# Questions tagged [loss-function]

A function used to quantify the difference between observed data and predicted values according to a model. Minimization of loss functions is a way to estimate the parameters of the model.

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33 views

### Analysis of relationship between accuracy and total loss (or cost) during training with logistic loss function and threshold 0.5

I'm trying to understanding the relationship between training accuracy and training loss in classification tasks, specifically using logistic regression. When using logistic loss as the loss function ...
24 views

### Ordinal log-loss in a multiclass classification in XGBoost?

I have a multi-class problem that which classes are simultaneously mutually exclusive and have ordering. You can think of the classes as being some score: 0 (Low), 1 (Medium), 2 (High). What I would ...
22 views

### Generator loss not decreasing while training GAN

I’ve been attempting to create a basic GAN to generate images using this database of flowers (https://www.robots.ox.ac.uk/~vgg/data/flowers/102/). I’ve spent a few days on this, and largely based my ...
37 views

### Doubts on a custom loss function for regression problems

From what I read, I know we don't use log loss or cross entropy for regression problems. However, the entire logic behind binary cross entropy(say) is to firstly squeeze the y_hat between 0 and 1 (...
10 views

### Meaning of mean squared error in multistep prediction

In multistep prediction with LSTM(keras), say we had this kind of result: target = [[1,2,3] ,[4,5,6] ] predictions = [[1.1,2.2,3.3] , [4.4,5.5,6.6]] When we choose mean_squared_error as the loss ...
39 views

### Custom Loss Function Returns Graph Execution Error: Can not squeeze dim, expected a dimension of 1, got 32

I have built a loss function which adds time and frequency weighted averages and variances to the MSE: ...
15 views

### Minimize MAE loss for a target that is sum of two other targets

Working on a regression modelling task where my dataset have some feature columns, two more columns A, B and a target column T. The goal is to predict T, and minimize MAE, that is ...
49 views

### Custom loss and metric functions including additional parameter in Keras

The following example is based on this approach. Similar to that approach, I am wanting to pass an additional parameter with y_true for my custom metric, as both will be used in the computation of ...
17 views

### In the GAN objective function, why do we first do we first find the D(x) that maximizes the objective function and then maximise wrt the generator?

The GAN objective function is optimised like this: argmin(argmax(L(G,D))) where the argmax finds the D (Discriminator) that maximises L(G,D). Why is it not the other way around, i.e. argmax(argmin(L(G,...
16 views

### Cost function looks like the real math which is responsible for actually working on out problem statement If I talk on a whole and on a surface level?

Looking at the cost function for say linear regression, apart from changing the weight or the parameters, the cost function does the real job, right? If it is correct, what does cost function do in ...
9 views

### Search recall optimization - what appropriate loss function to use?

I am studying machine learning and wanted to work on a project of my own so that I have better chances after graduating college. I'm studying the application of ML to improve searches using a toy ...
27 views

### Training loss is much higher than validation loss

I am trying to train a neural network with 2 hidden layers to perform a multi class classification of 3 different classes. There is a huge imbalance to the classes, with the distribution being around ...
1 vote
16 views

### Avoid overfitting to noise by a noise penalty approach instead of early stopping?

I came across this article on deep learning for computational MRI and found an interesting sentence "However, early stopping has to be performed to not overfit to the noisy measurements." ...
37 views

### Understanding the desired behavior of the loss function of Variational Autoencoders

So I understood that when training VAE, we need to weight the KL part of the loss with a weight less than 1 so that the reconstruction loss can get a chance to learn (avoiding the posterior collapse). ...
11 views

### Loss function for classifcation rewarding closer guess?

The default loss function in multi class classification is cross_entropy, which treats all wrong guesses equally. If the distance between buckets are meaningful, for example, given the real bucket is ...
67 views

### What is the benefit of the exponential function inside softmax?

I know that softmax is: $$softmax(x) = \frac{e^{x_i}}{\sum_j^n e^{x_j}}$$ This is an $\mathbb{R}^n \implies \mathbb{R}^n$ function, and the elements of the output add up to 1. I understand that the ...
20 views

