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Charles Jekel

Engineer. Regression. Optimization.

cj@jekel.me

  • Dec 04, 2021
    Ellipsoid Non-linear Regression Fitting

    How to fit an ellipsoid to data points using non-linear regression. Included is a simple Python example using JAX.

  • Sep 20, 2020
    Least Squares Ellipsoid Fit

    How to fit an ellipsoid to data points using the least squares method with a simple Python example.

  • Jan 30, 2020
    Better error bars with tolerance intervals

    Plotting the mean and standard deviation is not enough when you only have a few replicate samples.

  • Apr 28, 2019
    Compare lstsq performance in Python

    Comparing the performance of the least-squares solvers in NumPy, CuPy, and TensorFlow.

  • Apr 15, 2019
    Adding TensorFlow support for pwlf

    New pwlf 0.5.0 release has introduced a lot of changes. This post will focus on the newly added TensorFlow support. A benchmark is provided to compare the performance of the new TensorFlow class against the original Numpy/SciPy class.

  • Mar 12, 2019
    Attempting to detect the number of important line segments in data

    Many people using pwlf want to find out how many line segments are present in their data. There is an expensive way to do this, but this posts attempts to find some cheaper alternatives. A least squares fit and an Elastic Net are used to help identify important breakpoint locations.

  • Dec 03, 2018
    Using the validate function to compare different FaceNet models in tindetheus

    Comparing different facenet models on a hot-or-not dataset using the new validate function in tindetheus.

  • Sep 18, 2018
    Battery and screen replacement on a LeEco Le Max 2 (x2)

    I just replaced my battery and screen on my LeEco Le Max 2 and took pictures of the entire process.

  • Jul 29, 2018
    Visual Studio Code Python Setup

    Visual Studio Code is my favorite editor, and it's particular useful for working with Python. This post shows how to setup Code so that you can start writing better Python!

  • Apr 17, 2018
    512 vs 128 FaceNet embeddings on Tinder dataset

    Comparing the new 512 embedding facenet models with the old 128 embedding models on my Tinder dataset.

  • Apr 15, 2018
    Force piecewise linear fit through data

    Now you can use pwlf to force a fit through any set of data points! This is done as a constrained least squares problem.

  • Apr 08, 2018
    pwlf update: fitting continuous piecewise linear models to data

    New derivation used in pwlf library for fitting continuous piecewise linear functions to data.

  • Mar 28, 2018
    Using facenet to automatically review Tinder profiles

    I used facenet to find a pattern in the Tinder profiles I liked and disliked. This post explains how I did it.

  • Feb 04, 2018
    Using tmpfs to speed up non-linear finite element models

    Benchmark of a HDD, SSD, and tmpfs (RAM disk) for read/write, and behncmark of an optimization on a non-linear FE model.

  • Jan 02, 2018
    Tindetheus: automatically like users on Tinder based on your own preference - How to install on Windows 10

    Tindetheus makes it easy for a user to build and apply their own personalized machine learning model on Tinder. These models can be used to automatically like or dislike users, and take advantage of recent developments in computer vision to find a pattern in the faces you find attractive. The post goes on to describe how to install tindetheus on a Windows 10 PC.

  • Dec 24, 2017
    Computers I've assembled

    I've assembled a few computers throughout the years. Here is a list of the CPUs I've used and the year assembled for each of the computers I've put together.

  • Sep 27, 2017
    Comparison of performance: Python NumPy and Numba, MATLAB, and Fortran

    The time it takes to perform an array operation is compared in Python NumPy, Python NumPy with Numba accleration, MATLAB, and Fortran. The arrays are large, with one million to one billion elements. Numba is a great choice for parallel acceleration of Python and NumPy.

  • Jul 02, 2017
    Comparing measures of similarity between curves

    There are many different metrics that can be minimized to determine how similar two different curves are. This post looks at fitting a line to data points by minimizing different metrics of similarity. A least squares optimization is done which minimizes the sum-of-squares. The traditional least squares fit is compared to minimizing the discrete Fréchet distance, the dynamic time warping (DTW) distance, and my own area metric.

  • May 01, 2017
    Detect faces using facenet in Python

    The TensorFlow implementation of facenet is an extremely powerful deep face recognition library. You can download pre-trained models with a LFW accuracy of 0.993. This post demonstrates how you can use the facenet library to detect faces in images using Python.

  • Apr 01, 2017
    Fitting a piecewise linear function to data

    A Python library to fit continuous piecewise linear functions to data was created. This library allows for the user to specify the desired number of line segments when fitting piecewise linear functions.

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