diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..acf9ecf
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+baseline-experiments/
+synchronous/
diff --git a/arguments.py b/arguments.py
new file mode 100644
index 0000000..ef140cd
--- /dev/null
+++ b/arguments.py
@@ -0,0 +1,86 @@
+import argparse
+from typing import List
+
+parser = argparse.ArgumentParser(
+    description = "Reverse-perspective + (TransCrowd | CSRNet)"
+)
+
+# Reproducibility configuration ==============================================
+parser.add_argument(
+    "--seed", type=int, default=None, help="RNG seed"
+)
+
+# Data configuration =========================================================
+parser.add_argument(
+    "--train_dataset", type=str, default="ShanghaiA", help="Training dataset"
+)
+parser.add_argument(
+    "--test_dataset", type=str, default="ShanghaiA", help="Evaluation dataset"
+)
+parser.add_argument(
+    "--print_freq", type=int, default=1,
+    help="Print evaluation data per <print-freq> training epochs"
+)
+parser.add_argument(
+    "--start_epoch", type=int, default=0, help="Epoch to start training from"
+)
+parser.add_argument(
+    "--save_path", type=str, default="./save/default/",
+    help="Directory to save checkpoints in"
+)
+
+# Model configuration ========================================================
+parser.add_argument(
+    "--load_revnet_from", type=str, default=None,
+    help="Pre-trained reverse perspective model path"
+)
+parser.add_argument(
+    "--load_csrnet_from", type=str, default=None,
+    help="Pre-trained CSRNet model path"
+)
+parser.add_argument(
+    "--load_transcrowd_from", type=str, default=None,
+    help="Pre-trained TransCrowd model path"
+)
+
+# Optimizer configuration ====================================================
+parser.add_argument(
+    "--weight_decay", type=float, default=5e-4, help="Weight decay"
+)
+parser.add_argument(
+    "--momentum", type=float, default=0.95, help="Momentum"
+)
+parser.add_argument(
+    "--best_pred", type=float, default=1e5,
+    help="Best prediction (MAE/MSE etc.)"
+)
+
+# Performance configuration ==================================================
+parser.add_argument(
+    "--batch_size", type=int, default=8, help="Number of images per batch"
+)
+parser.add_argument(
+    "--epochs", type=int, default=250, help="Number of epochs to train"
+)
+parser.add_argument(
+    "--gpus", type=List[int], default=[0],
+    help="GPU IDs to be made available for training runtime"
+)
+
+# Runtime configuration ======================================================
+parser.add_argument(
+    "--use_ddp", type=bool, default=False,
+    help="Use DistributedDataParallel training"
+)
+parser.add_argument(
+    "--ddp_world_size", type=int, default=1,
+    help="DDP: Number of processes in Pytorch process group"
+)
+
+# nni configuration ==========================================================
+parser.add_argument(
+    "--lr", type=float, default=1e-5, help="Learning rate"
+)
+
+args     = parser.parse_args()
+ret_args = parser.parse_args()
diff --git a/eval-transcrowd.py b/eval-transcrowd.py
new file mode 100644
index 0000000..e69de29
diff --git a/model/csrnet.py b/model/csrnet.py
new file mode 100644
index 0000000..92ff779
--- /dev/null
+++ b/model/csrnet.py
@@ -0,0 +1,59 @@
+# Stolen from https://github.com/leeyeehoo/CSRNet-pytorch.git
+
+import torch.nn as nn
+import torch
+from torchvision import models
+from utils import save_net,load_net
+
+class CSRNet(nn.Module):
+    def __init__(self, load_weights=False):
+        super(CSRNet, self).__init__()
+
+        # Ref. 2018 paper
+        self.seen = 0
