gaussian_model_4d.py

#
# Copyright (C) 2023, Inria
# GRAPHDECO research group, https://team.inria.fr/graphdeco
# All rights reserved.
#
# This software is free for non-commercial, research and evaluation use 
# under the terms of the LICENSE.md file.
#
# For inquiries contact  george.drettakis@inria.fr
#

import torch
import numpy as np
from utils.general_utils import inverse_sigmoid, get_expon_lr_func, build_rotation
from torch import nn
import os
from utils.system_utils import mkdir_p
from plyfile import PlyData, PlyElement
from random import randint
from utils.sh_utils import RGB2SH
from simple_knn._C import distCUDA2
from mesh import Mesh
from mesh_utils import decimate_mesh, clean_mesh
from utils.graphics_utils import BasicPointCloud
from utils.general_utils import strip_symmetric, build_scaling_rotation
from scene.deformation import deform_network
from scene.regulation import compute_plane_smoothness


def gaussian_3d_coeff(xyzs, covs):
    # xyzs: [N, 3]
    # covs: [N, 6]
    x, y, z = xyzs[:, 0], xyzs[:, 1], xyzs[:, 2]
    a, b, c, d, e, f = covs[:, 0], covs[:, 1], covs[:, 2], covs[:, 3], covs[:, 4], covs[:, 5]

    # eps must be small enough !!!
    inv_det = 1 / (a * d * f + 2 * e * c * b - e**2 * a - c**2 * d - b**2 * f + 1e-24)
    inv_a = (d * f - e**2) * inv_det
    inv_b = (e * c - b * f) * inv_det
    inv_c = (e * b - c * d) * inv_det
    inv_d = (a * f - c**2) * inv_det
    inv_e = (b * c - e * a) * inv_det
    inv_f = (a * d - b**2) * inv_det

    power = -0.5 * (x**2 * inv_a + y**2 * inv_d + z**2 * inv_f) - x * y * inv_b - x * z * inv_c - y * z * inv_e

    power[power > 0] = -1e10 # abnormal values... make weights 0
        
    return torch.exp(power)

class GaussianModel:

    def setup_functions(self):
        def build_covariance_from_scaling_rotation(scaling, scaling_modifier, rotation):
            L = build_scaling_rotation(scaling_modifier * scaling, rotation)
            actual_covariance = L @ L.transpose(1, 2)
            symm = strip_symmetric(actual_covariance)
            return symm
        
        self.scaling_activation = torch.exp
        self.scaling_inverse_activation = torch.log

        self.covariance_activation = build_covariance_from_scaling_rotation

        self.opacity_activation = torch.sigmoid
        self.inverse_opacity_activation = inverse_sigmoid

        self.rotation_activation = torch.nn.functional.normalize


    def __init__(self, sh_degree : int, args):
        self.active_sh_degree = 0
        self.max_sh_degree = sh_degree  
        self._xyz = torch.empty(0)
        # self._deformation =  torch.empty(0)
        self._deformation = deform_network(args)
        # self.grid = TriPlaneGrid()
        self._features_dc = torch.empty(0)
        self._features_rest = torch.empty(0)
        self._scaling = torch.empty(0)
        self._rotation = torch.empty(0)
        self._opacity = torch.empty(0)
        self.max_radii2D = torch.empty(0)
        self.xyz_gradient_accum = torch.empty(0)
        self.denom = torch.empty(0)
        self.optimizer = None
        self.percent_dense = 0
        self.spatial_lr_scale = 0
        self._deformation_table = torch.empty(0)
        self.setup_functions()

    def capture(self):
        return (
            self.active_sh_degree,
            self._xyz,
            self._deformation.state_dict(),
            self._deformation_table,
            # self.grid,
            self._features_dc,
            self._features_rest,
            self._scaling,
            self._rotation,
            self._opacity,
            self.max_radii2D,
            self.xyz_gradient_accum,
            self.denom,
            self.optimizer.state_dict(),
            self.spatial_lr_scale,
        )
    
    def restore(self, model_args, training_args):
        (self.active_sh_degree, 
        self._xyz, 
        self._deformation_table,
        self._deformation,
        # self.grid,
        self._features_dc, 
        self._features_rest,
        self._scaling, 
        self._rotation, 
        self._opacity,
        self.max_radii2D, 
        xyz_gradient_accum, 
        denom,
        opt_dict, 
        self.spatial_lr_scale) = model_args
        self.training_setup(training_args)
        self.xyz_gradient_accum = xyz_gradient_accum
        self.denom = denom
        self.optimizer.load_state_dict(opt_dict)

    @property
    def get_scaling(self):
        return self.scaling_activation(self._scaling)
    
    @property
    def get_rotation(self):
        return self.rotation_activation(self._rotation)
    
