Particle Tracing

[f0uriest]

Adds functionality for tracing particles in an arbitrary MagneticField, using either guiding center or full orbit equations.

[github-actions]

|             benchmark_name             |         dt(%)          |         dt(s)          |        t_new(s)        |        t_old(s)        | 
| -------------------------------------- | ---------------------- | ---------------------- | ---------------------- | ---------------------- |
 test_build_transform_fft_lowres         |     -6.87 +/- 5.59     | -1.39e-03 +/- 1.13e-03 |  1.89e-02 +/- 1.3e-04  |  2.03e-02 +/- 1.1e-03  |
 test_build_transform_fft_midres         |     -0.07 +/- 1.05     | -7.41e-05 +/- 1.17e-03 |  1.11e-01 +/- 5.0e-04  |  1.11e-01 +/- 1.1e-03  |
 test_build_transform_fft_highres        |     -0.23 +/- 1.35     | -1.16e-03 +/- 6.99e-03 |  5.15e-01 +/- 3.3e-03  |  5.16e-01 +/- 6.2e-03  |
 test_equilibrium_init_lowres            |     -1.72 +/- 2.08     | -1.47e-02 +/- 1.78e-02 |  8.44e-01 +/- 1.4e-02  |  8.59e-01 +/- 1.1e-02  |
 test_equilibrium_init_medres            |     -1.55 +/- 1.40     | -1.98e-02 +/- 1.78e-02 |  1.26e+00 +/- 9.8e-03  |  1.27e+00 +/- 1.5e-02  |
 test_equilibrium_init_highres           |     -0.21 +/- 0.83     | -6.46e-03 +/- 2.50e-02 |  3.02e+00 +/- 1.8e-02  |  3.02e+00 +/- 1.7e-02  |
 test_objective_compile_dshape_current   |     -1.98 +/- 6.82     | -1.07e-01 +/- 3.68e-01 |  5.29e+00 +/- 2.9e-01  |  5.39e+00 +/- 2.2e-01  |
 test_objective_compile_atf              |     -0.95 +/- 5.84     | -1.63e-01 +/- 1.00e+00 |  1.70e+01 +/- 7.2e-01  |  1.72e+01 +/- 7.0e-01  |
 test_objective_compute_dshape_current   |     -1.08 +/- 1.06     | -3.60e-05 +/- 3.53e-05 |  3.31e-03 +/- 2.6e-05  |  3.34e-03 +/- 2.4e-05  |
 test_objective_compute_atf              |     -2.37 +/- 0.94     | -2.64e-04 +/- 1.05e-04 |  1.09e-02 +/- 4.3e-05  |  1.12e-02 +/- 9.6e-05  |
 test_objective_jac_dshape_current       |     -2.31 +/- 6.58     | -3.29e-03 +/- 9.36e-03 |  1.39e-01 +/- 5.2e-03  |  1.42e-01 +/- 7.8e-03  |
 test_objective_jac_atf                  |     -8.23 +/- 5.80     | -7.19e-01 +/- 5.06e-01 |  8.02e+00 +/- 5.0e-01  |  8.74e+00 +/- 8.0e-02  |
 test_perturb_1                          |     -1.04 +/- 12.62    | -1.14e-01 +/- 1.38e+00 |  1.08e+01 +/- 9.2e-01  |  1.09e+01 +/- 1.0e+00  |
 test_perturb_2                          |     -1.59 +/- 5.14     | -3.01e-01 +/- 9.70e-01 |  1.86e+01 +/- 6.0e-01  |  1.89e+01 +/- 7.6e-01  |

[github-actions]

|             benchmark_name             |         dt(%)          |         dt(s)          |        t_new(s)        |        t_old(s)        | 
| -------------------------------------- | ---------------------- | ---------------------- | ---------------------- | ---------------------- |
 test_build_transform_fft_lowres         |     +1.25 +/- 1.62     | +1.56e-04 +/- 2.02e-04 |  1.26e-02 +/- 1.9e-04  |  1.25e-02 +/- 8.1e-05  |
 test_build_transform_fft_midres         |     -0.01 +/- 1.23     | -1.19e-05 +/- 1.13e-03 |  9.24e-02 +/- 7.0e-04  |  9.24e-02 +/- 9.0e-04  |
 test_build_transform_fft_highres        |     +1.21 +/- 0.72     | +5.62e-03 +/- 3.32e-03 |  4.69e-01 +/- 1.9e-03  |  4.63e-01 +/- 2.7e-03  |
 test_equilibrium_init_lowres            |     +2.70 +/- 1.62     | +2.13e-02 +/- 1.28e-02 |  8.12e-01 +/- 1.1e-02  |  7.91e-01 +/- 6.3e-03  |
 test_equilibrium_init_medres            |     +1.58 +/- 1.37     | +2.23e-02 +/- 1.94e-02 |  1.43e+00 +/- 1.5e-02  |  1.41e+00 +/- 1.3e-02  |
 test_equilibrium_init_highres           |     +0.61 +/- 1.32     | +2.54e-02 +/- 5.51e-02 |  4.21e+00 +/- 4.5e-02  |  4.18e+00 +/- 3.1e-02  |
 test_objective_compile_dshape_current   |     +1.16 +/- 9.78     | +4.73e-02 +/- 3.98e-01 |  4.12e+00 +/- 3.3e-01  |  4.07e+00 +/- 2.3e-01  |
 test_objective_compile_atf              |     -3.85 +/- 5.66     | -3.63e-01 +/- 5.34e-01 |  9.07e+00 +/- 3.2e-01  |  9.43e+00 +/- 4.3e-01  |
 test_objective_compute_dshape_current   |     -0.85 +/- 1.95     | -1.84e-05 +/- 4.25e-05 |  2.16e-03 +/- 2.7e-05  |  2.18e-03 +/- 3.3e-05  |
 test_objective_compute_atf              |     +1.72 +/- 1.21     | +1.30e-04 +/- 9.13e-05 |  7.70e-03 +/- 6.1e-05  |  7.57e-03 +/- 6.8e-05  |
 test_objective_jac_dshape_current       |     -3.41 +/- 12.79    | -1.61e-03 +/- 6.03e-03 |  4.55e-02 +/- 3.8e-03  |  4.71e-02 +/- 4.7e-03  |
 test_objective_jac_atf                  |     -3.18 +/- 6.69     | -7.55e-02 +/- 1.59e-01 |  2.30e+00 +/- 7.4e-02  |  2.37e+00 +/- 1.4e-01  |
 test_perturb_1                          |     -0.78 +/- 13.58    | -6.56e-02 +/- 1.14e+00 |  8.31e+00 +/- 7.7e-01  |  8.37e+00 +/- 8.4e-01  |
 test_perturb_2                          |     -5.08 +/- 5.34     | -7.50e-01 +/- 7.88e-01 |  1.40e+01 +/- 5.5e-01  |  1.48e+01 +/- 5.7e-01  |

