2025-11¶

November 30, 2025
in System
1 min read

Text mode at boot

sudo systemctl set-default multi-user.target
sudo reboot

Source: https://www.baeldung.com/linux/boot-linux-command-line-mode

November 10, 2025
in System
1 min read

Batch compress files

Batch compress files with the following tools

find : https://linux.die.net/man/1/find
GNU parallel: https://zenodo.org/records/1146014 (PDF) and https://www.gnu.org/software/parallel/parallel_tutorial.html (HTML)
7z
xz

September 12, 2025
in Code
1 min read

Julia array tips

Convert vector of vector to matrix

Use the stack function.

stack([[1,0,1],[0,0,1]], dims=1) == [ 1 0 1 ; 0 0 1 ]

Convert linear index to 2D indices

Use CartesianIndices((nrow, ncol)) ¹.

March 13, 2025
in Code
1 min read

Convert a Jupyter notebook to a literate notebook

Code adapted from JuliaInterop/NBInclude.jl

February 19, 2025
in Code
3 min read

Julia design patterns

Some notes of Tom Kwong's book Hands on Design patterns in Julia.

February 19, 2025
in Code
3 min read

Julia package loading

When your Julia codebase grows larger, you might want to organize it into modules and packages.

February 19, 2025
in Code
1 min read

Track parameter changes in simulations

From this discourse thread

Changing parameters using traditional DiffEqCallbacks.jl with prob.ps[sym] = val in the middle of a simulation cannot be tracked.

From v10, ModelingToolkit.SymbolicDiscreteCallback can track changed parameters in a callback. See https://docs.sciml.ai/ModelingToolkit/dev/basics/Events/#save_discretes

For example,

ev = ModelingToolkit.SymbolicDiscreteCallback(
    [1.0] => [iStim ~ 5],
    discrete_parameters = iStim,
    iv = t)
@mtkcompile sys = ODESystem([D(x) ~ rhs, rhs ~ -x + v_istim, v_istim ~ iStim], t; discrete_events = [ev])
prob = ODEProblem(sys, [], (0, 10.0))
@time sol = solve(prob)

February 19, 2025
in Code
10 min read

Publish Julian Jupyter notebooks

This post will demonstrate my template repositoryabout

How to use Docker to build a Julian Jupyter notebooks runtime environment.
How to use GitHub actions to execute notebooks in the docker container in parallel.
How to use jupyter-book to publish notebooks automatically when changes are pushed to GitHub.

February 19, 2025
in DevOps
1 min read

Artifacts in GitHub actions

Artifacts are data generated by workflows that can be passed to subsequent jobs.

February 19, 2025
in DevOps
2 min read

Automatic Dependency Update in GitHub

Updating package dependencies automatically as a part of continuous integration (CI).