    @property
    def get_xyz(self):
        return self._xyz

    @property
    def get_features(self):
        features_dc = self._features_dc
        features_rest = self._features_rest
        return torch.cat((features_dc, features_rest), dim=1)
    
    @property
    def get_opacity(self):
        return self.opacity_activation(self._opacity)


    def get_deformed_everything(self, time):
        means3D = self.get_xyz
        time = torch.tensor(time).to(means3D.device).repeat(means3D.shape[0],1)
        time = ((time.float() / self.T) - 0.5) * 2

        opacity = self._opacity
        scales = self._scaling
        rotations = self._rotation

        deformation_point = self._deformation_table
        means3D_deform, scales_deform, rotations_deform, opacity_deform = self._deformation(means3D[deformation_point], scales[deformation_point], 
                                                    rotations[deformation_point], opacity[deformation_point],
                                                    time[deformation_point])

        means3D_final =  means3D + means3D_deform
        rotations_final =  rotations + rotations_deform
        scales_final =  scales + scales_deform
        opacity_final = opacity

        return means3D_final, rotations_final, scales_final, opacity_final


    
    @torch.no_grad()
    def extract_fields_t(self, resolution=128, num_blocks=16, relax_ratio=1.5, t=0):
        # resolution: resolution of field
        
        block_size = 2 / num_blocks

        assert resolution % block_size == 0
        split_size = resolution // num_blocks

        xyzs, rotation, scale, opacities = self.get_deformed_everything(t)

        scale = self.scaling_activation(scale)
        opacities = self.opacity_activation(opacities)

        # pre-filter low opacity gaussians to save computation
        mask = (opacities > 0.005).squeeze(1)

        opacities = opacities[mask]
        xyzs = xyzs[mask]
        stds = scale[mask]
        
        # normalize to ~ [-1, 1]
        mn, mx = xyzs.amin(0), xyzs.amax(0)
        self.center = (mn + mx) / 2
        self.scale = 1.8 / (mx - mn).amax().item()

        xyzs = (xyzs - self.center) * self.scale
        stds = stds * self.scale

        covs = self.covariance_activation(stds, 1, rotation[mask])

        # tile
        device = opacities.device
        occ = torch.zeros([resolution] * 3, dtype=torch.float32, device=device)

        X = torch.linspace(-1, 1, resolution).split(split_size)
        Y = torch.linspace(-1, 1, resolution).split(split_size)
        Z = torch.linspace(-1, 1, resolution).split(split_size)


        # loop blocks (assume max size of gaussian is small than relax_ratio * block_size !!!)
        for xi, xs in enumerate(X):
            for yi, ys in enumerate(Y):
                for zi, zs in enumerate(Z):
                    xx, yy, zz = torch.meshgrid(xs, ys, zs)
                    # sample points [M, 3]
                    pts = torch.cat([xx.reshape(-1, 1), yy.reshape(-1, 1), zz.reshape(-1, 1)], dim=-1).to(device)
                    # in-tile gaussians mask
                    vmin, vmax = pts.amin(0), pts.amax(0)
                    vmin -= block_size * relax_ratio
                    vmax += block_size * relax_ratio
                    mask = (xyzs < vmax).all(-1) & (xyzs > vmin).all(-1)
                    # if hit no gaussian, continue to next block
                    if not mask.any():
                        continue
                    mask_xyzs = xyzs[mask] # [L, 3]
                    mask_covs = covs[mask] # [L, 6]
                    mask_opas = opacities[mask].view(1, -1) # [L, 1] --> [1, L]

                    # query per point-gaussian pair.
                    g_pts = pts.unsqueeze(1).repeat(1, mask_covs.shape[0], 1) - mask_xyzs.unsqueeze(0) # [M, L, 3]
                    g_covs = mask_covs.unsqueeze(0).repeat(pts.shape[0], 1, 1) # [M, L, 6]

                    # batch on gaussian to avoid OOM
                    batch_g = 1024
                    val = 0
                    for start in range(0, g_covs.shape[1], batch_g):
                        end = min(start + batch_g, g_covs.shape[1])
                        w = gaussian_3d_coeff(g_pts[:, start:end].reshape(-1, 3), g_covs[:, start:end].reshape(-1, 6)).reshape(pts.shape[0], -1) # [M, l]
                        val += (mask_opas[:, start:end] * w).sum(-1)
                    
                    # kiui.lo(val, mask_opas, w)
                
                    occ[xi * split_size: xi * split_size + len(xs), 
                        yi * split_size: yi * split_size + len(ys), 
                        zi * split_size: zi * split_size + len(zs)] = val.reshape(len(xs), len(ys), len(zs)) 
        return occ

    def extract_mesh_t(self, path, density_thresh=1, t=0, resolution=128, decimate_target=1e5):

        os.makedirs(os.path.dirname(path), exist_ok=True)

        occ = self.extract_fields_t(resolution, t=t).detach().cpu().numpy()

        import mcubes
        vertices, triangles = mcubes.marching_cubes(occ, density_thresh)
        vertices = vertices / (resolution - 1.0) * 2 - 1

