Merge branch 'data_parallel' into data_parallel_py3.8

# Conflicts:
#	models/model.py
#	utils/configuration.py
#	utils/triplet_loss.py

7 files changed, 211 insertions, 88 deletions

diff --git a/config.py b/config.py
index 03f2f0d..e1ee2fb 100644
--- a/config.py
+++ b/config.py
@@ -5,7 +5,7 @@ config: Configuration = {
         # Disable accelerator
         'disable_acc': False,
         # GPU(s) used in training or testing if available
-        'CUDA_VISIBLE_DEVICES': '0',
+        'CUDA_VISIBLE_DEVICES': '0,1',
         # Directory used in training or testing for temporary storage
         'save_dir': 'runs',
         # Recorde disentangled image or not
@@ -30,14 +30,14 @@ config: Configuration = {
         # Resolution after resize, can be divided 16
         'frame_size': (64, 48),
         # Cache dataset or not
-        'cache_on': False,
+        'cache_on': True,
     },
     # Dataloader settings
     'dataloader': {
         # Batch size (pr, k)
         # `pr` denotes number of persons
         # `k` denotes number of sequences per person
-        'batch_size': (4, 6),
+        'batch_size': (6, 8),
         # Number of workers of Dataloader
         'num_workers': 4,
         # Faster data transfer from RAM to GPU if enabled
@@ -53,7 +53,7 @@ config: Configuration = {
             # Use 1x1 convolution in dimensionality reduction
             'hpm_use_1x1conv': False,
             # HPM pyramid scales, of which sum is number of parts
-            'hpm_scales': (1, 2, 4),
+            'hpm_scales': (1, 2, 4, 8),
             # Global pooling method
             'hpm_use_avg_pool': True,
             'hpm_use_max_pool': True,
@@ -63,13 +63,15 @@ config: Configuration = {
             'tfa_num_parts': 16,
             # Embedding dimension for each part
             'embedding_dims': 256,
-            # Triplet loss margins for HPM and PartNet
-            'triplet_margins': (1.5, 1.5),
+            # Batch Hard or Batch All
+            'triplet_is_hard': True,
+            # Use non-zero mean or sum
+            'triplet_is_mean': True,
+            # Triplet loss margins for HPM and PartNet, None for soft margin
+            'triplet_margins': None,
         },
         'optimizer': {
             # Global parameters
-            # Iteration start to optimize non-disentangling parts
-            # 'start_iter': 0,
             # Initial learning rate of Adam Optimizer
             'lr': 1e-4,
             # Coefficients used for computing running averages of
@@ -83,15 +85,15 @@ config: Configuration = {
             # 'amsgrad': False,
 
             # Local parameters (override global ones)
-            # 'auto_encoder': {
-            #     'weight_decay': 0.001
-            # },
+            'auto_encoder': {
+                'weight_decay': 0.001
+            },
         },
         'scheduler': {
-            # Period of learning rate decay
-            'step_size': 500,
-            # Multiplicative factor of decay
-            'gamma': 1,
+            # Step start to decay
+            'start_step': 15_000,
+            # Multiplicative factor of decay in the end
+            'final_gamma': 0.001,
         }
     },
     # Model metadata
@@ -105,6 +107,6 @@ config: Configuration = {
         # Restoration iteration (multiple models, e.g. nm, bg and cl)
         'restore_iters': (0, 0, 0),
         # Total iteration for training (multiple models)
-        'total_iters': (80_000, 80_000, 80_000),
+        'total_iters': (25_000, 25_000, 25_000),
     },
 }
diff --git a/models/layers.py b/models/layers.py
index ae61583..e30d0c4 100644
--- a/models/layers.py
+++ b/models/layers.py
@@ -80,7 +80,9 @@ class DCGANConvTranspose2d(BasicConvTranspose2d):
         if self.is_last_layer:
             return self.trans_conv(x)
         else:
-            return super().forward(x)
+            x = self.trans_conv(x)
+            x = self.bn(x)
+            return F.leaky_relu(x, 0.2, inplace=True)
 
