Remove torch dependency from geometry module (#964)

Summary:
Pull Request resolved: #964

Removes all torch/aten dependencies from the pymomentum.geometry module now
that all geometry operations have been migrated to numpy arrays. This includes:
- Removing torch header includes from C++ source files
- Removing torch import from the Python module initialization
- Removing torch from BUCK python_typing_deps
- Removing PYMOMENTUM_LIMITED_TORCH_API guards (no longer needed)
- Regenerating geometry.pyi to reflect numpy-based API (to_arrays instead of to_tensors)

The geometry module now operates entirely on numpy arrays via the Buffer
protocol. The diff_geometry module retains its torch dependency for
differentiable operations.

Reviewed By: jeongseok-meta

Differential Revision: D89893026

Author: cdtwigg

pymomentum/geometry/character_pybind.cpp

@@ -12,10 +12,6 @@
 #include "pymomentum/geometry/momentum_geometry.h"
 #include "pymomentum/geometry/momentum_io.h"
 
-// Keep tensor skinning for functions that don't have array equivalents yet
-#include "pymomentum/tensor_momentum/tensor_skinning.h"
-#include "pymomentum/torch_bridge.h"
-
 #include <momentum/character/blend_shape.h>
 #include <momentum/character/character.h>
 #include <momentum/character/character_utility.h>

pymomentum/geometry/geometry_pybind.cpp

@@ -74,14 +74,6 @@ PYBIND11_MODULE(geometry, m) {
   m.doc() = "Geometry and forward kinematics for momentum models.  ";
   m.attr("__name__") = "pymomentum.geometry";
 
-#ifdef PYMOMENTUM_LIMITED_TORCH_API
-  m.attr("AUTOGRAD_ENABLED") = false;
-#else
-  m.attr("AUTOGRAD_ENABLED") = true;
-#endif
-
-  pybind11::module_::import("torch"); // @dep=//caffe2:torch
-
   m.attr("PARAMETERS_PER_JOINT") = mm::kParametersPerJoint;
 
   py::enum_<mm::FbxUpVector>(m, "FbxUpVector")

pymomentum/geometry/momentum_geometry.cpp

@@ -38,20 +38,12 @@
 
 #include <dispenso/parallel_for.h>
 
-#ifndef PYMOMENTUM_LIMITED_TORCH_API
-#include <torch/csrc/jit/python/python_ivalue.h>
-#endif
 #include <Eigen/Core>
 
 #include <cstdint>
 
 namespace py = pybind11;
 
-#ifndef PYMOMENTUM_LIMITED_TORCH_API
-using torch::autograd::AutogradContext;
-using torch::autograd::variable_list;
-#endif
-
 namespace pymomentum {
 
 template <typename T>

pymomentum/test/test_blend_shape.py

@@ -8,14 +8,15 @@
 import unittest
 
 import numpy as np
+import pymomentum.diff_geometry as pym_diff_geometry
 import pymomentum.geometry as pym_geometry
 import pymomentum.skel_state as pym_skel_state
 import pymomentum.solver as pym_solver
 import torch
 from pymomentum.solver import ErrorFunctionType
 
 # Flag to check if autograd is enabled (disabled in arvr build modes)
-AUTOGRAD_ENABLED: bool = pym_geometry.AUTOGRAD_ENABLED
+AUTOGRAD_ENABLED: bool = pym_diff_geometry.AUTOGRAD_ENABLED
 
 
 def _build_shape_vectors(

pymomentum/test/test_pose_prior.py

@@ -16,7 +16,7 @@
 logger: logging.Logger = logging.getLogger(__name__)
 
 # Flag to check if autograd is enabled (disabled in arvr build modes)
-AUTOGRAD_ENABLED: bool = pym_geometry.AUTOGRAD_ENABLED
+AUTOGRAD_ENABLED: bool = pym_diff_geometry.AUTOGRAD_ENABLED
 
 
 class TestPosePrior(unittest.TestCase):

pymomentum/test/test_sequence_ik.py

@@ -13,7 +13,7 @@
 import torch
 from pymomentum.solver import ErrorFunctionType
 
-AUTOGRAD_ENABLED: bool = pym_geometry.AUTOGRAD_ENABLED
+AUTOGRAD_ENABLED: bool = pym_diff_geometry.AUTOGRAD_ENABLED
 
 
 class TestSolver(unittest.TestCase):

pymomentum/test/test_skel_state.py

@@ -9,14 +9,15 @@
 from typing import Tuple
 
 import numpy as np
+import pymomentum.diff_geometry as pym_diff_geometry
 import pymomentum.geometry as pym_geometry
 import pymomentum.quaternion as pym_quaternion
 import pymomentum.skel_state as pym_skel_state
 import torch
 from torch.nn import Parameter as P
 
 # Flag to check if autograd is enabled (disabled in arvr build modes)
-AUTOGRAD_ENABLED: bool = pym_geometry.AUTOGRAD_ENABLED
+AUTOGRAD_ENABLED: bool = pym_diff_geometry.AUTOGRAD_ENABLED
 
 
 def generate_skel_state_components(