        # transform back to the original space
        vertices = vertices / self.scale + self.center.detach().cpu().numpy()

        vertices, triangles = clean_mesh(vertices, triangles, remesh=True, remesh_size=0.015)
        if decimate_target > 0 and triangles.shape[0] > decimate_target:
            vertices, triangles = decimate_mesh(vertices, triangles, decimate_target)

        v = torch.from_numpy(vertices.astype(np.float32)).contiguous().cuda()
        f = torch.from_numpy(triangles.astype(np.int32)).contiguous().cuda()

        print(
            f"[INFO] marching cubes result: {v.shape} ({v.min().item()}-{v.max().item()}), {f.shape}"
        )

        mesh = Mesh(v=v, f=f, device='cuda')

        return mesh
    
    def get_covariance(self, scaling_modifier = 1):
        return self.covariance_activation(self.get_scaling, scaling_modifier, self._rotation)

    def oneupSHdegree(self):
        if self.active_sh_degree < self.max_sh_degree:
            self.active_sh_degree += 1

    def create_from_pcd(self, pcd : BasicPointCloud, spatial_lr_scale : float, time_line: int):
        self.spatial_lr_scale = spatial_lr_scale
        fused_point_cloud = torch.tensor(np.asarray(pcd.points)).float().cuda()
        fused_color = RGB2SH(torch.tensor(np.asarray(pcd.colors)).float().cuda())
        features = torch.zeros((fused_color.shape[0], 3, (self.max_sh_degree + 1) ** 2)).float().cuda()
        features[:, :3, 0 ] = fused_color
        features[:, 3:, 1:] = 0.0

        print("Number of points at initialisation : ", fused_point_cloud.shape[0])

        dist2 = torch.clamp_min(distCUDA2(torch.from_numpy(np.asarray(pcd.points)).float().cuda()), 0.0000001)
        scales = torch.log(torch.sqrt(dist2))[...,None].repeat(1, 3)
        rots = torch.zeros((fused_point_cloud.shape[0], 4), device="cuda")
        rots[:, 0] = 1

        opacities = inverse_sigmoid(0.1 * torch.ones((fused_point_cloud.shape[0], 1), dtype=torch.float, device="cuda"))

        self._xyz = nn.Parameter(fused_point_cloud.requires_grad_(True))
        self._deformation = self._deformation.to("cuda") 
        # self.grid = self.grid.to("cuda")
        self._features_dc = nn.Parameter(features[:,:,0:1].transpose(1, 2).contiguous().requires_grad_(True))
        self._features_rest = nn.Parameter(features[:,:,1:].transpose(1, 2).contiguous().requires_grad_(True))
        self._scaling = nn.Parameter(scales.requires_grad_(True))
        self._rotation = nn.Parameter(rots.requires_grad_(True))
        self._opacity = nn.Parameter(opacities.requires_grad_(True))
        self.max_radii2D = torch.zeros((self.get_xyz.shape[0]), device="cuda")
        self._deformation_table = torch.gt(torch.ones((self.get_xyz.shape[0]),device="cuda"),0)

    def training_setup(self, training_args):
        self.percent_dense = training_args.percent_dense
        self.xyz_gradient_accum = torch.zeros((self.get_xyz.shape[0], 1), device="cuda")
        self.denom = torch.zeros((self.get_xyz.shape[0], 1), device="cuda")
        self._deformation_accum = torch.zeros((self.get_xyz.shape[0],3),device="cuda")
        self.T = training_args.batch_size
        
        if training_args.optimize_gaussians:
            l = [
                {'params': [self._xyz], 'lr': training_args.position_lr_init * self.spatial_lr_scale, "name": "xyz"},
                {'params': list(self._deformation.get_mlp_parameters()), 'lr': training_args.deformation_lr_init * self.spatial_lr_scale, "name": "deformation"},
                {'params': list(self._deformation.get_grid_parameters()), 'lr': training_args.grid_lr_init * self.spatial_lr_scale, "name": "grid"},
                {'params': [self._features_dc], 'lr': training_args.feature_lr, "name": "f_dc"},
                {'params': [self._features_rest], 'lr': training_args.feature_lr / 20.0, "name": "f_rest"},
                {'params': [self._opacity], 'lr': training_args.opacity_lr, "name": "opacity"},
                {'params': [self._scaling], 'lr': training_args.scaling_lr, "name": "scaling"},
                {'params': [self._rotation], 'lr': training_args.rotation_lr, "name": "rotation"}
            ]
        else:
            l = [
                {'params': list(self._deformation.get_mlp_parameters()), 'lr': training_args.deformation_lr_init * self.spatial_lr_scale, "name": "deformation"},
                {'params': list(self._deformation.get_grid_parameters()), 'lr': training_args.grid_lr_init * self.spatial_lr_scale, "name": "grid"},
            ]