+        self.frontend_feat = [64, 64, 'M', 128, 128, 'M', 256, 256, 256, 'M', 512, 512, 512]
+        self.backend_feat  = [512, 512, 512, 256, 128, 64] # 4-parallel, 1, 2, 2-then-4, 4 dilation rates
+
+        self.frontend = make_layers(self.frontend_feat)
+        self.backend = make_layers(self.backend_feat,in_channels = 512,dilation = True)
+        self.output_layer = nn.Conv2d(64, 1, kernel_size=1)
+        if not load_weights:
+            mod = models.vgg16(pretrained = True)
+            self._initialize_weights()
+            for i in range(len(self.frontend.state_dict().items())):
+                self.frontend.state_dict().items()[i][1].data[:] = mod.state_dict().items()[i][1].data[:]
+
+    def forward(self,x):
+        x = self.frontend(x)
+        x = self.backend(x)
+        x = self.output_layer(x)
+        return x
+
+    def _initialize_weights(self):
+        for m in self.modules():
+            if isinstance(m, nn.Conv2d):
+                nn.init.normal_(m.weight, std=0.01)
+                if m.bias is not None:
+                    nn.init.constant_(m.bias, 0)
+            elif isinstance(m, nn.BatchNorm2d):
+                nn.init.constant_(m.weight, 1)
+                nn.init.constant_(m.bias, 0)
+
+
+def make_layers(cfg, in_channels = 3, batch_norm=False, dilation=False):
+    if dilation:
+        d_rate = 2
+    else:
+        d_rate = 1
+    layers = []
+    for v in cfg:
+        if v == 'M':
+            layers += [nn.MaxPool2d(kernel_size=2, stride=2)]
+        else:
+            conv2d = nn.Conv2d(in_channels, v, kernel_size=3, padding=d_rate, dilation=d_rate)
+            if batch_norm:
+                layers += [conv2d, nn.BatchNorm2d(v), nn.ReLU(inplace=True)]
+            else:
+                layers += [conv2d, nn.ReLU(inplace=True)]
+            in_channels = v
+    return nn.Sequential(*layers)
\ No newline at end of file
diff --git a/model/reverse_perspective.py b/model/reverse_perspective.py
index 21b2c57..c87dbae 100644
--- a/model/reverse_perspective.py
+++ b/model/reverse_perspective.py
@@ -90,7 +90,7 @@ class PerspectiveEstimator(nn.Module):
                 stride=conv_stride,
                 dilation=conv_dilation,
             ), # (N, 1, H, W)
-            'revpers_avg_pooling0': nn.AdaptiveAvgPool2d(
+            'revpers_avg_pool0': nn.AdaptiveAvgPool2d(
                 output_size=(pool_capacity, 1)
             ), # (N, 1, K, 1)
             # [?] Do we need to explicitly translate to (N, K) here?
@@ -108,7 +108,7 @@ class PerspectiveEstimator(nn.Module):
             out = layer.forward(out)
 
         # Normalize in (0, 1]
-        F.relu_(out) # in-place
+        F.relu(out, inplace=True)
         out = torch.exp(-out) + self.epsilon
 
         return out
@@ -116,4 +116,47 @@ class PerspectiveEstimator(nn.Module):
     # def unsupervised_loss(predictions, targets):
 
 # [TODO] We need a modified loss -- one that takes advantage of attention instead
-# of feature map. I feel like they should work likewise but who knows
\ No newline at end of file
+# of feature map. I feel like they should work likewise but who knows
+# [XXX] no forget it, we are pre-training rev-perspective as told by the 2020 paper
+# i.e., via using CSRNet.
+# Not sure which part is the feature map derived. Maybe after the front-end?
+# In any case we can always just use the CSR output (inferred density map) as feature map --
+# through which we compute, for each image:
+# criterion = Variance([output.sum(axis=W) * effective_pixel_per_row])
+# In other cases we sum over channels i.e., each feature map i.e., over each filter output
+# Not sure what channel means in this case...
