from __future__ import print_function, division
import sys
sys.path.append('core')
import argparse
import os
import cv2
import time
import numpy as np
import matplotlib.pyplot as plt
import torch
import torch.nn as nn
import torch.optim as optim
import torch.nn.functional as F
from torch.utils.data import DataLoader
from raft import RAFT
import evaluate
import datasets
from torch.utils.tensorboard import SummaryWriter
try:
from torch.cuda.amp import GradScaler
except:
# dummy GradScaler for PyTorch < 1.6
class GradScaler:
def __init__(self):
pass
def scale(self, loss):
return loss
def unscale_(self, optimizer):
pass
def step(self, optimizer):
optimizer.step()
def update(self):
pass
# exclude extremly large displacements
MAX_FLOW = 400
SUM_FREQ = 100
VAL_FREQ = 5000
def sequence_loss(flow_preds, flow_gt, valid, gamma=0.8, max_flow=MAX_FLOW):
""" Loss function defined over sequence of flow predictions """
n_predictions = len(flow_preds)
flow_loss = 0.0
# exlude invalid pixels and extremely large diplacements
mag = torch.sum(flow_gt**2, dim=1).sqrt()
valid = (valid >= 0.5) & (mag < max_flow)
for i in range(n_predictions):
i_weight = gamma**(n_predictions - i - 1)
i_loss = (flow_preds[i] - flow_gt).abs()
flow_loss += i_weight * (valid[:, None] * i_loss).mean()
epe = torch.sum((flow_preds[-1] - flow_gt)**2, dim=1).sqrt()
epe = epe.view(-1)[valid.view(-1)]
metrics = {
'epe': epe.mean().item(),
'1px': (epe < 1).float().mean().item(),
'3px': (epe < 3).float().mean().item(),
'5px': (epe < 5).float().mean().item(),
}
return flow_loss, metrics
def count_parameters(model):
return sum(p.numel() for p in model.parameters() if p.requires_grad)
def fetch_optimizer(args, model):
""" Create the optimizer and learning rate scheduler """
optimizer = optim.AdamW(model.parameters(), lr=args.lr, weight_decay=args.wdecay, eps=args.epsilon)
scheduler = optim.lr_scheduler.OneCycleLR(optimizer, args.lr, args.num_steps+100,
pct_start=0.05, cycle_momentum=False, anneal_strategy='linear')
return optimizer, scheduler
class Logger:
def __init__(self, model, scheduler):
self.model = model
self.scheduler = scheduler
self.total_steps = 0
self.running_loss = {}
self.writer = None
def _print_training_status(self):
metrics_data = [self.running_loss[k]/SUM_FREQ for k in sorted(self.running_loss.keys())]
training_str = "[{:6d}, {:10.7f}] ".format(self.total_steps+1, self.scheduler.get_last_lr()[0])
metrics_str = ("{:10.4f}, "*len(metrics_data)).format(*metrics_data)
# print the training status
print(training_str + metrics_str)
if self.writer is None:
self.writer = SummaryWriter()
for k in self.running_loss:
self.writer.add_scalar(k, self.running_loss[k]/SUM_FREQ, self.total_steps)
self.running_loss[k] = 0.0
def push(self, metrics):
self.total_steps += 1
for key in metrics:
if key not in self.running_loss:
self.running_loss[key] = 0.0
self.running_loss[key] += metrics[key]
if self.total_steps % SUM_FREQ == SUM_FREQ-1:
self._print_training_status()
self.running_loss = {}
def write_dict(self, results):
if self.writer is None:
self.writer = SummaryWriter()
for key in results:
self.writer.add_scalar(key, results[key], self.total_steps)
def close(self):
self.writer.close()
def train(args):
model = nn.DataParallel(RAFT(args), device_ids=args.gpus)
print("Parameter Count: %d" % count_parameters(model))
if args.restore_ckpt is not None:
model.load_state_dict(torch.load(args.restore_ckpt), strict=False)
model.cuda()
model.train()
if args.stage != 'chairs':
model.module.freeze_bn()
train_loader = datasets.fetch_dataloader(args)
optimizer, scheduler = fetch_optimizer(args, model)
total_steps = 0
scaler = GradScaler(enabled=args.mixed_precision)
logger = Logger(model, scheduler)
VAL_FREQ = 5000
add_noise = True
should_keep_training = True
while should_keep_training:
for i_batch, data_blob in enumerate(train_loader):
optimizer.zero_grad()
image1, image2, flow, valid = [x.cuda() for x in data_blob]
if args.add_noise:
stdv = np.random.uniform(0.0, 5.0)
image1 = (image1 + stdv * torch.randn(*image1.shape).cuda()).clamp(0.0, 255.0)
image2 = (image2 + stdv * torch.randn(*image2.shape).cuda()).clamp(0.0, 255.0)
flow_predictions = model(image1, image2, iters=args.iters)
loss, metrics = sequence_loss(flow_predictions, flow, valid, args.gamma)
scaler.scale(loss).backward()
scaler.unscale_(optimizer)
torch.nn.utils.clip_grad_norm_(model.parameters(), args.clip)
scaler.step(optimizer)
scheduler.step()
scaler.update()
logger.push(metrics)
if total_steps % VAL_FREQ == VAL_FREQ - 1:
PATH = 'checkpoints/%d_%s.pth' % (total_steps+1, args.name)
torch.save(model.state_dict(), PATH)
results = {}
for val_dataset in args.validation:
if val_dataset == 'chairs':
results.update(evaluate.validate_chairs(model.module))
elif val_dataset == 'sintel':
results.update(evaluate.validate_sintel(model.module))
elif val_dataset == 'kitti':
results.update(evaluate.validate_kitti(model.module))
logger.write_dict(results)
model.train()
if args.stage != 'chairs':
model.module.freeze_bn()
total_steps += 1
if total_steps > args.num_steps:
should_keep_training = False
break
logger.close()
PATH = 'checkpoints/%s.pth' % args.name
torch.save(model.state_dict(), PATH)
return PATH
if __name__ == '__main__':
parser = argparse.ArgumentParser()
parser.add_argument('--name', default='raft', help="name your experiment")
parser.add_argument('--stage', help="determines which dataset to use for training")
parser.add_argument('--restore_ckpt', help="restore checkpoint")
parser.add_argument('--small', action='store_true', help='use small model')
parser.add_argument('--validation', type=str, nargs='+')
parser.add_argument('--lr', type=float, default=0.00002)
parser.add_argument('--num_steps', type=int, default=100000)
parser.add_argument('--batch_size', type=int, default=6)
parser.add_argument('--image_size', type=int, nargs='+', default=[384, 512])
parser.add_argument('--gpus', type=int, nargs='+', default=[0,1])
parser.add_argument('--mixed_precision', action='store_true', help='use mixed precision')
parser.add_argument('--iters', type=int, default=12)
parser.add_argument('--wdecay', type=float, default=.00005)
parser.add_argument('--epsilon', type=float, default=1e-8)
parser.add_argument('--clip', type=float, default=1.0)
parser.add_argument('--dropout', type=float, default=0.0)
parser.add_argument('--gamma', type=float, default=0.8, help='exponential weighting')
parser.add_argument('--add_noise', action='store_true')
args = parser.parse_args()
torch.manual_seed(1234)
np.random.seed(1234)
if not os.path.isdir('checkpoints'):
os.mkdir('checkpoints')
train(args)