 
 class BasicLinear(nn.Module):
diff --git a/models/model.py b/models/model.py
index 2c72270..46d7c4c 100644
--- a/models/model.py
+++ b/models/model.py
@@ -18,7 +18,7 @@ from utils.configuration import DataloaderConfiguration, \
     SystemConfiguration
 from utils.dataset import CASIAB, ClipConditions, ClipViews, ClipClasses
 from utils.sampler import TripletSampler
-from utils.triplet_loss import JointBatchAllTripletLoss
+from utils.triplet_loss import JointBatchTripletLoss, BatchTripletLoss
 
 
 class Model:
@@ -68,7 +68,7 @@ class Model:
         self._dataset_sig: str = 'undefined'
 
         self.rgb_pn: Optional[RGBPartNet] = None
-        self.ba_triplet_loss: Optional[JointBatchAllTripletLoss] = None
+        self.triplet_loss: Optional[JointBatchTripletLoss] = None
         self.optimizer: Optional[optim.Adam] = None
         self.scheduler: Optional[optim.lr_scheduler.StepLR] = None
         self.writer: Optional[SummaryWriter] = None
@@ -143,9 +143,10 @@ class Model:
         dataloader = self._parse_dataloader_config(dataset, dataloader_config)
         # Prepare for model, optimizer and scheduler
         model_hp: Dict = self.hp.get('model', {}).copy()
-        triplet_margins = model_hp.pop('triplet_margins', (0.2, 0.2))
+        triplet_is_hard = model_hp.pop('triplet_is_hard', True)
+        triplet_is_mean = model_hp.pop('triplet_is_mean', True)
+        triplet_margins = model_hp.pop('triplet_margins', None)
         optim_hp: Dict = self.hp.get('optimizer', {}).copy()
-        start_iter = optim_hp.pop('start_iter', 0)
         ae_optim_hp = optim_hp.pop('auto_encoder', {})
         pn_optim_hp = optim_hp.pop('part_net', {})
         hpm_optim_hp = optim_hp.pop('hpm', {})
@@ -153,28 +154,48 @@ class Model:
         sched_hp = self.hp.get('scheduler', {})
         self.rgb_pn = RGBPartNet(self.in_channels, self.in_size, **model_hp,
                                  image_log_on=self.image_log_on)
-        self.ba_triplet_loss = JointBatchAllTripletLoss(
-            self.rgb_pn.hpm_num_parts, triplet_margins
-        )
+        # Hard margins
+        if triplet_margins:
+            # Same margins
+            if triplet_margins[0] == triplet_margins[1]:
+                self.triplet_loss = BatchTripletLoss(
+                    triplet_is_hard, triplet_margins[0]
+                )
+            else:  # Different margins
+                self.triplet_loss = JointBatchTripletLoss(
+                    self.rgb_pn.hpm_num_parts,
+                    triplet_is_hard, triplet_is_mean, triplet_margins
+                )
+        else:  # Soft margins
+            self.triplet_loss = BatchTripletLoss(
+                triplet_is_hard, triplet_is_mean, None
+            )
+
+        num_pairs = (self.pr*self.k-1) * (self.pr*self.k) // 2
+        num_pos_pairs = (self.k*(self.k-1)//2) * self.pr
+
         # Try to accelerate computation using CUDA or others
         self.rgb_pn = nn.DataParallel(self.rgb_pn)
         self.rgb_pn = self.rgb_pn.to(self.device)
-        self.ba_triplet_loss = nn.DataParallel(self.ba_triplet_loss)
-        self.ba_triplet_loss = self.ba_triplet_loss.to(self.device)
+        self.triplet_loss = nn.DataParallel(self.triplet_loss)
+        self.triplet_loss = self.triplet_loss.to(self.device)
         self.optimizer = optim.Adam([
             {'params': self.rgb_pn.module.ae.parameters(), **ae_optim_hp},
             {'params': self.rgb_pn.module.pn.parameters(), **pn_optim_hp},
             {'params': self.rgb_pn.module.hpm.parameters(), **hpm_optim_hp},
             {'params': self.rgb_pn.module.fc_mat, **fc_optim_hp}
         ], **optim_hp)
-        sched_gamma = sched_hp.get('gamma', 0.9)
-        sched_step_size = sched_hp.get('step_size', 500)
+        sched_final_gamma = sched_hp.get('final_gamma', 0.001)
+        sched_start_step = sched_hp.get('start_step', 15_000)
+
+        def lr_lambda(epoch):
+            passed_step = epoch - sched_start_step
+            all_step = self.total_iter - sched_start_step
+            return sched_final_gamma ** (passed_step / all_step)
         self.scheduler = optim.lr_scheduler.LambdaLR(self.optimizer, lr_lambda=[
-            lambda epoch: sched_gamma ** (epoch // sched_step_size),
-            lambda epoch: 0 if epoch < start_iter else 1,
-            lambda epoch: 0 if epoch < start_iter else 1,
-            lambda epoch: 0 if epoch < start_iter else 1,
+            lr_lambda, lr_lambda, lr_lambda, lr_lambda
         ])
+
         self.writer = SummaryWriter(self._log_name)
 