+def warped_output_loss(csrnet_pred):
+    N, H, W = csrnet_pred.shape()
+
+
+def transform_coordinates(
+        img: torch.Tensor,      # (C, W, H)
+        factor: float,
+        in_place: bool = True
+):
+    dev_of_img = img.device
+
+    # Normalize X coords to [0, pi]
+    min_x = torch.Tensor([0., 0., 0.]).to(dev_of_img)
+    max_x = torch.Tensor([0., np.pi, 0.]).to(dev_of_img)
+    min_xdim = torch.min(img, dim=1, keepdim=True)[0]
+    max_xdim = torch.max(img, dim=1, keepdim=True)[0]
+    (img.sub_(min_xdim)
+        .div_(max_xdim - min_xdim)
+        .mul_(max_x - min_x)
+        .add_(min_x))
+
+    # Normalize Y coords to [0, 1]
+    min_y = torch.Tensor([0., 0., 0.]).to(dev_of_img)
+    max_y = torch.Tensor([0., 1., 0.]).to(dev_of_img)
+    min_ydim = torch.min(img, dim=2, keepdim=True)[0]
+    max_ydim = torch.max(img, dim=2, keepdim=True)[0]
+    (img.sub_(min_ydim)
+        .div_(max_ydim - min_ydim)
+        .mul_(max_y - min_y)
+        .add_(min_y))
+
+    # Do elliptical transformation
+    tmp = img.clone().detach()
+    
+    pass
\ No newline at end of file
diff --git a/model/revpers_csrnet.py b/model/revpers_csrnet.py
new file mode 100644
index 0000000..e69de29
diff --git a/model/stn.py b/model/stn.py
new file mode 100644
index 0000000..e1e7199
--- /dev/null
+++ b/model/stn.py
@@ -0,0 +1,204 @@
+# stole from pytorch tutorial
+import torch
+import torch.nn as nn
+import torch.nn.functional as F
+import torch.optim as optim
+import torchvision
+from torchvision import datasets, transforms
+import matplotlib.pyplot as plt
+import numpy as np
+
+class StnNet(nn.Module):
+    def __init__(self, input_size: torch.Size):
+        super(StnNet, self).__init__()
+
+        # Sanity check
+        assert 5 > len(input_size) > 2  # single or batch ([N, ]C, H, W)
+        if len(input_size) == 3:
+            channels, height, width = input_size
+        else:
+            channels, height, width = input_size[1:]
+
+        self.conv1 = nn.Conv2d(1, 10, kernel_size=5)
+        self.conv2 = nn.Conv2d(10, 20, kernel_size=5)
+        self.conv2_drop = nn.Dropout2d()
+        self.fc1 = nn.Linear(320, 50)
+        self.fc2 = nn.Linear(50, 10)
+
+        # Spatial transformer localization-network
+        self.localization_net = nn.Sequential(      # (N, C, H, W)
+            nn.Conv2d(channels, 8, kernel_size=7),  # (N, 8, H-6, W-6)
+            nn.MaxPool2d(2, stride=2),              # (N, 8, (H-6)/2, (W-6)/2)
+            nn.ReLU(True),
+            nn.Conv2d(8, 10, kernel_size=5),        # (N, 10, ((H-6)/2)-4, ((W-6)/2)-4)
+            nn.MaxPool2d(2, stride=2),              # (N, 10, (((H-6)/2)-4)/2, (((H-6)/2)-4)/2)
+            nn.ReLU(True)
+        ) # -> (N, 10, (((H-6)/2)-4)/2, (((H-6)/2)-4)/2)
+        self._loc_net_out_shape = (
+            10,
+            (((height - 6) // 2) - 4) // 2,
+            (((width - 6) // 2) - 4) // 2
+        ) # TODO: PLEASE let me know if there are better ways of doing this...