### Is there a canonical cross entropy from the confusion matrix?

In Wu, MT. Confusion matrix and minimum cross-entropy metrics based motion recognition system in the classroom. Sci Rep 12, 3095 (2022). https://doi.org/10.1038/s41598-022-07137-z the author uses a ...
86 views

### Representation of Strictly Proper Scoring Rule for Multiclasss Classificaiton

I am working on a classification problem, using features $\mathbf{x}$ to predict a target variable $y \in \mathbb{N}_0$. By a strictly proper scoring rule I mean a loss function $\ell(y,\hat{y})$ for ...
1 vote
43 views

### Replication of XGBoost's binary:logistic loss

I am trying to replicate XGBoost's logistic loss function as a first step before implementing my own custom loss functions. Following from here and looking at the original code in git repository, I ...
47 views

### Train neural network to predict multiple distributions

I aim to train a neural network to predict 2 distributions (10 quantiles, i.e. deciles) at 5 time points. So my y is of shape: ...
48 views

### Need feedback on idea for new regularization term

I've been working on creating a regularization term that ensures that correlated attributes are given similar weights in a linear model. This helps to avoid some of the inconsistency in the weights of ...
45 views

### The cost function gets stuck at 120 epochs

I did a neural network in c++ to recognize handwritten digits using the MNIST dataset without any neural network pre-existing libraries. My network has 784 inputs neuron (the pixel of the image), 100 ...
54 views

### XGBoost Architecture Diagram required

Good Day! My topic is general and theory related, about XGBoost working. I am searching XGBoost Architecture Diagram. I know it works on principles of Decision Trees, Bagging, Random Forest, Boosting, ...
47 views

### BCE loss stuck at 0.693 in the beginnng of training and then started to decrease, why?

I'm using a Transformer encoder with a binary cross entropy loss for CTR prediction. The training batch loss is at around 0.693 constantly for the beginning several thousand steps (batches). I'm using ...
44 views

### How to implement a custom loss with a non-mathematical operation (simulation) that backpropagates with PyTorch?

I am writing a Neural Network, which output is not used directly for the loss-function, but rather as the input for a simulation model. After the simulation ran, I am using the simulated_value and the ...
50 views

### Transpose of a 3D tensor

I need to transpose a 3-dimensional tensor of the shape (batch_size, N, M) to (batch_size, M, N) in a custom loss function in Keras with tensorflow as the backend. I tried using the following function ...
186 views

### How can I interpret the results of my loss functions?

I use yolov8 for object detection. The results for my training look like this: As you can see in general my validation losses are quite higher than my training losses. Here the comparison of box_loss ...
30 views

### How to select the validation loss value in this model to be compared with other models?

I'm training an LSTM model. I'm confusing about the validation loss of the model. Which value better represents the validation loss of the model? Is it the last value I obtain in the floowing loop, or ...
29 views

### Which loss function should I use if multiple values are correct?

My task is to create a QA-model. I give it a context and a question that it should answer. The answer is usually one word, so a very simplified input would be e.g. Context: "Max eats a banana. ...
28 views

### How to implement a custom loss function acting differently on multiple instances with keras?

I want to reproduce the results in "Online Neural Networks for Change-Point Detection" Hushchyn et al., but I'm having trouble implementing their loss function with Keras. The algorithm ...
1 vote
30 views

Loss function for discriminator, which needs to be maximized: -log(D(x)) + log(1-D(G(z))). Loss function for generator, which needs to be maximized: log(D(G(z))) What would the calculation of the loss ...
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### Approaching multiple records for one observation; radiomics of 2D slices of a 3D object

Background I am trying to create a model that can predict Type 2 diabetes in a patient based on MRI scans of their thigh muscle. Previous literature has shown that fat deposition in the muscle of ...
26 views

### Which is the loss function used for validating a CF Recommender System?

I am developing (from scratch) a memory-based CF Recommender System based on movielens dataset. My CF RS uses a URM (User Rating Matrix) where r_ij contains the rating the user i gave to movie j (or ...
1 vote
I have a convolutional neural network that takes an image an outputs a value between -1 and 1. If the image is an array $I$, and the network transforms the array such that \$\text{output} = f(I) \in [-...