         self.rgb_pn.train()
@@ -194,7 +215,7 @@ class Model:
         running_loss = torch.zeros(5, device=self.device)
         print(f"{'Time':^8} {'Iter':^5} {'Loss':^6}",
               f"{'Xrecon':^8} {'CanoCons':^8} {'PoseSim':^8}",
-              f"{'BATripH':^8} {'BATripP':^8} {'LRs':^19}")
+              f"{'BATripH':^8} {'BATripP':^8} {'LR':^9}")
         for (batch_c1, batch_c2) in dataloader:
             self.curr_iter += 1
             # Zero the parameter gradients
@@ -202,16 +223,16 @@ class Model:
             # forward + backward + optimize
             x_c1 = batch_c1['clip'].to(self.device)
             x_c2 = batch_c2['clip'].to(self.device)
-            feature, ae_losses, images = self.rgb_pn(x_c1, x_c2)
+            embedding, ae_losses, images = self.rgb_pn(x_c1, x_c2)
             y = batch_c1['label'].to(self.device)
             # Duplicate labels for each part
             y = y.repeat(self.rgb_pn.num_total_parts, 1)
-            triplet_loss = self.ba_triplet_loss(feature, y)
+            trip_loss, dist, num_non_zero = self.triplet_loss(embedding, y)
             losses = torch.cat((
                 ae_losses.mean(0),
                 torch.stack((
-                    triplet_loss[:self.rgb_pn.hpm_num_parts].mean(),
-                    triplet_loss[self.rgb_pn.hpm_num_parts:].mean()
+                    trip_loss[:self.rgb_pn.hpm_num_parts].mean(),
+                    trip_loss[self.rgb_pn.hpm_num_parts:].mean()
                 ))
             ))
             loss = losses.sum()
@@ -222,20 +243,50 @@ class Model:
             running_loss += losses.detach()
             # Write losses to TensorBoard
             self.writer.add_scalar('Loss/all', loss, self.curr_iter)
-            self.writer.add_scalars('Loss/details', dict(zip([
+            self.writer.add_scalars('Loss/disentanglement', dict(zip((
                 'Cross reconstruction loss', 'Canonical consistency loss',
-                'Pose similarity loss', 'Batch All triplet loss (HPM)',
-                'Batch All triplet loss (PartNet)'
-            ], losses)), self.curr_iter)
+                'Pose similarity loss'
+            ), ae_losses)), self.curr_iter)
+            self.writer.add_scalars('Loss/triplet loss', {
+                'HPM': losses[3],
+                'PartNet': losses[4]
+            }, self.curr_iter)
+            # None-zero losses in batch
+            if num_non_zero is not None:
+                self.writer.add_scalars('Loss/non-zero counts', {
+                    'HPM': num_non_zero[:self.rgb_pn.hpm_num_parts].mean(),
+                    'PartNet': num_non_zero[self.rgb_pn.hpm_num_parts:].mean()
+                }, self.curr_iter)
+            # Embedding distance
+            mean_hpm_dist = dist[:self.rgb_pn.hpm_num_parts].mean(0)
+            self._add_ranked_scalars(
+                'Embedding/HPM distance', mean_hpm_dist,
+                num_pos_pairs, num_pairs, self.curr_iter
+            )
+            mean_pa_dist = dist[self.rgb_pn.hpm_num_parts:].mean(0)
+            self._add_ranked_scalars(
+                'Embedding/ParNet distance', mean_pa_dist,
+                num_pos_pairs, num_pairs, self.curr_iter
+            )
+            # Embedding norm
+            mean_hpm_embedding = embedding[:self.rgb_pn.hpm_num_parts].mean(0)
+            mean_hpm_norm = mean_hpm_embedding.norm(dim=-1)
+            self._add_ranked_scalars(
+                'Embedding/HPM norm', mean_hpm_norm,
+                self.k, self.pr * self.k, self.curr_iter
+            )
+            mean_pa_embedding = embedding[self.rgb_pn.hpm_num_parts:].mean(0)
+            mean_pa_norm = mean_pa_embedding.norm(dim=-1)
+            self._add_ranked_scalars(
+                'Embedding/PartNet norm', mean_pa_norm,
+                self.k, self.pr * self.k, self.curr_iter
+            )
 
