Generate synthetic mixtures from pure spectra
A Python script to generate random synthetic mixtures from pure spectra from a database. This post can be used as a tutorial to generate datasets for Multivariate Curve Resolution.
Category: Regression
Diagnostic plots for linear regression
A short survey of diagnostic plots, as tools to dig deeper on the assumptions behind a regression model.
Genetic algorithm for wavelength selection using Numpy
Regression, Partial Least Squares Regression, Variable Selection
06/22/2024
A implementation of a genetic algorithm for wavelength selection using basic Numpy functions.
Wavelength selection with a genetic algorithm
Wavelength selection methods aim at choosing the spectral bands that produce the best regression or classification model. Here we introduce a genetic algorithm for wavelength selection.
Updates and additions to the PLS Regression code
Regression, Partial Least Squares Regression, Plots and Charts
04/29/2023
Updated code and additional utility scripts for PLS regression. Will keep it updated as we go.
Multivariate curve resolution: an introduction
Multivariate Curve Resolution deals with spectra, or other signals, from samples containing multiple components, and aims at recovering the pure components.
Understanding neural network parameters with TensorFlow in Python: the optimiser
Neural Networks, Regression
11/20/2022
An introductory tutorial on optimisers for deep learning, including Python code for a regression training for NIR spectroscopy.
Regression optimisation with a Pipeline
The process of developing and optimising a regression model, almost invariably requires a sequence of steps. These steps can be combined in a single predictor using the Pipeline function …
Parallel computation of loops for cross-validation analysis
Using parallel computation to speed up cross-validation analysis for large data sets.
Understanding neural network parameters with TensorFlow in Python: the activation function
Neural Networks, Regression
04/09/2022
Where we discuss the meaning of an activation function in neural networks, discuss a few examples, and show a comparison of neural network training with different activation functions.
Deep neural networks for spectral data regression with TensorFlow
Neural Networks, Regression
03/12/2022
This post introduces basic Python code to build fully-connected deep neural networks with TensorFlow for regression analysis of spectral data.
The Akaike Information Criterion for model selection
The Akaike Information Criterion (AIC) is another tool to compare prediction models. AIC combines model accuracy and parsimony in a single metric and can be used to evaluate data …
Minimal prediction models for linear regression
Regression
04/10/2021
What is the minimum amount of information required to export and re-use a linear regression model? The answer is surprisingly simple. Here's a step by step example using PLS …
Backward Variable Selection for PLS regression
Regression, Partial Least Squares Regression
03/13/2021
Backward Variable Selection for PLS regression is a method to discard variables that contribute poorly to the regression model. Here's a Python implementation of the method.
The Concordance Correlation Coefficient
Regression, Regression metrics, Regression Model Validation
01/09/2021
The Concordance Correlation Coefficient (CCC) can be useful to quantify the quality of a linear regression model. In this tutorial we explain the CCC and describe its relation with …
Bias-Variance trade-off in PLS regression
Bias-Variance trade-off refers to the optimal choice of parameters in a model in order to avoid both overfitting and underfitting. Let's look at a worked example using PLS regression.
Wavelength band selection with simulated annealing
Regression, Partial Least Squares Regression
08/15/2020
Improve the performance of a PLS method by wavelength band selection using Simulated Annealing optimisation.
Principal component selection with simulated annealing
Principal Components Regression, Regression
02/09/2020
Simulated annealing helps overcome some of the shortcomings of greedy algorithms. Here's a tutorial on simulated annealing for principal components selection in regression.
Principal component selection with a greedy algorithm
Principal Components Regression, Regression
01/28/2020
Greedy algorithms are commonly used to optimise a function over a parameter space. Here's an implementation of a greedy algorithm for principal components selection in regression.
Moving window PLS regression
Regression, Partial Least Squares Regression
12/07/2019
Not all wavelengths are created equals. A moving window PLS algorithm optimises the regression by discarding bands that are not useful for prediction.
K-fold and Montecarlo cross-validation vs Bootstrap: a primer
Cross-validation is a standard procedure to quantify the robustness of a regression model. Compare K-Fold, Montecarlo and Bootstrap methods and learn some neat trick in the process.
Principal Component Regression in Python revisited
Principal Components Regression, Regression
09/10/2019
Want to get more out of your principal components regression? Here's a simple hack that will give you a stunning improvement on the performance of PCR.
Principal Components Regression vs Ridge Regression on NIR data in Python
Principal Components Regression, Regression, Ridge Regression
10/19/2018
Principal components regression is a staple of NIR analysis. Ridge regression is much used of machine learning. How do they relate? Find out in this post.
Outliers detection with PLS regression for NIR spectroscopy in Python
Not every data point is created equal. In this post we'll show how to perform outliers detection with PLS regression for NIR spectroscopy in Python.
A variable selection method for PLS in Python
Improve the quality of your PLS regression using variable selection. This tutorial will work through a variable selection method for PLS in Python.
Partial Least Squares Regression in Python
Partial Least Squares Regression, Regression
06/14/2018
Step by step tutorial on how to build a NIR calibration model using Partial Least Squares Regression in Python.
Principal Component Regression in Python
Principal Components Regression, Regression
05/12/2018
An in-depth introduction to Principal Component Regression in Python using NIR data. PCR is the combination of PCA with linear regression. Check it out.
