/example_pop_settings.json.gz.lock [unlocked: 0:00:15] pid=147908 at 0x7f5278ecd970x>
post-lock: <Lock /tmp/binary_c_python-david/notebooks/notebook_population/example_python_population_result/example_pop_settings.json.gz.lock [unlocked: 0:00:15] pid=147908 at 0x7f5278ecd970x>
try to lock <Lock /tmp/binary_c_python-david/notebooks/notebook_population/example_python_population_result/example_pop_settings.json.gz.lock [unlocked: 0:01:00] pid=147908 at 0x7f5278ecd970x>
try to lock <Lock /tmp/binary_c_python-david/notebooks/notebook_population/example_python_population_result/example_pop_settings.json.gz.lock [unlocked: 0:01:00] pid=147908 at 0x7f5278ecd970x>
locked <Lock /tmp/binary_c_python-david/notebooks/notebook_population/example_python_population_result/example_pop_settings.json.gz.lock [locked: 0:01:00] pid=147908 at 0x7f5278ecd970x>
locked <Lock /tmp/binary_c_python-david/notebooks/notebook_population/example_python_population_result/example_pop_settings.json.gz.lock [locked: 0:01:00] pid=147908 at 0x7f5278ecd970x>
/tmp/binary_c_python-david/notebooks/notebook_population/example_python_population_result/example_pop_settings.json.gz is locked by <Lock /tmp/binary_c_python-david/notebooks/notebook_population/example_python_population_result/example_pop_settings.json.gz.lock [locked: 0:01:00] pid=147908 at 0x7f5278ecd970x> to /tmp/binary_c_python-david/notebooks/notebook_population/example_python_population_result/example_pop_settings.json.gz.lock
/tmp/binary_c_python-david/notebooks/notebook_population/example_python_population_result/example_pop_settings.json.gz is locked by <Lock /tmp/binary_c_python-david/notebooks/notebook_population/example_python_population_result/example_pop_settings.json.gz.lock [locked: 0:01:00] pid=147908 at 0x7f5278ecd970x> to /tmp/binary_c_python-david/notebooks/notebook_population/example_python_population_result/example_pop_settings.json.gz.lock
Try to open file at /tmp/binary_c_python-david/notebooks/notebook_population/example_python_population_result/example_pop_settings.json.gz
Try to open file at /tmp/binary_c_python-david/notebooks/notebook_population/example_python_population_result/example_pop_settings.json.gz
The main purpose of the Population object is to handle the population synthesis side of running a set of stars. The main method to do this with binarycpython, as is the case with Perl binarygrid, is to use grid variables. These are loops over a predefined range of values, where a probability will be assigned to the systems based on the chosen probability distributions.
The main purpose of the Population object is to handle the population synthesis side of running a set of stars. The main method to do this with binarycpython, as is the case with Perl binarygrid, is to use grid variables. These are loops over a predefined range of values, where a probability will be assigned to the systems based on the chosen probability distributions.
Usually we use either 1 mass grid variable, or a trio of mass, mass ratio and period (See below for full examples of all of these). We can, however, also add grid sampling for e.g. eccentricity, metallicity or other parameters.
Usually we use either 1 mass grid variable, or a trio of mass, mass ratio and period (See below for full examples of all of these). We can, however, also add grid sampling for e.g. eccentricity, metallicity or other parameters.
In some cases it could be easier to set up a for loop that sets that parameter and calls the evolve function several times, e.g. when you want to vary a prescription (usually a discrete, unweighted parameter)
In some cases it could be easier to set up a for loop that sets that parameter and calls the evolve function several times, e.g. when you want to vary a prescription (usually a discrete, unweighted parameter)
A notable special type of grid variable is that of the Moe & di Stefano 2017 dataset (see further down in the notebook).
A notable special type of grid variable is that of the Moe & di Stefano 2017 dataset (see further down in the notebook).
To add a grid variable to the population object we use `example_pop.add_grid_variable` (see next cell)
To add a grid variable to the population object we use `example_pop.add_grid_variable` (see next cell)
All the distribution functions that we can use are stored in the `binarycpython.utils.distribution_functions` or `binarycpython/utils/distribution_functions.py` on git. If you uncomment the help statement below you can see which functions are available now:
All the distribution functions that we can use are stored in the `binarycpython.utils.distribution_functions` or `binarycpython/utils/distribution_functions.py` on git. If you uncomment the help statement below you can see which functions are available now:
The next cell contains an example of adding the mass grid variable, but sampling in log mass. The commented grid variables are examples of the mass ratio sampling and the period sampling.
