add files

activation.py

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+import torch
+from torch.autograd import Function
+from torch.cuda.amp import custom_bwd, custom_fwd 
+
+class _trunc_exp(Function):
+    @staticmethod
+    @custom_fwd(cast_inputs=torch.float)
+    def forward(ctx, x):
+        ctx.save_for_backward(x)
+        return torch.exp(x)
+
+    @staticmethod
+    @custom_bwd
+    def backward(ctx, g):
+        x = ctx.saved_tensors[0]
+        return g * torch.exp(x.clamp(max=15))
+
+trunc_exp = _trunc_exp.apply

encoding.py

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+import torch
+import torch.nn as nn
+import torch.nn.functional as F
+
+class FreqEncoder_torch(nn.Module):
+    def __init__(self, input_dim, max_freq_log2, N_freqs,
+                 log_sampling=True, include_input=True,
+                 periodic_fns=(torch.sin, torch.cos)):
+
+        super().__init__()
+
+        self.input_dim = input_dim
+        self.include_input = include_input
+        self.periodic_fns = periodic_fns
+
+        self.output_dim = 0
+        if self.include_input:
+            self.output_dim += self.input_dim
+
+        self.output_dim += self.input_dim * N_freqs * len(self.periodic_fns)
+
+        if log_sampling:
+            self.freq_bands = 2 ** torch.linspace(0, max_freq_log2, N_freqs)
+        else:
+            self.freq_bands = torch.linspace(2 ** 0, 2 ** max_freq_log2, N_freqs)
+
+        self.freq_bands = self.freq_bands.numpy().tolist()
+
+    def forward(self, input, **kwargs):
+
+        out = []
+        if self.include_input:
+            out.append(input)
+
+        for i in range(len(self.freq_bands)):
+            freq = self.freq_bands[i]
+            for p_fn in self.periodic_fns:
+                out.append(p_fn(input * freq))
+
+        out = torch.cat(out, dim=-1)
+
+        return out
+
+def get_encoder(encoding, input_dim=3, 
+                multires=6, 
+                degree=4,
+                num_levels=16, level_dim=2, base_resolution=16, log2_hashmap_size=19, desired_resolution=2048, align_corners=False,
+                **kwargs):
+
+    if encoding == 'None':
+        return lambda x, **kwargs: x, input_dim
+
+    elif encoding == 'frequency_torch':
+        encoder = FreqEncoder_torch(input_dim=input_dim, max_freq_log2=multires-1, N_freqs=multires, log_sampling=True)
+
+    elif encoding == 'frequency': # CUDA implementation, faster than torch.
+        from freqencoder import FreqEncoder
+        encoder = FreqEncoder(input_dim=input_dim, degree=multires)
+
+    elif encoding == 'sphere_harmonics':
+        from shencoder import SHEncoder
+        encoder = SHEncoder(input_dim=input_dim, degree=degree)
+
+    elif encoding == 'hashgrid':
+        from gridencoder import GridEncoder
+        encoder = GridEncoder(input_dim=input_dim, num_levels=num_levels, level_dim=level_dim, base_resolution=base_resolution, log2_hashmap_size=log2_hashmap_size, desired_resolution=desired_resolution, gridtype='hash', align_corners=align_corners)
+
+    elif encoding == 'tiledgrid':
+        from gridencoder import GridEncoder
+        encoder = GridEncoder(input_dim=input_dim, num_levels=num_levels, level_dim=level_dim, base_resolution=base_resolution, log2_hashmap_size=log2_hashmap_size, desired_resolution=desired_resolution, gridtype='tiled', align_corners=align_corners)
+
+    else:
+        raise NotImplementedError('Unknown encoding mode, choose from [None, frequency, sphere_harmonics, hashgrid, tiledgrid]')
+
+    return encoder, encoder.output_dim

freqencoder/__init__.py

@@ -0,0 +1 @@
+from .freq import FreqEncoder

freqencoder/backend.py

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+import os
+from torch.utils.cpp_extension import load
+
+_src_path = os.path.dirname(os.path.abspath(__file__))
+
+nvcc_flags = [
+    '-O3', '-std=c++14',
+    '-U__CUDA_NO_HALF_OPERATORS__', '-U__CUDA_NO_HALF_CONVERSIONS__', '-U__CUDA_NO_HALF2_OPERATORS__',
+    '-use_fast_math'
+]
+
+if os.name == "posix":
+    c_flags = ['-O3', '-std=c++14']
+elif os.name == "nt":
+    c_flags = ['/O2', '/std:c++17']
+
+    # find cl.exe
+    def find_cl_path():
+        import glob
+        for edition in ["Enterprise", "Professional", "BuildTools", "Community"]:
+            paths = sorted(glob.glob(r"C:\\Program Files (x86)\\Microsoft Visual Studio\\*\\%s\\VC\\Tools\\MSVC\\*\\bin\\Hostx64\\x64" % edition), reverse=True)
+            if paths:
+                return paths[0]
+
+    # If cl.exe is not on path, try to find it.
+    if os.system("where cl.exe >nul 2>nul") != 0:
+        cl_path = find_cl_path()
+        if cl_path is None:
+            raise RuntimeError("Could not locate a supported Microsoft Visual C++ installation")
+        os.environ["PATH"] += ";" + cl_path
+
+_backend = load(name='_freqencoder',
+                extra_cflags=c_flags,
+                extra_cuda_cflags=nvcc_flags,
+                sources=[os.path.join(_src_path, 'src', f) for f in [
+                    'freqencoder.cu',
+                    'bindings.cpp',
+                ]],
+                )
+
+__all__ = ['_backend']

