Timeline for Simple n-body class in C++
Current License: CC BY-SA 4.0
11 events
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| Oct 25, 2019 at 20:38 | comment | added | G. Sliepen |
You could use std::valarray<> as @Davislor suggested, but that lacks more interesting functions, like calculating the length of a vector. Math libraries will do that for you.
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| Oct 25, 2019 at 20:32 | comment | added | Gilfoyle |
Can I also use std::array<double, DIM> instead of a vector math library as you suggested? Could I then also get rid of the for loop?
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| Oct 25, 2019 at 19:52 | comment | added | G. Sliepen | Yes, that's correct. | |
| Oct 25, 2019 at 19:05 | comment | added | Gilfoyle |
Am I correct in assuming that I then have to use void Particle::force(Particle& other) and inside force() I remove all i-> and replace j-> by other->?
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| Oct 25, 2019 at 18:28 | comment | added | G. Sliepen |
Once you've written void force(Particle &other) as a member function of struct Particle, change force(&p[i], &p[j]) to p[i].force(p[j]) inside the nested loop. Here you should probably keep using int i and int j as iterator variables, as that's the easiest to ensure each pair is only visited once.
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| Oct 25, 2019 at 16:24 | comment | added | Gilfoyle | Can you please outline how you would compute the force with your approach? I have difficulties since I have in the case of the force computation a nested loop and I am not sure how to do that in this case. | |
| Oct 25, 2019 at 16:14 | comment | added | G. Sliepen |
I recommend you use auto whenever the type is already clear from the context, or when you don't care about the type. Here, it should be obvious that p is a Particle, because it's an element of particles. Using auto in these cases avoids repeating types unnecessarily, and potentially avoids mistakes.
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| Oct 25, 2019 at 15:36 | comment | added | Gilfoyle |
Is it recommended to use for (auto &p: particles) or is for (Particle &p: particles) better? When should I not use auto?
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| Oct 25, 2019 at 7:51 | comment | added | Gilfoyle |
I tried to incorporate first the second part of your answer but get the following errors: nbody.cpp: In member function ‘void Particle::update_position(double)’: nbody.cpp:47:33: error: ‘p’ was not declared in this scope const double a = dt * 0.5 / p->m; ^ nbody.cpp: In member function ‘void Nbody::comp_position()’: nbody.cpp:55:19: error: ‘particles’ was not declared in this scope for (auto &p: particles) {
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| Oct 24, 2019 at 19:42 | history | edited | G. Sliepen | CC BY-SA 4.0 |
added 872 characters in body
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| Oct 24, 2019 at 19:28 | history | answered | G. Sliepen | CC BY-SA 4.0 |