The next cell contains an example of adding the mass grid variable, but sampling in log mass. The commented grid variables are examples of the mass ratio sampling and the period sampling.
On default, binary_c will not output anything (except for 'SINGLE STAR LIFETIME'). It is up to us to determine what will be printed. We can either do that by hardcoding the print statements into `binary_c` (see documentation binary_c). Or, we can use the custom logging functionality of binarycpython (see notebook `notebook_custom_logging.ipynb`), which is faster to set up and requires no recompilation of binary_c, but is somewhat more limited in its functionality.
On default, binary_c will not output anything (except for 'SINGLE STAR LIFETIME'). It is up to us to determine what will be printed. We can either do that by hardcoding the print statements into `binary_c` (see documentation binary_c). Or, we can use the custom logging functionality of binarycpython (see notebook `notebook_custom_logging.ipynb`), which is faster to set up and requires no recompilation of binary_c, but is somewhat more limited in its functionality.
After configuring what will be printed, we need to make a function to parse the output. This can be done by setting the parse_function parameter in the population object (see also notebook `notebook_individual_systems.ipynb`).
After configuring what will be printed, we need to make a function to parse the output. This can be done by setting the parse_function parameter in the population object (see also notebook `notebook_individual_systems.ipynb`).
In the code below we will set up both the custom logging, and a parse function to handle that output
In the code below we will set up both the custom logging, and a parse function to handle that output
Now that we configured all the main parts of the population object, we can actually run the population! Doing this is straightforward: `example_pop.evolve()`
Now that we configured all the main parts of the population object, we can actually run the population! Doing this is straightforward: `example_pop.evolve()`
This will start up the processing of all the systems. We can control how many cores are used by settings `num_cores`. By setting the `verbosity` of the population object to a higher value we can get a lot of verbose information about the run, but for now we will set it to 0.
This will start up the processing of all the systems. We can control how many cores are used by settings `num_cores`. By setting the `verbosity` of the population object to a higher value we can get a lot of verbose information about the run, but for now we will set it to 0.
There are many grid_options that can lead to different behaviour of the evolution of the grid. Please do have a look at those: [grid options docs](https://ri0005.pages.surrey.ac.uk/binary_c-python/grid_options_descriptions.html), and try
There are many grid_options that can lead to different behaviour of the evolution of the grid. Please do have a look at those: [grid options docs](https://ri0005.pages.surrey.ac.uk/binary_c-python/grid_options_descriptions.html), and try
After the run is complete, some technical report on the run is returned. I stored that in `analytics`. As we can see below, this dictionary is like a status report of the evolution. Useful for e.g. debugging.
After the run is complete, some technical report on the run is returned. I stored that in `analytics`. As we can see below, this dictionary is like a status report of the evolution. Useful for e.g. debugging.
<<<< Warning: Key does not match previously known parameter: adding: data_dir=/tmp/binary_c_python-david/notebooks/notebook_population/example_python_population_result to custom_options >>>>
<<<< Warning: Key does not match previously known parameter: adding: data_dir=/tmp/binary_c_python-david/notebooks/notebook_population/example_python_population_result to custom_options >>>>
<<<< Warning: Key does not match previously known parameter: adding: base_filename=example_pop.dat to custom_options >>>>
<<<< Warning: Key does not match previously known parameter: adding: base_filename=example_pop.dat to custom_options >>>>
ok
ok
File at /tmp/binary_c_python-david/notebooks/notebook_population/example_python_population_result/example_pop_settings.json.gz already exists: cannot write to it
File at /tmp/binary_c_python-david/notebooks/notebook_population/example_python_population_result/example_pop_settings.json.gz already exists: cannot write to it
ok
ok
Do dry run? True
Do dry run? True
Doing dry run to calculate total starcount and probability
Doing dry run to calculate total starcount and probability
Grid has handled 19 stars with a total probability of 0.0443872
Grid has handled 19 stars with a total probability of 0.0443872
We can also set up a population that samples binary systems, by adding extra grid variables. Below is an example of a full script that runs a binary population and registers when a double compact object is formed. The logging is rather compact and should be expanded to be more useful. Also note that we run very little systems in the following example, as its just intended to show how the code works.
We can also set up a population that samples binary systems, by adding extra grid variables. Below is an example of a full script that runs a binary population and registers when a double compact object is formed. The logging is rather compact and should be expanded to be more useful. Also note that we run very little systems in the following example, as its just intended to show how the code works.