+
+        # Regressor for the 3 * 2 affine matrix
+        self.fc_loc = nn.Sequential(
+            nn.Linear(np.prod(self._loc_net_out_shape), 32),
+            nn.ReLU(True),
+            nn.Linear(32, 3 * 2)
+        )  # -> (6,)
+
+        # Initialize the weights/bias with identity transformation
+        self.fc_loc[2].weight.data.zero_()
+        self.fc_loc[2].bias.data.copy_(
+            torch.tensor(
+                [1, 0, 0,
+                 0, 1, 0],
+                dtype=torch.float
+            )
+        )
+
+    # Spatial transformer network forward function
+    def stn(self, x):
+        xs = self.localization_net(x)
+        xs = xs.view(-1, np.prod(self._loc_net_out_shape))  # -> (N, whatever)
+        theta = self.fc_loc(xs)
+        theta = theta.view(-1, 2, 3)                        # -> (2, 3)
+
+        grid = F.affine_grid(theta, x.size())
+        x = F.grid_sample(x, grid)
+
+        return x
+
+    def forward(self, x):
+        # transform the input
+        x = self.stn(x)
+
+        # Perform the usual forward pass
+        x = F.relu(F.max_pool2d(self.conv1(x), 2))
+        x = F.relu(F.max_pool2d(self.conv2_drop(self.conv2(x)), 2))
+        x = x.view(-1, 320)
+        x = F.relu(self.fc1(x))
+        x = F.dropout(x, training=self.training)
+        x = self.fc2(x)
+        return F.log_softmax(x, dim=1)
+
+if __name__ == "__main__":
+    device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
+    train_loader = torch.utils.data.DataLoader(
+        dataset=datasets.MNIST(
+            root="./synchronous/",
+            train=True,
+            download=True,
+            transform=transforms.Compose([
+                transforms.ToTensor(),
+                transforms.Normalize((.1307, ), (.3081, ))
+            ]),
+        ),
+        batch_size=64,
+        shuffle=True,
+        num_workers=4,
+    )
+    valid_loader = torch.utils.data.DataLoader(
+        dataset=datasets.MNIST(
+            root = "./synchronous/",
+            train=False,
+            transform=transforms.Compose([
+                transforms.ToTensor(),
+                transforms.Normalize((.1307, ), (.3081, ))
+            ]),
+        ),
+        batch_size=64,
+        shuffle=True,
+        num_workers=4,
+    )
+    shape_of_input = next(iter(train_loader))[0].shape
+    model = StnNet(shape_of_input).to(device)
+    optimizer = optim.SGD(model.parameters(), lr=.01)
+    def train(epoch):
+        model.train()
+        for i, (x_, t_) in enumerate(train_loader):
+            # XXX: x_.shape == (N, C, H, W)
+            # Inference
+            x_, t_ = x_.to(device), t_.to(device)
+            optimizer.zero_grad()
+            y_ = model(x_)
+            # Backprop
+            l_ = F.nll_loss(y_, t_)
+            l_.backward()
+            optimizer.step()
+            if i % 500 == 0:
+                print("Epoch {}: [{}/{} ({:.0f}%)]\tLoss: {:.6f}".format(
+                    epoch,
+                    i * len(x_),
+                    len(train_loader.dataset),
+                    100. * i / len(train_loader),
+                    l_.item()
+                ))
+
+    def valid():
+        with torch.no_grad():
+            model.eval()
+            valid_loss = 0
+            correct = 0
+            for x_, t_ in valid_loader:
+                x_, t_ = x_.to(device), t_.to(device)
+                y_ = model(x_)
+                # Sum batch loss
+                valid_loss += F.nll_loss(y_, t_, size_average=False).item()
+                pred = y_.max(1, keepdim=True)[1]
+                correct += pred.eq(t_.view_as(pred)).sum().item()
+
+            valid_loss /= len(valid_loader.dataset)
+            print("\nValid set: Avg. loss: {:.4f}, Accuracy: {}/{} ({:.0f}%)\n"
+                .format(
+                    valid_loss, correct, len(valid_loader.dataset),
+                    100. * correct / len(valid_loader.dataset)
+                )
+            )
+
+    def convert_image_np(inp):
+        """Convert a Tensor to numpy image."""
+        inp = inp.numpy().transpose((1, 2, 0))
+        mean = np.array([0.485, 0.456, 0.406])
+        std = np.array([0.229, 0.224, 0.225])
+        inp = std * inp + mean
+        inp = np.clip(inp, 0, 1)
+        return inp
+
+    # We want to visualize the output of the spatial transformers layer
+    # after the training, we visualize a batch of input images and
+    # the corresponding transformed batch using STN.