freqencoder/freq.py

@@ -0,0 +1,77 @@
+import numpy as np
+
+import torch
+import torch.nn as nn
+from torch.autograd import Function
+from torch.autograd.function import once_differentiable
+from torch.cuda.amp import custom_bwd, custom_fwd 
+
+try:
+    import _freqencoder as _backend
+except ImportError:
+    from .backend import _backend
+
+
+class _freq_encoder(Function):
+    @staticmethod
+    @custom_fwd(cast_inputs=torch.float32) # force float32 for better precision
+    def forward(ctx, inputs, degree, output_dim):
+        # inputs: [B, input_dim], float 
+        # RETURN: [B, F], float
+
+        if not inputs.is_cuda: inputs = inputs.cuda()
+        inputs = inputs.contiguous()
+
+        B, input_dim = inputs.shape # batch size, coord dim
+
+        outputs = torch.empty(B, output_dim, dtype=inputs.dtype, device=inputs.device)
+
+        _backend.freq_encode_forward(inputs, B, input_dim, degree, output_dim, outputs)
+
+        ctx.save_for_backward(inputs, outputs)
+        ctx.dims = [B, input_dim, degree, output_dim]
+
+        return outputs
+
+    @staticmethod
+    #@once_differentiable
+    @custom_bwd
+    def backward(ctx, grad):
+        # grad: [B, C * C]
+
+        grad = grad.contiguous()
+        inputs, outputs = ctx.saved_tensors
+        B, input_dim, degree, output_dim = ctx.dims
+
+        grad_inputs = torch.zeros_like(inputs)
+        _backend.freq_encode_backward(grad, outputs, B, input_dim, degree, output_dim, grad_inputs)
+
+        return grad_inputs, None, None
+
+
+freq_encode = _freq_encoder.apply
+
+
+class FreqEncoder(nn.Module):
+    def __init__(self, input_dim=3, degree=4):
+        super().__init__()
+
+        self.input_dim = input_dim
+        self.degree = degree
+        self.output_dim = input_dim + input_dim * 2 * degree
+
+    def __repr__(self):
+        return f"FreqEncoder: input_dim={self.input_dim} degree={self.degree} output_dim={self.output_dim}"
+
+    def forward(self, inputs, **kwargs):
+        # inputs: [..., input_dim]
+        # return: [..., ]
+
+        prefix_shape = list(inputs.shape[:-1])
+        inputs = inputs.reshape(-1, self.input_dim)
+
+        outputs = freq_encode(inputs, self.degree, self.output_dim)
+
+        outputs = outputs.reshape(prefix_shape + [self.output_dim])
+
+        return outputs

freqencoder/setup.py

@@ -0,0 +1,51 @@
+import os
+from setuptools import setup
+from torch.utils.cpp_extension import BuildExtension, CUDAExtension
+
+_src_path = os.path.dirname(os.path.abspath(__file__))
+
+nvcc_flags = [
+    '-O3', '-std=c++14',
+    '-U__CUDA_NO_HALF_OPERATORS__', '-U__CUDA_NO_HALF_CONVERSIONS__', '-U__CUDA_NO_HALF2_OPERATORS__',
+    '-use_fast_math'
+]
+
+if os.name == "posix":
+    c_flags = ['-O3', '-std=c++14']
+elif os.name == "nt":
+    c_flags = ['/O2', '/std:c++17']
+
+    # find cl.exe
+    def find_cl_path():
+        import glob
+        for edition in ["Enterprise", "Professional", "BuildTools", "Community"]:
+            paths = sorted(glob.glob(r"C:\\Program Files (x86)\\Microsoft Visual Studio\\*\\%s\\VC\\Tools\\MSVC\\*\\bin\\Hostx64\\x64" % edition), reverse=True)
+            if paths:
+                return paths[0]
+
+    # If cl.exe is not on path, try to find it.
+    if os.system("where cl.exe >nul 2>nul") != 0:
+        cl_path = find_cl_path()
+        if cl_path is None:
+            raise RuntimeError("Could not locate a supported Microsoft Visual C++ installation")
+        os.environ["PATH"] += ";" + cl_path
+
+setup(
+    name='freqencoder', # package name, import this to use python API
+    ext_modules=[
+        CUDAExtension(
+            name='_freqencoder', # extension name, import this to use CUDA API
+            sources=[os.path.join(_src_path, 'src', f) for f in [
+                'freqencoder.cu',
+                'bindings.cpp',
+            ]],
+            extra_compile_args={
+                'cxx': c_flags,
+                'nvcc': nvcc_flags,
+            }
+        ),
+    ],
+    cmdclass={
+        'build_ext': BuildExtension,
+    }
+)

freqencoder/src/bindings.cpp

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+#include <torch/extension.h>
+
+#include "freqencoder.h"
+
+PYBIND11_MODULE(TORCH_EXTENSION_NAME, m) {
+    m.def("freq_encode_forward", &freq_encode_forward, "freq encode forward (CUDA)");
+    m.def("freq_encode_backward", &freq_encode_backward, "freq encode backward (CUDA)");
+}