[codecov]

Codecov Report

Attention: Patch coverage is 25.66372% with 84 lines in your changes missing coverage. Please review.

Project coverage is 95.11%. Comparing base (acc8e5a) to head (b2156d5).

Files with missing lines	Patch %	Lines
desc/magnetic_fields/_core.py	25.66%	84 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #734      +/-   ##
==========================================
- Coverage   95.44%   95.11%   -0.33%     
==========================================
  Files          95       95              
  Lines       23402    23503     +101     
==========================================
+ Hits        22336    22356      +20     
- Misses       1066     1147      +81     

Files with missing lines	Coverage Δ
desc/magnetic_fields/_core.py	87.78% <25.66%> (-8.79%)	⬇️

... and 2 files with indirect coverage changes

[github-actions]

|             benchmark_name             |         dt(%)          |         dt(s)          |        t_new(s)        |        t_old(s)        | 
| -------------------------------------- | ---------------------- | ---------------------- | ---------------------- | ---------------------- |
 test_build_transform_fft_lowres         |     +0.00 +/- 3.04     | +2.27e-05 +/- 1.58e-02 |  5.19e-01 +/- 1.2e-02  |  5.19e-01 +/- 9.7e-03  |
 test_equilibrium_init_medres            |     +1.08 +/- 0.95     | +4.41e-02 +/- 3.87e-02 |  4.11e+00 +/- 2.7e-02  |  4.06e+00 +/- 2.7e-02  |
 test_equilibrium_init_highres           |     +0.67 +/- 0.84     | +3.65e-02 +/- 4.55e-02 |  5.45e+00 +/- 3.0e-02  |  5.42e+00 +/- 3.4e-02  |
 test_objective_compile_dshape_current   |     +0.62 +/- 1.14     | +2.36e-02 +/- 4.34e-02 |  3.84e+00 +/- 3.2e-02  |  3.81e+00 +/- 3.0e-02  |
 test_objective_compute_dshape_current   |     +0.35 +/- 1.93     | +1.21e-05 +/- 6.64e-05 |  3.46e-03 +/- 4.5e-05  |  3.45e-03 +/- 4.9e-05  |
 test_objective_jac_dshape_current       |     +1.39 +/- 4.45     | +5.64e-04 +/- 1.80e-03 |  4.10e-02 +/- 1.0e-03  |  4.04e-02 +/- 1.5e-03  |
 test_perturb_2                          |     +0.09 +/- 0.70     | +1.62e-02 +/- 1.20e-01 |  1.72e+01 +/- 7.0e-02  |  1.72e+01 +/- 9.8e-02  |
 test_proximal_freeb_jac                 |     -0.51 +/- 1.50     | -3.82e-02 +/- 1.13e-01 |  7.47e+00 +/- 9.4e-02  |  7.51e+00 +/- 6.3e-02  |
 test_solve_fixed_iter                   |     -1.37 +/- 59.79    | -7.04e-02 +/- 3.07e+00 |  5.06e+00 +/- 2.2e+00  |  5.13e+00 +/- 2.1e+00  |

[YigitElma]

If you want to get rid of some PRs, I can take this one. It looks interesting and I am bored:D

[f0uriest]

If you want to get rid of some PRs, I can take this one. It looks interesting and I am bored:D

Sure, main thing it needs is some tests, so probably just need to come up with some simple magnetic fields for which we know the trajectory analytically and make sure they agree. Some ideas:

• Uniform B (using VerticalField) to test basic motion (guiding center should move in straight line, full orbit should be a helix)
• B with gradient (MagneticFieldFromUser with B = B0*x or something, to test grad B drift
• Purely toroidal field to test gradB and curvature drift

[rahulgaur104]

Do you have a symplectic orbit solver to compare with? I have one that I can add to the test.
It calculates the the exact particle position instead of just guiding center. We only have to run it once, gyroaverage and save the data.

[f0uriest]

Do you have a symplectic orbit solver to compare with? I have one that I can add to the test. It calculates the the exact particle position instead of just guiding center. We only have to run it once, gyroaverage and save the data.

Yeah I benchmarked against SIMPLE with rogerio, I'll try to dig up the data