             if self.curr_iter % 100 == 0:
                 lrs = self.scheduler.get_last_lr()
                 # Write learning rates
                 self.writer.add_scalar(
-                    'Learning rate/Auto-encoder', lrs[0], self.curr_iter
-                )
-                self.writer.add_scalar(
-                    'Learning rate/Others', lrs[1], self.curr_iter
+                    'Learning rate', lrs[0], self.curr_iter
                 )
                 # Write disentangled images
                 if self.image_log_on:
@@ -259,7 +310,7 @@ class Model:
                 print(f'{hour:02}:{minute:02}:{second:02}',
                       f'{self.curr_iter:5d} {running_loss.sum() / 100:6.3f}',
                       '{:f} {:f} {:f} {:f} {:f}'.format(*running_loss / 100),
-                      '{:.3e} {:.3e}'.format(lrs[0], lrs[1]))
+                      f'{lrs[0]:.3e}')
                 running_loss.zero_()
 
             # Step scheduler
@@ -278,6 +329,24 @@ class Model:
                 self.writer.close()
                 break
 
+    def _add_ranked_scalars(
+            self,
+            main_tag: str,
+            metric: torch.Tensor,
+            num_pos: int,
+            num_all: int,
+            global_step: int
+    ):
+        rank = metric.argsort()
+        pos_ile = 100 - (num_pos - 1) * 100 // num_all
+        self.writer.add_scalars(main_tag, {
+            '0%-ile': metric[rank[-1]],
+            f'{100 - pos_ile}%-ile': metric[rank[-num_pos]],
+            '50%-ile': metric[rank[num_all // 2 - 1]],
+            f'{pos_ile}%-ile': metric[rank[num_pos - 1]],
+            '100%-ile': metric[rank[0]]
+        }, global_step)
+
     def predict_all(
             self,
             iters: Tuple[int],
@@ -317,6 +386,8 @@ class Model:
 
         # Init models
         model_hp: Dict = self.hp.get('model', {}).copy()
+        model_hp.pop('triplet_is_hard', True)
+        model_hp.pop('triplet_is_mean', True)
         model_hp.pop('triplet_margins', None)
         self.rgb_pn = RGBPartNet(self.in_channels, self.in_size, **model_hp)
         # Try to accelerate computation using CUDA or others
diff --git a/models/rgb_part_net.py b/models/rgb_part_net.py
index 4d7ba7f..310ef25 100644
--- a/models/rgb_part_net.py
+++ b/models/rgb_part_net.py
@@ -81,7 +81,7 @@ class RGBPartNet(nn.Module):
             ((f_a_, f_c_, f_p_), losses) = self.ae(x_c1_t2, x_c1_t1, x_c2_t2)
             # Decode features
             x_c = self._decode_cano_feature(f_c_, n, t, device)
-            x_p_ = self._decode_pose_feature(f_p_, n, t, c, h, w, device)
+            x_p_ = self._decode_pose_feature(f_p_, n, t, device)
             x_p = x_p_.view(n, t, self.pn_in_channels, self.h // 4, self.w // 4)
 
             i_a, i_c, i_p = None, None, None
@@ -100,7 +100,7 @@ class RGBPartNet(nn.Module):
         else:  # evaluating
             f_c_, f_p_ = self.ae(x_c1_t2)
             x_c = self._decode_cano_feature(f_c_, n, t, device)
-            x_p_ = self._decode_pose_feature(f_p_, n, t, c, h, w, device)
+            x_p_ = self._decode_pose_feature(f_p_, n, t, device)
             x_p = x_p_.view(n, t, self.pn_in_channels, self.h // 4, self.w // 4)
             return (x_c, x_p), None, None
 