        self.optimizer = torch.optim.Adam(l, lr=0.0, eps=1e-15)
        self.xyz_scheduler_args = get_expon_lr_func(lr_init=training_args.position_lr_init*self.spatial_lr_scale,
                                                    lr_final=training_args.position_lr_final*self.spatial_lr_scale,
                                                    lr_delay_mult=training_args.position_lr_delay_mult,
                                                    max_steps=training_args.position_lr_max_steps)
        self.deformation_scheduler_args = get_expon_lr_func(lr_init=training_args.deformation_lr_init*self.spatial_lr_scale,
                                                    lr_final=training_args.deformation_lr_final*self.spatial_lr_scale,
                                                    lr_delay_mult=training_args.deformation_lr_delay_mult,
                                                    max_steps=training_args.position_lr_max_steps)    
        self.grid_scheduler_args = get_expon_lr_func(lr_init=training_args.grid_lr_init*self.spatial_lr_scale,
                                                    lr_final=training_args.grid_lr_final*self.spatial_lr_scale,
                                                    lr_delay_mult=training_args.deformation_lr_delay_mult,
                                                    max_steps=training_args.position_lr_max_steps)    

    def update_learning_rate(self, iteration):
        ''' Learning rate scheduling per step '''
        for param_group in self.optimizer.param_groups:
            if param_group["name"] == "xyz":
                lr = self.xyz_scheduler_args(iteration)
                param_group['lr'] = lr
                # return lr
            if  "grid" in param_group["name"]:
                lr = self.grid_scheduler_args(iteration)
                param_group['lr'] = lr
                # return lr
            elif param_group["name"] == "deformation":
                lr = self.deformation_scheduler_args(iteration)
                param_group['lr'] = lr
                # return lr

    def construct_list_of_attributes(self):
        l = ['x', 'y', 'z', 'nx', 'ny', 'nz']
        # All channels except the 3 DC
        for i in range(self._features_dc.shape[1]*self._features_dc.shape[2]):
            l.append('f_dc_{}'.format(i))
        for i in range(self._features_rest.shape[1]*self._features_rest.shape[2]):
            l.append('f_rest_{}'.format(i))
        l.append('opacity')
        for i in range(self._scaling.shape[1]):
            l.append('scale_{}'.format(i))
        for i in range(self._rotation.shape[1]):
            l.append('rot_{}'.format(i))
        return l
    def compute_deformation(self,time):
        
        deform = self._deformation[:,:,:time].sum(dim=-1)
        xyz = self._xyz + deform
        return xyz

    def load_model(self, path, name):
        print("loading model from exists{}".format(path))
        weight_dict = torch.load(os.path.join(path, name+"_deformation.pth"),map_location="cuda")
        self._deformation.load_state_dict(weight_dict)
        self._deformation = self._deformation.to("cuda")
        self._deformation_table = torch.gt(torch.ones((self.get_xyz.shape[0]),device="cuda"),0)
        self._deformation_accum = torch.zeros((self.get_xyz.shape[0],3),device="cuda")
        if os.path.exists(os.path.join(path, name+"_deformation_table.pth")):
            self._deformation_table = torch.load(os.path.join(path, name+"_deformation_table.pth"),map_location="cuda")
        if os.path.exists(os.path.join(path,name+"_deformation_accum.pth")):
            self._deformation_accum = torch.load(os.path.join(path, name+"_deformation_accum.pth"),map_location="cuda")
        self.max_radii2D = torch.zeros((self.get_xyz.shape[0]), device="cuda")

    def save_deformation(self, path, name):
        torch.save(self._deformation.state_dict(),os.path.join(path, name+"_deformation.pth"))
        torch.save(self._deformation_table,os.path.join(path, name+"_deformation_table.pth"))
        torch.save(self._deformation_accum,os.path.join(path, name+"_deformation_accum.pth"))

    def save_ply(self, path):
        mkdir_p(os.path.dirname(path))

        xyz = self._xyz.detach().cpu().numpy()
        normals = np.zeros_like(xyz)
        f_dc = self._features_dc.detach().transpose(1, 2).flatten(start_dim=1).contiguous().cpu().numpy()
        f_rest = self._features_rest.detach().transpose(1, 2).flatten(start_dim=1).contiguous().cpu().numpy()
        opacities = self._opacity.detach().cpu().numpy()
        scale = self._scaling.detach().cpu().numpy()
        rotation = self._rotation.detach().cpu().numpy()
        
        dtype_full = [(attribute, 'f4') for attribute in self.construct_list_of_attributes()]

        elements = np.empty(xyz.shape[0], dtype=dtype_full)
        attributes = np.concatenate((xyz, normals, f_dc, f_rest, opacities, scale, rotation), axis=1)
        elements[:] = list(map(tuple, attributes))
        el = PlyElement.describe(elements, 'vertex')
        PlyData([el]).write(path)

