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spin:esc202_fs2020 [2020/03/16 07:28]
stadel [Lectures]
spin:esc202_fs2020 [2020/05/04 08:12] (current)
stadel [List of assignments]
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 Joachim Stadel Joachim Stadel
 ---- ----
 +===== Video Lectures =====
 +
 +Videos for the lectures can be found here (they are too large for my Wiki):
 +
 +[[http://​www.ics.uzh.ch/​~stadel/​krone/​public_downloads/​esc202|ESC202 Video downloads]]
 +
  
 ====== Lectures ====== ====== Lectures ======
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 2. Mar. 2020: {{ :​spin:​sins2-03.pdf |Gravity Tree Walk}} 2. Mar. 2020: {{ :​spin:​sins2-03.pdf |Gravity Tree Walk}}
  
-16. Mar. 2020: **Lecture Notes will appear today!**+16./23. Mar. 2020: {{ :​spin:​sins2-04.pdf |Introduction to SPH}} (Videos sph1.mp4 and sph2.mp4 **see above link**) 
 + 
 +30. Mar. 2020: {{ :​spin:​sins2-05.pdf |SPH Continued}} (Videos sph3.mp4 and sph4.mp4 **see above link**) 
 + 
 +6. Apr. 2020: {{ :​spin:​sins2-06.pdf |SPH Continued}} (Video sph5.mp4 ​ **see above link**) 
 + 
 +20. Apr. 2020: {{ :​spin:​sins2-07.pdf |2-d Ising Model}} (Video ising.mp4 ​ **see above link**) 
 + 
 +27. Apr. 2020: {{ :​spin:​sins2-08.pdf |2-d Traveling salesman problem}} (Video tsp.mp4 ​ **see above link**) 
 + 
 +3. May 2020: **Start of group projects!**
 ====== Assignments ====== ====== Assignments ======
  
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 ====== List of assignments ====== ====== List of assignments ======
  
-1. **Extended to Sunday 15.03.2020**: ​k-Nearest Neighbors algorithm (you can set k=8 or other values to test). You should check the code via direct computation (O(N^2)). Solution is expected to include a priority queue over the 8 NN particles, but could also explore the use of a further prioq over the nearest cells during the treewalk as discussed in the lecture.+1.k-Nearest Neighbors algorithm (you can set k=8 or other values to test). You should check the code via direct computation (O(N^2)). Solution is expected to include a priority queue over the 8 NN particles, but could also explore the use of a further prioq over the nearest cells during the treewalk as discussed in the lecture.
  
-2. Gravity simulation using 2-D trees. Implement a 2-D gravity tree-code to solve the forces between the 12'095 planetesimals in the early solar system. While the data structure is 2-D, the forces and motions are actually 3-D. The data file below contains the planetesimals in the following format (one per line):+2.  ​**Extended to Sunday 22.03.2020**: ​Gravity simulation using 2-D trees. Implement a 2-D gravity tree-code to solve the forces between the 12'095 planetesimals in the early solar system. While the data structure is 2-D, the forces and motions are actually 3-D. The data file below contains the planetesimals in the following format (one per line):
 <x y z vx vy vz m r> in unit of AU, AU/day, solar mass and AU. Recall these are the same units used in the ESC201 course for the solar system simulations. You will have to use the Gaussian gravitational constant k^2 instead of G. <x y z vx vy vz m r> in unit of AU, AU/day, solar mass and AU. Recall these are the same units used in the ESC201 course for the solar system simulations. You will have to use the Gaussian gravitational constant k^2 instead of G.
  
 {{ :​spin:​esc202-planetesimals.zip | esc202-planetesimals data file}} {{ :​spin:​esc202-planetesimals.zip | esc202-planetesimals data file}}
 +
 +3. **SPH Density calculation using Kernel**: You can use the data set from your planetesimals simulations to calculate the densities and make nice color density plots of the planetesimal disk. **As discussed in the Zoom meeting:** you should try to put uniform randomly distributed particles in a box from [0,1)x[0,1) (2-D) and calculate the density. You should see a bias that the density is too low at the edges. If you do this with a correctly working working periodic boundary condition density code you should no longer see this bias. Please think about how to efficiently calculate the density using nearest neighbors with periodic boundary conditions. Even better, implement it in your code and test it!
 +
 +4. **Sedov Taylor Explosion in SPH**: Set up a uniform grid of SPH particles in a 2-D unit cell. Make it so that there are an odd number of particle on a side, such that you have a particle centered exactly in the center of the unit cell. All particle should have v = 0 and mass = 1/N, where N is the total number of particles such that the mass of the fluid in the unit cell is 1. If we use gamma=2, then for e=1 we have c=sqrt(2) for all particles and the SPH code should maintain the uniform density as everything should be in pressure equilibrium. Test this. Now set the specific internal energy of the central particle to e = 100! Now the gas should react by producing the Sedov-Taylor blast wave. You will have to think about the appropriate timestep for the simulation. Think back to the Courant Condition from the first semester, or simply experiment with different values (hint: you know the sound speed, but what is the grid speed? What defines a resolution length scale here? h? So could we regard h/delta_t as a "grid speed"?​
 +
 +5. **2-d Ising Model**
 +
 +6. **2-d Travelling Salesman Problem**
 +
spin/esc202_fs2020.1584340116.txt.gz · Last modified: 2020/03/16 07:28 by stadel