From zero

A PhD engineer learning Python and machine learning: what to learn first and what to skip.

11 pieces, oldest first. [all series]

  1. 2025-11-16 essayColab, Jupyter or VS Code, and which one for which job What a notebook, a cell, a kernel and a virtual environment are, for an engineer who has never programmed, and what I ended up using Colab, Jupyter and VS Code for.
  2. 2025-11-19 essayStarting Python twice as an engineer who had never programmed How I started Python twice, first in a hosted notebook with nothing installed and then on my own computer where the setup took most of the effort, with the errors I hit and the order I would install things in now.
  3. 2025-11-19 essayA small neural network in plain terms What the units, layers, activation and epochs of a multilayer perceptron are, why its inputs are scaled first, and why the fit on a small table changes from one start to the next.
  4. 2025-11-25 essayTree ensembles in plain terms What a decision tree, a random forest, gradient boosting and XGBoost are, what their main settings mean, and why none of them can predict beyond the range of the runs they were trained on.
  5. 2025-11-25 essayMachine learning vocabulary in terms a process engineer already knows Twelve words from the scikit-learn workflow, each explained by a run table or a calibration curve, with the name the library gives it.
  6. 2025-11-25 essayKernel models in plain terms What a kernel is, what C, epsilon, gamma and the length scale mean in support vector regression and Gaussian process regression, why the inputs are scaled first, and what the uncertainty from a Gaussian process rests on.
  7. 2026-01-16 essayGit and GitHub for one person What commit, branch, push and .gitignore mean for one person working alone, and how I ran into each of them.
  8. 2026-02-10 essayWhat a SHAP value says and what it does not A SHAP value splits one prediction of one fitted model among its inputs, so it describes the model, and there are four common readings of the plot that it does not support.
  9. 2026-02-10 tilThe first chart to learn is predicted against actual What a parity plot is, how to draw one in matplotlib, and what to read from it that a single score does not show.
  10. 2026-02-21 tilA venv does not survive being copied to another machine I copied a Python project to a new Windows computer with its virtual environment inside, pip failed with a launcher error, and I had to delete the venv and build a new one.
  11. 2026-08-23 essayPrediction and interpretation are two different uses of a fitted model A fitted model can forecast an output or be asked which inputs it relies on, and this is the vocabulary for the second use with the limits its own documentation gives.