    def save_frame_ply(self, path, t):
        mkdir_p(os.path.dirname(path))

        xyzs, rotation, scale, opacities = self.get_deformed_everything(t)

        xyz = xyzs.detach().cpu().numpy()
        normals = np.zeros_like(xyz)
        f_dc = self._features_dc.detach().transpose(1, 2).flatten(start_dim=1).contiguous().cpu().numpy()
        f_rest = self._features_rest.detach().transpose(1, 2).flatten(start_dim=1).contiguous().cpu().numpy()
        opacities = opacities.detach().cpu().numpy()
        scale = scale.detach().cpu().numpy()
        rotation = rotation.detach().cpu().numpy()
        
        dtype_full = [(attribute, 'f4') for attribute in self.construct_list_of_attributes()]

        elements = np.empty(xyz.shape[0], dtype=dtype_full)
        attributes = np.concatenate((xyz, normals, f_dc, f_rest, opacities, scale, rotation), axis=1)
        elements[:] = list(map(tuple, attributes))
        el = PlyElement.describe(elements, 'vertex')
        PlyData([el]).write(path)
    # def save_frame_ply(self, path, t):
    #     mkdir_p(os.path.dirname(path))

    #     xyz = self._xyz.detach().cpu().numpy()
    #     normals = np.zeros_like(xyz)
    #     f_dc = self._features_dc.detach().transpose(1, 2).flatten(start_dim=1).contiguous().cpu().numpy()
    #     f_rest = self._features_rest.detach().transpose(1, 2).flatten(start_dim=1).contiguous().cpu().numpy()
    #     opacities = self._opacity.detach().cpu().numpy()
    #     scale = self._scaling.detach().cpu().numpy()
    #     rotation = self._rotation.detach().cpu().numpy()
        
    #     dtype_full = [(attribute, 'f4') for attribute in self.construct_list_of_attributes()]

    #     elements = np.empty(xyz.shape[0], dtype=dtype_full)
    #     attributes = np.concatenate((xyz, normals, f_dc, f_rest, opacities, scale, rotation), axis=1)
    #     elements[:] = list(map(tuple, attributes))
    #     el = PlyElement.describe(elements, 'vertex')
    #     PlyData([el]).write(path)
        
    def reset_opacity(self):
        opacities_new = inverse_sigmoid(torch.min(self.get_opacity, torch.ones_like(self.get_opacity)*0.01))
        optimizable_tensors = self.replace_tensor_to_optimizer(opacities_new, "opacity")
        self._opacity = optimizable_tensors["opacity"]

    def load_ply(self, path):
        self.spatial_lr_scale = 1
        plydata = PlyData.read(path)

        xyz = np.stack((np.asarray(plydata.elements[0]["x"]),
                        np.asarray(plydata.elements[0]["y"]),
                        np.asarray(plydata.elements[0]["z"])),  axis=1)
        opacities = np.asarray(plydata.elements[0]["opacity"])[..., np.newaxis]

        features_dc = np.zeros((xyz.shape[0], 3, 1))
        features_dc[:, 0, 0] = np.asarray(plydata.elements[0]["f_dc_0"])
        features_dc[:, 1, 0] = np.asarray(plydata.elements[0]["f_dc_1"])
        features_dc[:, 2, 0] = np.asarray(plydata.elements[0]["f_dc_2"])

        extra_f_names = [p.name for p in plydata.elements[0].properties if p.name.startswith("f_rest_")]
        extra_f_names = sorted(extra_f_names, key = lambda x: int(x.split('_')[-1]))
        assert len(extra_f_names)==3*(self.max_sh_degree + 1) ** 2 - 3
        features_extra = np.zeros((xyz.shape[0], len(extra_f_names)))
        for idx, attr_name in enumerate(extra_f_names):
            features_extra[:, idx] = np.asarray(plydata.elements[0][attr_name])
        # Reshape (P,F*SH_coeffs) to (P, F, SH_coeffs except DC)
        features_extra = features_extra.reshape((features_extra.shape[0], 3, (self.max_sh_degree + 1) ** 2 - 1))

        scale_names = [p.name for p in plydata.elements[0].properties if p.name.startswith("scale_")]
        scale_names = sorted(scale_names, key = lambda x: int(x.split('_')[-1]))
        scales = np.zeros((xyz.shape[0], len(scale_names)))
        for idx, attr_name in enumerate(scale_names):
            scales[:, idx] = np.asarray(plydata.elements[0][attr_name])

        rot_names = [p.name for p in plydata.elements[0].properties if p.name.startswith("rot")]
        rot_names = sorted(rot_names, key = lambda x: int(x.split('_')[-1]))
        rots = np.zeros((xyz.shape[0], len(rot_names)))
        for idx, attr_name in enumerate(rot_names):
            rots[:, idx] = np.asarray(plydata.elements[0][attr_name])