@@ -125,7 +125,7 @@ class RGBPartNet(nn.Module):
         )
         return x_c
 
-    def _decode_pose_feature(self, f_p_, n, t, c, h, w, device):
+    def _decode_pose_feature(self, f_p_, n, t, device):
         # Decode pose features to images
         x_p_ = self.ae.decoder(
             torch.zeros((n * t, self.f_a_dim), device=device),
diff --git a/requirements.txt b/requirements.txt
index 4d30e17..926a587 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,6 +1,6 @@
 torch~=1.7.1
 torchvision~=0.8.0a0+ecf4e9c
 numpy~=1.19.4
-tqdm~=4.57.0
+tqdm~=4.58.0
 Pillow~=8.1.0
 scikit-learn~=0.24.0
\ No newline at end of file
diff --git a/utils/configuration.py b/utils/configuration.py
index b9e6d92..376ae0f 100644
--- a/utils/configuration.py
+++ b/utils/configuration.py
@@ -43,6 +43,8 @@ class ModelHPConfiguration(TypedDict):
     tfa_squeeze_ratio: int
     tfa_num_parts: int
     embedding_dims: int
+    triplet_is_hard: bool
+    triplet_is_mean: bool
     triplet_margins: Tuple[float, float]
 
 
@@ -55,7 +57,6 @@ class SubOptimizerHPConfiguration(TypedDict):
 
 
 class OptimizerHPConfiguration(TypedDict):
-    start_iter: int
     lr: int
     betas: Tuple[float, float]
     eps: float
@@ -68,8 +69,8 @@ class OptimizerHPConfiguration(TypedDict):
 
 
 class SchedulerHPConfiguration(TypedDict):
-    step_size: int
-    gamma: float
+    start_step: int
+    final_gamma: float
 
 
 class HyperparameterConfiguration(TypedDict):
diff --git a/utils/triplet_loss.py b/utils/triplet_loss.py
index 6025bd3..ae899ec 100644
--- a/utils/triplet_loss.py
+++ b/utils/triplet_loss.py
@@ -1,34 +1,48 @@
-from typing import Tuple
+from typing import Optional, Tuple
 
 import torch
 import torch.nn as nn
 import torch.nn.functional as F
 
 
-class BatchAllTripletLoss(nn.Module):
-    def __init__(self, margin: float = 0.2):
+class BatchTripletLoss(nn.Module):
+    def __init__(
+            self,
+            is_hard: bool = True,
+            is_mean: bool = True,
+            margin: Optional[float] = 0.2,
+    ):
         super().__init__()
+        self.is_hard = is_hard
+        self.is_mean = is_mean
         self.margin = margin
 
     def forward(self, x, y):
         p, n, c = x.size()
-
         dist = self._batch_distance(x)
-        positive_negative_dist = self._hard_distance(dist, y, p, n)
-        all_loss = F.relu(self.margin + positive_negative_dist).view(p, -1)
-        parted_loss_mean = self._none_zero_parted_mean(all_loss)
-
-        return parted_loss_mean
-
-    @staticmethod
-    def _hard_distance(dist, y, p, n):
-        hard_positive_mask = y.unsqueeze(1) == y.unsqueeze(2)
-        hard_negative_mask = y.unsqueeze(1) != y.unsqueeze(2)
-        all_hard_positive = dist[hard_positive_mask].view(p, n, -1, 1)
-        all_hard_negative = dist[hard_negative_mask].view(p, n, 1, -1)
-        positive_negative_dist = all_hard_positive - all_hard_negative
-
-        return positive_negative_dist
+        flat_dist_mask = torch.tril_indices(n, n, offset=-1, device=dist.device)
+        flat_dist = dist[:, flat_dist_mask[0], flat_dist_mask[1]]
+
+        if self.is_hard:
+            positive_negative_dist = self._hard_distance(dist, y, p, n)
+        else:  # is_all
+            positive_negative_dist = self._all_distance(dist, y, p, n)
+
+        if self.margin:
+            losses = F.relu(self.margin + positive_negative_dist).view(p, -1)
+            non_zero_counts = (losses != 0).sum(1).float()
+            if self.is_mean:
+                loss_metric = self._none_zero_mean(losses, non_zero_counts)
+            else:  # is_sum
+                loss_metric = losses.sum(1)
+            return loss_metric, flat_dist, non_zero_counts
+        else:  # Soft margin
+            losses = F.softplus(positive_negative_dist).view(p, -1)
+            if self.is_mean:
+                loss_metric = losses.mean(1)
+            else:  # is_sum
+                loss_metric = losses.sum(1)
+            return loss_metric, flat_dist, None
 
