Running the Simulation - 2024.1 English - XD100

Python Simulations on x86 Machine

Review the test.py file. Notice that it runs three unit tests: test_random_x1, test_random_x10, and test_random_x100. Each unit test creates two instances of the Particles class: particles_i and particles_j. Each Particles object contains arrays of floating point values for the particle positions, particle velocities, and mass (x y z vx vy vz m). These arrays are initalized with random values with the setSphereInitialConditions() function in pylib/particles.py file. The x and y positions are constrained to be in a sphere by invoking cos() and sin() functions. The remaining constrains are as follows:

• minimum z initial position = -1000

• maximum z initial position = 1000

• minimum mass = 10

• maximum mass = 110

• minimum inital velocity = -2.0

• maximum inital velocity = 2.0

• timestep (ts) = 1

• softening factor² (sf²)= 1000

Each unit test then calls the pylib/nbody.py’s compute() function passing in the particles_i and particles_j objects as inputs. The nbody.compute() function is the vectorized python implementation of the N-Body Simulator and each call simulates 1 timestep. The nbody.compute() function outputs a new Particles object with the new x y z vx vy vz m floating point arrays.

Each unit test simulates a different number of particles for 1 timestep.

The 100 tile AI Engine design simulates 12,800 particles. The single tile AI Engine design (x1_design) simulates 128 particles, and the 10 tile AI Engine design (x10_design) simulates 1280 particles.

Results

You should see something similar to the following execution times for the python simulation.

...
test_random_x1 (__main__.PySimUnitTest)
Sets all x,y,z,vx,vy,vz,m to be random values. ... Simulating 128 particles for 1 timestep
Elapsed time for NBody Simulator executed in x86 machines using python is 0.019344806671142578 seconds ...
ok
test_random_x10 (__main__.PySimUnitTest)
Sets all x,y,z,vx,vy,vz,m to be random values. ... Simulating 1280 particles for 1 timestep
Elapsed time for NBody Simulator executed in x86 machines using python is 0.2165219783782959 seconds ...
ok
test_random_x100 (__main__.PySimUnitTest)
Sets all x,y,z,vx,vy,vz,m to be random values. ... Simulating 12800 particles for 1 timestep
Elapsed time for NBody Simulator executed in x86 machines using python is 14.963038682937622 seconds ...
ok

Following are animations created from running the Python N-Body Simulator for 300 timesteps.

(Optional) Creating Animation GiFs

You can create these .gifs with the following command:

Estimated time: 3 hours

make animations

Next Steps

After running the Python NBody Simulator, you are ready to move to the next module, Module 02-AI Engine Design.