        self._xyz = nn.Parameter(torch.tensor(xyz, dtype=torch.float, device="cuda").requires_grad_(True))
        self._features_dc = nn.Parameter(torch.tensor(features_dc, dtype=torch.float, device="cuda").transpose(1, 2).contiguous().requires_grad_(True))
        self._features_rest = nn.Parameter(torch.tensor(features_extra, dtype=torch.float, device="cuda").transpose(1, 2).contiguous().requires_grad_(True))
        self._opacity = nn.Parameter(torch.tensor(opacities, dtype=torch.float, device="cuda").requires_grad_(True))
        self._scaling = nn.Parameter(torch.tensor(scales, dtype=torch.float, device="cuda").requires_grad_(True))
        self._rotation = nn.Parameter(torch.tensor(rots, dtype=torch.float, device="cuda").requires_grad_(True))
        self.active_sh_degree = self.max_sh_degree
        self.max_radii2D = torch.zeros((self.get_xyz.shape[0]), device="cuda")
        self._deformation = self._deformation.to("cuda")
        self._deformation_table = torch.gt(torch.ones((self.get_xyz.shape[0]),device="cuda"),0) # everything deformed

        print(self._xyz.shape)


    def replace_tensor_to_optimizer(self, tensor, name):
        optimizable_tensors = {}
        for group in self.optimizer.param_groups:
            if group["name"] == name:
                stored_state = self.optimizer.state.get(group['params'][0], None)
                stored_state["exp_avg"] = torch.zeros_like(tensor)
                stored_state["exp_avg_sq"] = torch.zeros_like(tensor)

                del self.optimizer.state[group['params'][0]]
                group["params"][0] = nn.Parameter(tensor.requires_grad_(True))
                self.optimizer.state[group['params'][0]] = stored_state

                optimizable_tensors[group["name"]] = group["params"][0]
        return optimizable_tensors

    def _prune_optimizer(self, mask):
        optimizable_tensors = {}
        for group in self.optimizer.param_groups:
            if len(group["params"]) > 1:
                continue
            stored_state = self.optimizer.state.get(group['params'][0], None)
            if stored_state is not None:
                stored_state["exp_avg"] = stored_state["exp_avg"][mask]
                stored_state["exp_avg_sq"] = stored_state["exp_avg_sq"][mask]

                del self.optimizer.state[group['params'][0]]
                group["params"][0] = nn.Parameter((group["params"][0][mask].requires_grad_(True)))
                self.optimizer.state[group['params'][0]] = stored_state

                optimizable_tensors[group["name"]] = group["params"][0]
            else:
                group["params"][0] = nn.Parameter(group["params"][0][mask].requires_grad_(True))
                optimizable_tensors[group["name"]] = group["params"][0]
        return optimizable_tensors

    def prune_points(self, mask):
        valid_points_mask = ~mask
        optimizable_tensors = self._prune_optimizer(valid_points_mask)

        self._xyz = optimizable_tensors["xyz"]
        self._features_dc = optimizable_tensors["f_dc"]
        self._features_rest = optimizable_tensors["f_rest"]
        self._opacity = optimizable_tensors["opacity"]
        self._scaling = optimizable_tensors["scaling"]
        self._rotation = optimizable_tensors["rotation"]
        self._deformation_accum = self._deformation_accum[valid_points_mask]
        self.xyz_gradient_accum = self.xyz_gradient_accum[valid_points_mask]
        self._deformation_table = self._deformation_table[valid_points_mask]
        self.denom = self.denom[valid_points_mask]
        self.max_radii2D = self.max_radii2D[valid_points_mask]

    def cat_tensors_to_optimizer(self, tensors_dict):
        optimizable_tensors = {}
        for group in self.optimizer.param_groups:
            if len(group["params"])>1:continue
            assert len(group["params"]) == 1
            extension_tensor = tensors_dict[group["name"]]
            stored_state = self.optimizer.state.get(group['params'][0], None)
            if stored_state is not None:

                stored_state["exp_avg"] = torch.cat((stored_state["exp_avg"], torch.zeros_like(extension_tensor)), dim=0)
                stored_state["exp_avg_sq"] = torch.cat((stored_state["exp_avg_sq"], torch.zeros_like(extension_tensor)), dim=0)

                del self.optimizer.state[group['params'][0]]
                group["params"][0] = nn.Parameter(torch.cat((group["params"][0], extension_tensor), dim=0).requires_grad_(True))
                self.optimizer.state[group['params'][0]] = stored_state

                optimizable_tensors[group["name"]] = group["params"][0]
            else:
                group["params"][0] = nn.Parameter(torch.cat((group["params"][0], extension_tensor), dim=0).requires_grad_(True))
                optimizable_tensors[group["name"]] = group["params"][0]

