When I try to run the pbf example, I got

[Taichi] version 1.7.2, llvm 15.0.5, commit 0131dce9, osx, python 3.11.9
[Taichi] Starting on arch=metal
Traceback (most recent call last):
  File "/Users/minchen/Desktop/solidSimBook/code/14_pbf/simulator.py", line 519, in <module>
    main()
  File "/Users/minchen/Desktop/solidSimBook/code/14_pbf/simulator.py", line 506, in main
    scene.lines(np.array([start_corner, end_corner], dtype=np.float32), color=(0.6, 0.6, 0.6), width=1)
  File "/Users/minchen/Library/Python/3.11/lib/python/site-packages/taichi/ui/scene.py", line 166, in lines
    copy_all_to_vbo(vbo, vertices, 0, 0, per_vertex_color if has_per_vertex_color else 0)
  File "/Users/minchen/Library/Python/3.11/lib/python/site-packages/taichi/lang/kernel_impl.py", line 1113, in wrapped
    return primal(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/minchen/Library/Python/3.11/lib/python/site-packages/taichi/lang/kernel_impl.py", line 1043, in __call__
    key = self.ensure_compiled(*args)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/minchen/Library/Python/3.11/lib/python/site-packages/taichi/lang/kernel_impl.py", line 1009, in ensure_compiled
    instance_id, arg_features = self.mapper.lookup(args)
                                ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/minchen/Library/Python/3.11/lib/python/site-packages/taichi/lang/kernel_impl.py", line 513, in lookup
    if key not in self.mapping:
       ^^^^^^^^^^^^^^^^^^^^^^^
TypeError: unhashable type: 'numpy.ndarray'

I guess this might be a python version issue. Which python are you using?

Hi Minchen, sorry, I should have specified the version! Just created a new environment with python 3.10.17 from scratch and this works for me:

(test_pb) ➜ zzigak @ mbp ~/test_pb uv pip list                                                                                                                               git:(main)
Package        Version
-------------- -------
colorama       0.4.6
dill           0.4.0
markdown-it-py 4.0.0
mdurl          0.1.2
numpy          2.2.6
pygments       2.19.2
rich           14.2.0
taichi         1.7.4

I think the crash occurs because Taichi v1.7.2 fails to recognize the NumPy array as a data container (runtime argument), incorrectly treating it as a template argument that requires hashing

For visualization i recommend putting the window into full screen for proper rendering of particles. Please do tell if this works for you!

The same version works for pbd_cloth (need to add warp-lang) example and viscoplastic mpm example too. For pbd_cloth you need to enable animation first before moving the control point, but it should be a simple fix to only allow that button to work when animation is enabled.

No worries! Updating taichi to 1.7.4 works! It would be great to specify the required versions in the readme.

All examples are super cool! I really enjoyed playing with them. Do you think it would be better to separate each PBD implementation example to multiple files so that the code is easier to read?

Thanks, glad it worked! Yes, we could split each implementation. What granularity did you have in mind? We could maybe have one file for the constraints and one for the solver? Or one file for each constraint?

I think one for each constraint, one for the simulator, and one for the solver for a single time step would be great, just like the mass-spring and IPC examples. What do you think?

Yes, I had that in mind, sounds good! I can try to do that this week.

Sounds great, no rush!