comparison-with-ode-solver.md

-Two body elliptical orbit, comparing SWIFT with scipy ODE solver.
+Test particle in circular orbit around a solar mass particle, radius of 3AU
 
-![orbit_plot_20](/uploads/62d35c0436cb5b43c2027ed9a535a58a/orbit_plot_20.png)
+Compare SWIFT solution with analytic solution, and the solution from the scipy ODE solver with 10^6 timesteps per orbit.
 
-Tried to calculate error by finding difference between positions at the time of the snapshots, but it doesn't look like I'm doing this correctly.
+Show the effect of decreasing 'eta'.
 
-![orbit_plot_32](/uploads/a14f30f66e6acf65d59cc710a86fa4a4/orbit_plot_32.png)
+![point_mass_eta_test_r_3_m_1](/uploads/2b591b4a16225c7280d5c62b2ea1ce18/point_mass_eta_test_r_3_m_1.png)
 
-![orbit_plot_31](/uploads/16a56da37484e6ee948880f2cdfc075b/orbit_plot_31.png)
+Now solve a similiar problem but replace the central particle with a line of 10 particles, from -0.5 AU to 0.5 AU along the x-axis, with total mass of one solar mass. Initial position and velocity of the orbiting test particle is still the same.
 
-Did the same thing with an orbit around a line of ten particles.
+Can test the effect of changing both the multipole order and 'eta'
 
-![orbit_plot_8](/uploads/2a5b83143021633f4a581fda80d4d185/orbit_plot_8.png)
+![particle_line_m_order_test_r_3_minus_log_10_eta_3](/uploads/bad8f189532a5580bfb2e32a1dbb2de4/particle_line_m_order_test_r_3_minus_log_10_eta_3.png)
 
-![orbit_plot_7](/uploads/f7103a6ad6de7192931a996a29f47290/orbit_plot_7.png)
+![particle_line_eta_test_r_3_m_1](/uploads/b2d8b5907a9cd20b468bc5201d9f579b/particle_line_eta_test_r_3_m_1.png)
 
-![orbit_plot_34](/uploads/46365ffff4b3d3737a13bfe2b4a1af6d/orbit_plot_34.png)
+Now do the same this again but with a triangle of particles, centred on [0.5,0.5,0.5], evenly spaced around a circle of radius 0.3 AU in the x-y plane, this was done to ensure the particles were all in the same cell.
 
-![orbit_plot_35](/uploads/a9c0d3f7b411700541342205b7fb3ec9/orbit_plot_35.png)
 
-![orbit_plot_36](/uploads/1c9829643d948b40fcbf06ef50706856/orbit_plot_36.png)
+![triangle_m_order_test_r_3_minus_log_eta_2](/uploads/4d0fd4bc1626189966e54f2db29a0251/triangle_m_order_test_r_3_minus_log_eta_2.png)
 
+![triangle_eta_test_r_3_m_1](/uploads/a53b775fd0b6e7ff38f7e5f0474023d5/triangle_eta_test_r_3_m_1.png)