        return optimizable_tensors

    def densification_postfix(self, new_xyz, new_features_dc, new_features_rest, new_opacities, new_scaling, new_rotation, new_deformation_table):
        d = {"xyz": new_xyz,
        "f_dc": new_features_dc,
        "f_rest": new_features_rest,
        "opacity": new_opacities,
        "scaling" : new_scaling,
        "rotation" : new_rotation,
        # "deformation": new_deformation
       }

        optimizable_tensors = self.cat_tensors_to_optimizer(d)
        self._xyz = optimizable_tensors["xyz"]
        self._features_dc = optimizable_tensors["f_dc"]
        self._features_rest = optimizable_tensors["f_rest"]
        self._opacity = optimizable_tensors["opacity"]
        self._scaling = optimizable_tensors["scaling"]
        self._rotation = optimizable_tensors["rotation"]
        # self._deformation = optimizable_tensors["deformation"]
        
        self._deformation_table = torch.cat([self._deformation_table,new_deformation_table],-1)
        self.xyz_gradient_accum = torch.zeros((self.get_xyz.shape[0], 1), device="cuda")
        self._deformation_accum = torch.zeros((self.get_xyz.shape[0], 3), device="cuda")
        self.denom = torch.zeros((self.get_xyz.shape[0], 1), device="cuda")
        self.max_radii2D = torch.zeros((self.get_xyz.shape[0]), device="cuda")

    def densify_and_split(self, grads, grad_threshold, scene_extent, N=2):
        n_init_points = self.get_xyz.shape[0]
        # Extract points that satisfy the gradient condition
        padded_grad = torch.zeros((n_init_points), device="cuda")
        padded_grad[:grads.shape[0]] = grads.squeeze()
        selected_pts_mask = torch.where(padded_grad >= grad_threshold, True, False)
        selected_pts_mask = torch.logical_and(selected_pts_mask,
                                              torch.max(self.get_scaling, dim=1).values > self.percent_dense*scene_extent)
        if not selected_pts_mask.any():
            return
        stds = self.get_scaling[selected_pts_mask].repeat(N,1)
        means =torch.zeros((stds.size(0), 3),device="cuda")
        samples = torch.normal(mean=means, std=stds)
        rots = build_rotation(self._rotation[selected_pts_mask]).repeat(N,1,1)
        new_xyz = torch.bmm(rots, samples.unsqueeze(-1)).squeeze(-1) + self.get_xyz[selected_pts_mask].repeat(N, 1)
        new_scaling = self.scaling_inverse_activation(self.get_scaling[selected_pts_mask].repeat(N,1) / (0.8*N))
        new_rotation = self._rotation[selected_pts_mask].repeat(N,1)
        new_features_dc = self._features_dc[selected_pts_mask].repeat(N,1,1)
        new_features_rest = self._features_rest[selected_pts_mask].repeat(N,1,1)
        new_opacity = self._opacity[selected_pts_mask].repeat(N,1)
        new_deformation_table = self._deformation_table[selected_pts_mask].repeat(N)
        self.densification_postfix(new_xyz, new_features_dc, new_features_rest, new_opacity, new_scaling, new_rotation, new_deformation_table)

        prune_filter = torch.cat((selected_pts_mask, torch.zeros(N * selected_pts_mask.sum(), device="cuda", dtype=bool)))
        self.prune_points(prune_filter)

    def densify_and_clone(self, grads, grad_threshold, scene_extent):
        # Extract points that satisfy the gradient condition
        selected_pts_mask = torch.where(torch.norm(grads, dim=-1) >= grad_threshold, True, False)
        selected_pts_mask = torch.logical_and(selected_pts_mask,
                                              torch.max(self.get_scaling, dim=1).values <= self.percent_dense*scene_extent)
        
        new_xyz = self._xyz[selected_pts_mask] 
        # - 0.001 * self._xyz.grad[selected_pts_mask]
        new_features_dc = self._features_dc[selected_pts_mask]
        new_features_rest = self._features_rest[selected_pts_mask]
        new_opacities = self._opacity[selected_pts_mask]
        new_scaling = self._scaling[selected_pts_mask]
        new_rotation = self._rotation[selected_pts_mask]
        new_deformation_table = self._deformation_table[selected_pts_mask]

        self.densification_postfix(new_xyz, new_features_dc, new_features_rest, new_opacities, new_scaling, new_rotation, new_deformation_table)
        