     @staticmethod
     def _batch_distance(x):
@@ -40,41 +54,74 @@ class BatchAllTripletLoss(nn.Module):
         dist = torch.sqrt(
             F.relu(x1_squared_sum - 2 * x1_times_x2_sum + x2_squared_sum)
         )
-
         return dist
 
     @staticmethod
-    def _none_zero_parted_mean(all_loss):
-        # Non-zero parted mean
-        non_zero_counts = (all_loss != 0).sum(1)
-        parted_loss_mean = all_loss.sum(1) / non_zero_counts
-        parted_loss_mean[non_zero_counts == 0] = 0
+    def _hard_distance(dist, y, p, n):
+        positive_mask = y.unsqueeze(1) == y.unsqueeze(2)
+        negative_mask = y.unsqueeze(1) != y.unsqueeze(2)
+        hard_positive = dist[positive_mask].view(p, n, -1).max(-1).values
+        hard_negative = dist[negative_mask].view(p, n, -1).min(-1).values
+        positive_negative_dist = hard_positive - hard_negative
+
+        return positive_negative_dist
+
+    @staticmethod
+    def _all_distance(dist, y, p, n):
+        # Unmask identical samples
+        positive_mask = torch.eye(
+            n, dtype=torch.bool, device=y.device
+        ) ^ (y.unsqueeze(1) == y.unsqueeze(2))
+        negative_mask = y.unsqueeze(1) != y.unsqueeze(2)
+        all_positive = dist[positive_mask].view(p, n, -1, 1)
+        all_negative = dist[negative_mask].view(p, n, 1, -1)
+        positive_negative_dist = all_positive - all_negative
 
-        return parted_loss_mean
+        return positive_negative_dist
+
+    @staticmethod
+    def _none_zero_mean(losses, non_zero_counts):
+        # Non-zero parted mean
+        non_zero_mean = losses.sum(1) / non_zero_counts
+        non_zero_mean[non_zero_counts == 0] = 0
+        return non_zero_mean
 
 
-class JointBatchAllTripletLoss(BatchAllTripletLoss):
+class JointBatchTripletLoss(BatchTripletLoss):
     def __init__(
             self,
             hpm_num_parts: int,
+            is_hard: bool = True,
+            is_mean: bool = True,
             margins: Tuple[float, float] = (0.2, 0.2)
     ):
-        super().__init__()
+        super().__init__(is_hard, is_mean)
         self.hpm_num_parts = hpm_num_parts
         self.margin_hpm, self.margin_pn = margins
 
     def forward(self, x, y):
         p, n, c = x.size()
-
         dist = self._batch_distance(x)
-        positive_negative_dist = self._hard_distance(dist, y, p, n)
+        flat_dist_mask = torch.tril_indices(n, n, offset=-1, device=dist.device)
+        flat_dist = dist[:, flat_dist_mask[0], flat_dist_mask[1]]
+
+        if self.is_hard:
+            positive_negative_dist = self._hard_distance(dist, y, p, n)
+        else:  # is_all
+            positive_negative_dist = self._all_distance(dist, y, p, n)
+
         hpm_part_loss = F.relu(
             self.margin_hpm + positive_negative_dist[:self.hpm_num_parts]
-        ).view(self.hpm_num_parts, -1)
+        )
         pn_part_loss = F.relu(
             self.margin_pn + positive_negative_dist[self.hpm_num_parts:]
-        ).view(p - self.hpm_num_parts, -1)
-        all_loss = torch.cat((hpm_part_loss, pn_part_loss)).view(p, -1)
-        parted_loss_mean = self._none_zero_parted_mean(all_loss)
+        )
+        losses = torch.cat((hpm_part_loss, pn_part_loss)).view(p, -1)
+
+        non_zero_counts = (losses != 0).sum(1).float()
+        if self.is_mean:
+            loss_metric = self._none_zero_mean(losses, non_zero_counts)
+        else:  # is_sum
+            loss_metric = losses.sum(1)
 
-        return parted_loss_mean
+        return loss_metric, flat_dist, non_zero_counts