Binary source combined with xallarap

[rpoleski]

Task to be done to have a model with binary source and their full orbital motion (BSPL_xallarap branch):

• make sure .n_sources for xallarap models depends on whether q_source is defined or not
• second source trajectory - shift by 180 in xi_u and change xi_semimajor_axis
• ModelParameters._update_sources() - update and add calls to it
• source mass ratio in ModelParameters
• limit source mass ratio to > 0.
• ModelParameters.source_2_parameters
• make sure q_source cannot be mixed with, e.g., t_0_X
• Currently the xallarap parameters of each source are not obtained directly (like, e.g., t_0_1) - do we want that? xi_a_2 is problematic. After discussion with @jenniferyee : No. We should give proper documentation only.
• tests for FS case - code changed in commit 053a760
• Model.get_trajectory() (see also issue #94)
• check all calls to Trajectory()
• ModelParameters.xallarap_reference_position - define it in a standard way (including docstring)
• ModelParameters.xallarap_reference_position - unit tests
• print xallarap reference position while printing ModelParameters
• properly print q_source
• test Model.plot_trajectory()
• test that printing parameters of both sources separately gives the same reference position
• proper error message for mm.ModelParameters({'t_0': 1, 'u_0': 2, 't_E': 3, 'q_source': 1})
• proper error message for xallarap parameters with rho_2 but without q_soruce
• parameter_names.pdf
• coverage of added code - modelparameters.py line 327
• flake8, version number, sphinx, README.md

After merge:

• Example 16 - add new parameters to _set_default_parameters() and _check_fixed_parameters()

[rpoleski]

@jenniferyee What should be the parameter name for source mass-ratio? Possibilities I can think about:

1. q_source
2. q_xi
3. xi_q
4. something else?

[jenniferyee]

I think q_source. -------------------------------------------------------------- Dr. Jennifer C. Yee (she/her) Office: P-341 Center for Astrophysics | Harvard & Smithsonian 60 Garden St, MS-15 Cambridge, MA 02138 --------------------------------------------------------------

…

On Mon, Jul 24, 2023 at 11:38 AM Radek Poleski ***@***.***> wrote: @jenniferyee <https://github.com/jenniferyee> What should be the parameter name for source mass-ratio? Possibilities I can think about: 1. q_source 2. q_xi 3. xi_q 4. something else? — Reply to this email directly, view it on GitHub <#92 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AEK7UCO55UGFNXPFIMGMVB3XR2JFRANCNFSM6AAAAAA2VYQPRQ> . You are receiving this because you were mentioned.Message ID: ***@***.***>

[rpoleski]

Notes for myself on Trajectory:

• FitData.get_dataset_trajectory - called twice in that file for gradient calculation; that function should be written more consistently
• MagnificationCurve.trajectory - called only in that file; is MagnificationCurve only for a single source?
• Model.get_trajectory - called only in FitData.get_dataset_trajectory listed above