# Regression task to predict a point in space

i’m trying to do a vision regression task where i’m trying to detect a point in space (the image) based on the location of my character.

Thing is my accuracy is always 0, I’m unsure what I’m doing wrong.
This is my first time trying to write my own PyTorch task, did I do a mistake, or is the model not strong enough?

Structure of my data

Basically I’m trying to predict x,y based on image, which I will use it as a point.

But whatever I tried, my model can’t converge, I don’t care about test data yet etc, just trying to learn step by step things.

Here is my code

``````from cgitb import grey
from unittest import skip
from torchvision import datasets, transforms
from torch.utils.data import DataLoader,Dataset
import torch
import torch.nn as nn
import numpy as np
import matplotlib.pyplot as plt
import pandas as pd
import numpy as np
import cv2 as cv
%matplotlib inline

device = "cuda" if torch.cuda.is_available() else "cpu"

# ## Data

class Dataset(Dataset):

def __init__(self):
self.data = np.loadtxt('data.csv', delimiter=',', dtype=str)

def __getitem__(self, index):
img_resized = cv.resize(img, (400,400), interpolation = cv.INTER_AREA)

gray = cv.cvtColor(img_resized, cv.COLOR_BGR2GRAY)
gray = (gray / 255)
gray = torch.tensor(gray).float()

x1 = torch.tensor([float(self.data[index,1])], dtype=torch.float)
x2 = torch.tensor([float(self.data[index,2])], dtype=torch.float)
x1 = (x1 / 1.89) / 400  # normalizing data to be between 0-1
x2 = (x2 / 1.25) / 400 # normalizing data to be between 0-1

return gray,x1,x2

def __len__(self):
return len(self.data)

dataset = Dataset()

class Model(nn.Module):
def __init__(self):
super(Model, self).__init__()
self.fc1 = nn.Linear(400*400, 1024)
self.relu = nn.ReLU()
self.fc2 = nn.Linear(1024, 1024)
self.fc3 = nn.Linear(1024, 2)
self.sigmoid = nn.Sigmoid()

def forward(self, x):
x = x.view(-1, 400*400)
x = self.fc1(x)
x = self.relu(x)
x = self.fc2(x)
x = self.relu(x)
x = self.fc3(x)
x = sigmoid(x)

return x

model = Model()
model.to(device)

loss_fn = nn.MSELoss()
optimizer = torch.optim.Adam(model.parameters(), lr=0.001)

EPOCH = 200

loss_total = []

model.train()
for epoch in range(EPOCH):
correct = 0
loss_list = 0

correct = 0
for i, (img, x1,x2) in enumerate(train_loader):
img = img.to(device)

x1 = x1.to(device)
x2 = x2.to(device)

y_pred = model(img)

loss = loss_fn(y_pred, torch.stack(x1,x2))
loss.backward()
optimizer.step()

loss_list += loss.item()

correct += (y_pred == torch.stack(x1,x2)).sum().item()

if i % 32 == 0:

print(f"Epoch: {epoch}, Step: {i}, Loss: {loss / 32} , Correct: {(correct/32) * 100}%")
loss_total.append(loss / 32)

plt.plot(np.linspace(1, EPOCH, EPOCH).astype(int), loss_total)

``````

As you see the model has no cnn, or anything special, I’m trying to play around with normal NN then go up, I’m learning from a book and trying to apply what I learn on my own data.
Thank you

I am not sure if it makes any difference. But there seems to be a typo in which `x2` is not considered at all?

Those were typos when I was transferring the code here… my original code on vs code has them correct, edited the post. Sorry for confusion

Another straightforward bug: Floating point numbers cannot be compared with `==`.
Maybe use `torch.isclose()` with appropriate tolerance?

https://pytorch.org/docs/stable/generated/torch.isclose.html

Hello,

Some points that might have caused this issue:

• Your model’s output layer has a sigmoid in the end. This means the model will output only between [0 - 1] which generally is not desired in a regression task.
• Accuracy is an incorrect measure when you are evaluating a regression task, you should look into
• Mean Squared Error (MSE).
• Root Mean Squared Error (RMSE).
• Mean Absolute Error (MAE)

I hope this helps Thanks so much for the tips!