    def prune(self, min_opacity, extent, max_screen_size):
        prune_mask = (self.get_opacity < min_opacity).squeeze()
        # prune_mask_2 = torch.logical_and(self.get_opacity <= inverse_sigmoid(0.101 , dtype=torch.float, device="cuda"), self.get_opacity >= inverse_sigmoid(0.999 , dtype=torch.float, device="cuda"))
        # prune_mask = torch.logical_or(prune_mask, prune_mask_2)
        # deformation_sum = abs(self._deformation).sum(dim=-1).mean(dim=-1) 
        # deformation_mask = (deformation_sum < torch.quantile(deformation_sum, torch.tensor([0.5]).to("cuda")))
        # prune_mask = prune_mask & deformation_mask
        if max_screen_size:
            big_points_vs = self.max_radii2D > max_screen_size
            big_points_ws = self.get_scaling.max(dim=1).values > 0.1 * extent
            prune_mask = torch.logical_or(prune_mask, big_points_vs)

            prune_mask = torch.logical_or(torch.logical_or(prune_mask, big_points_vs), big_points_ws)
        self.prune_points(prune_mask)

        torch.cuda.empty_cache()
    def densify(self, max_grad, min_opacity, extent, max_screen_size):
        grads = self.xyz_gradient_accum / self.denom
        grads[grads.isnan()] = 0.0

        self.densify_and_clone(grads, max_grad, extent)
        self.densify_and_split(grads, max_grad, extent)
    def standard_constaint(self):
        
        means3D = self._xyz.detach()
        scales = self._scaling.detach()
        rotations = self._rotation.detach()
        opacity = self._opacity.detach()
        time =  torch.tensor(0).to("cuda").repeat(means3D.shape[0],1)
        means3D_deform, scales_deform, rotations_deform, _ = self._deformation(means3D, scales, rotations, opacity, time)
        position_error = (means3D_deform - means3D)**2
        rotation_error = (rotations_deform - rotations)**2 
        scaling_erorr = (scales_deform - scales)**2
        return position_error.mean() + rotation_error.mean() + scaling_erorr.mean()


    def add_densification_stats(self, viewspace_point_tensor, update_filter):
        self.xyz_gradient_accum[update_filter] += torch.norm(viewspace_point_tensor[update_filter,:2], dim=-1, keepdim=True)
        self.denom[update_filter] += 1
    @torch.no_grad()
    def update_deformation_table(self,threshold):
        # print("origin deformation point nums:",self._deformation_table.sum())
        self._deformation_table = torch.gt(self._deformation_accum.max(dim=-1).values/100,threshold)
    def print_deformation_weight_grad(self):
        for name, weight in self._deformation.named_parameters():
            if weight.requires_grad:
                if weight.grad is None:
                    
                    print(name," :",weight.grad)
                else:
                    if weight.grad.mean() != 0:
                        print(name," :",weight.grad.mean(), weight.grad.min(), weight.grad.max())
        print("-"*50)
    def _plane_regulation(self):
        multi_res_grids = self._deformation.deformation_net.grid.grids
        total = 0
        # model.grids is 6 x [1, rank * F_dim, reso, reso]
        for grids in multi_res_grids:
            if len(grids) == 3:
                time_grids = []
            else:
                time_grids =  [0,1,3]
            for grid_id in time_grids:
                total += compute_plane_smoothness(grids[grid_id])
        return total
    def _time_regulation(self):
        multi_res_grids = self._deformation.deformation_net.grid.grids
        total = 0
        # model.grids is 6 x [1, rank * F_dim, reso, reso]
        for grids in multi_res_grids:
            if len(grids) == 3:
                time_grids = []
            else:
                time_grids =[2, 4, 5]
            for grid_id in time_grids:
                total += compute_plane_smoothness(grids[grid_id])
        return total
    def _l1_regulation(self):
                # model.grids is 6 x [1, rank * F_dim, reso, reso]
        multi_res_grids = self._deformation.deformation_net.grid.grids

        total = 0.0
        for grids in multi_res_grids:
            if len(grids) == 3:
                continue
            else:
                # These are the spatiotemporal grids
                spatiotemporal_grids = [2, 4, 5]
            for grid_id in spatiotemporal_grids:
                total += torch.abs(1 - grids[grid_id]).mean()
        return total
    def compute_regulation(self, time_smoothness_weight, l1_time_planes_weight, plane_tv_weight):
        return plane_tv_weight * self._plane_regulation() + time_smoothness_weight * self._time_regulation() + l1_time_planes_weight * self._l1_regulation()
    

    def densify_and_prune(self, max_grad, min_opacity, extent, max_screen_size):
        grads = self.xyz_gradient_accum / self.denom
        grads[grads.isnan()] = 0.0

        self.densify_and_clone(grads, max_grad, extent)
        self.densify_and_split(grads, max_grad, extent)

        prune_mask = (self.get_opacity < min_opacity).squeeze()
        if max_screen_size:
            big_points_vs = self.max_radii2D > max_screen_size
            big_points_ws = self.get_scaling.max(dim=1).values > 0.1 * extent
            prune_mask = torch.logical_or(torch.logical_or(prune_mask, big_points_vs), big_points_ws)
        self.prune_points(prune_mask)

        torch.cuda.empty_cache()