Example #1
0
            minibatch = dataloader.next()
            imgs = minibatch['data']
            gts = minibatch['label']

            imgs = imgs.cuda(non_blocking=True)
            gts = gts.cuda(non_blocking=True)

            loss = model(imgs, gts)

            # reduce the whole loss over multi-gpu
            if engine.distributed:
                dist.all_reduce(loss, dist.ReduceOp.SUM)
                loss = loss / engine.world_size
            else:
                loss = Reduce.apply(*loss) / len(loss)

            current_idx = epoch * config.niters_per_epoch + idx
            lr = lr_policy.get_lr(current_idx)

            optimizer.param_groups[0]['lr'] = lr
            optimizer.param_groups[1]['lr'] = lr
            for i in range(2, len(optimizer.param_groups)):
                optimizer.param_groups[i]['lr'] = lr * 10

            loss.backward()
            optimizer.step()
            print_str = 'Epoch{}/{}'.format(epoch, config.nepochs) \
                        + ' Iter{}/{}:'.format(idx + 1, config.niters_per_epoch) \
                        + ' lr=%.2e' % lr \
                        + ' loss=%.2f' % loss.item()
            imgs = imgs.cuda(non_blocking=True)
            gts = gts.cuda(non_blocking=True)
            hha = hha.cuda(non_blocking=True)

            aux_rate = 0.2
            loss, loss_aux = model(imgs, hha, gts)
            tot_loss = loss + loss_aux * config.aux_rate

            # reduce the whole loss over multi-gpu
            if engine.distributed:
                dist.all_reduce(tot_loss, dist.ReduceOp.SUM)
                tot_loss = tot_loss / engine.world_size
                dist.all_reduce(loss_aux, dist.ReduceOp.SUM)
                tot_loss_aux = loss_aux / engine.world_size
            else:
                tot_loss = Reduce.apply(*tot_loss) / len(tot_loss)

            current_idx = epoch * config.niters_per_epoch + idx
            lr = lr_policy.get_lr(current_idx)

            optimizer.param_groups[0]['lr'] = lr
            optimizer.param_groups[1]['lr'] = lr
            for i in range(2, len(optimizer.param_groups)):
                optimizer.param_groups[i]['lr'] = lr

            tot_loss.backward()
            optimizer.step()
            print_str = 'Epoch{}/{}'.format(epoch, config.nepochs) \
                        + ' Iter{}/{}:'.format(idx + 1, config.niters_per_epoch) \
                        + ' lr=%.2e' % lr \
                        + ' loss=%.2f' % tot_loss.item()  \