+    def visualize_stn():
+        with torch.no_grad():
+            # Get a batch of training data
+            data = next(iter(test_loader))[0].to(device)
+
+            input_tensor = data.cpu()
+            transformed_input_tensor = model.stn(data).cpu()
+
+            in_grid = convert_image_np(
+                torchvision.utils.make_grid(input_tensor))
+
+            out_grid = convert_image_np(
+                torchvision.utils.make_grid(transformed_input_tensor))
+
+            # Plot the results side-by-side
+            f, axarr = plt.subplots(1, 2)
+            axarr[0].imshow(in_grid)
+            axarr[0].set_title('Dataset Images')
+
+            axarr[1].imshow(out_grid)
+            axarr[1].set_title('Transformed Images')
+
+    for epoch in range(1, 20 + 1):
+        train(epoch)
+        valid()
+
+    # Visualize the STN transformation on some input batch
+    visualize_stn()
+
+    plt.ioff()
+    plt.show()
+
+
+
diff --git a/train-revpers.py b/train-revpers.py
new file mode 100644
index 0000000..b9a29b4
--- /dev/null
+++ b/train-revpers.py
@@ -0,0 +1,101 @@
+from argparse import Namespace
+
+import timm
+import torch
+import torch.multiprocessing as torch_mp
+from torch.utils.data import DataLoader
+import nni
+import logging
+
+from model.csrnet import CSRNet
+from model.reverse_perspective import PerspectiveEstimator
+from arguments import args, ret_args
+
+logger = logging.getLogger("train-revpers")
+
+# We use 2 separate networks as opposed to 1 whole network --
+# this is more flexible, as we only train one of them...
+def gen_csrnet(pth_tar: str = None) -> CSRNet:
+    if pth_tar is not None:
+        model = CSRNet(load_weights=True)
+        checkpoint = torch.load(pth_tar)
+        model.load_state_dict(checkpoint["state_dict"], strict=False)
+    else:
+        model = CSRNet(load_weights=False)
+    return model
+
+def gen_revpers(pth_tar: str = None, **kwargs) -> PerspectiveEstimator:
+    model = PerspectiveEstimator(**kwargs)
+    if pth_tar is not None:
+        checkpoint = torch.load(pth_tar)
+        model.load_state_dict(checkpoint["state_dict"], strict=False)
+    return model
+
+def build_train_loader():
+    pass
+
+def build_valid_loader():
+    pass
+
+def train_one_epoch(
+        train_loader: DataLoader,
+        revpers_net: PerspectiveEstimator,
+        csr_net: CSRNet,
+        criterion,
+        optimizer,
+        scheduler,
+        epoch: int,
+        args: Namespace
+):
+    # Get learning rate
+    curr_lr = optimizer.param_groups[0]["lr"]
+    print("Epoch %d, processed %d samples, lr %.10f" %
+        (epoch, epoch * len(train_loader.dataset), curr_lr)
+    )
+
+    # Set to train mode (perspective estimator only)
+    revpers_net.train()
+    end = time.time()
+
+    # In one epoch, for each training sample
+    for i, (fname, img, gt_count) in enumerate(train_loader):
+        # fpass (revpers)
+        img = img.cuda()
+        out_revpers = revpers_net(img)
+        # We need to perform image transformation here...
+        
+        img = img.cpu()
+
+        # fpass (csrnet -- do not train)
+        img = img.cuda()
+        out_csrnet = csr_net(img)
+        # loss wrt revpers
+        loss = criterion()
+
+
+    pass
+
+def valid_one_epoch():
+    pass
+
+def main(rank: int, args: Namespace):
+    pass
+
+if __name__ == "__main__":
+    tuner_params = nni.get_next_parameter()
+    logger.debug("Generated hyperparameters: {}", tuner_params)
+    combined_params = Namespace(
+        nni.utils.merge_parameter(ret_args, tuner_params)
+    ) # Namespaces have better ergonomics, notably a struct-like access syntax.
+    logger.debug("Parameters: {}", combined_params)
+
+    if combined_params.use_ddp:
+        # Use DDP, spawn threads
+        torch_mp.spawn(
+            main,
+            args=(combined_params, ), # rank supplied automatically as 1st param
+            nprocs=combined_params.world_size,
+        )
+    else:
+        # No DDP, run in current thread
+        main(None, combined_params)
\ No newline at end of file
diff --git a/transform_img.py b/transform_img.py
new file mode 100644
index 0000000..c6d711e
--- /dev/null
+++ b/transform_img.py
@@ -0,0 +1,6 @@
+# If we cannot get revpersnet running,
+# we still ought to do some sort of information-preserving perspective transformation
+# e.g., randomized transformation
+# and let transcrowd to crunch through these transformed image instead.
+# After training, we obtain the attention map and put it in our paper.
+# I just want to get things done...
\ No newline at end of file