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The Python square root function, sqrt(), is part of the math module and is used to calculate the square root of a given number. To use it, you import the math module and call math.sqrt() with a non-negative number as an argument. For example, math.sqrt(9) returns 3.0.

This function works with both integers and floats and is essential for mathematical operations like solving equations and calculating geometric properties. In this tutorial, you’ll learn how to effectively use the square root function in Python.

By the end of this tutorial, you’ll understand how:

• Python’s sqrt() function calculates square roots using Python’s math.sqrt() for quick and accurate results in your programs.
• math.sqrt() calculates the square root of positive numbers and zero but raises an error for negative inputs.
• Python’s square root function can be used to solve real-world problems like calculating distances using the Pythagorean theorem.

Time to dive in!

Python Pit Stop: This tutorial is a quick and practical way to find the info you need, so you’ll be back to your project in no time!

Free Bonus: Click here to get our free Python Cheat Sheet that shows you the basics of Python 3, like working with data types, dictionaries, lists, and Python functions.

Square Roots in Mathematics

In algebra, a square, x, is the result of a number, n, multiplied by itself: x = n²

You can calculate squares using Python:

Python >>> n = 5 >>> x = n**2 >>> x 25 Copied!

The Python ** operator is used for calculating the power of a number. In this case, 5 squared, or 5 to the power of 2, is 25.

The square root, then, is the number n, which when multiplied by itself yields the square, x.

In this example, n, the square root of 25, is 5.

25 is an example of a perfect square. Perfect squares are the squares of integer values:

Python >>> 1**2 1 >>> 2**2 4 >>> 3**2 9 Copied!

You might have memorized some of these perfect squares when you learned your multiplication tables in an elementary algebra class.

If you’re given a small perfect square, it may be straightforward enough to calculate or memorize its square root. But for most other squares, this calculation can get a bit more tedious. Often, an estimation is good enough when you don’t have a calculator.

Read the full article at https://realpython.com/python-square-root-function/ »

[ Improve Your Python With 🐍 Python Tricks 💌 – Get a short & sweet Python Trick delivered to your inbox every couple of days. >> Click here to learn more and see examples ]

Since WFDF changed their ultimate rules web site to be less-than-ideal (in the name of putting everything into Wordpress…), I made my own, at urules.org. It was a fun journey; I've never fiddled with PWAs before, and I was a bit surprised how low-level it all was. I assumed that since my page is just a bunch of HTML files and ~100 lines of JS, I could just bundle that up—but no, that is something they expect a framework to do for you.

The only primitive you get is seemingly that you can fire up your own background service worker (JS running in its own, locked-down context) and that gets to peek at every HTTP request done and possibly intercept it. So you can use a Web Cache (seemingly a separate concept from web local storage?), insert stuff into that, and then query it to intercept requests. It doesn't feel very elegant, perhaps?

It is a bit neat that I can use this to make my own bundling, though. All the pages and images (painfully converted to SVG to save space and re-flow for mobile screens, mostly by simply drawing over bitmaps by hand in Inkscape) are stuck into a JSON dictionary, compressed using the slowest compressor I could find and then downloaded as a single 159 kB bundle. It makes the site actually sort of weird to navigate; since it pretty quickly downloads the bundle in the background, everything goes offline and the speed of loading new pages just feels… off somehow. As if it's not a Serious Web Page if there's no load time.

Of course, this also means that I couldn't cache PNGs, because have you ever tried to have non-UTF-8 data in a JSON sent through N layers of JavaScript? :-)

Another short status update of what happened on my side last month. Besides a phosh bugfix release improving text input and selection was a prevalent pattern again resulting in improvements in the compositor, the OSK and some apps.

phosh

• Install gir (MR). Needed for e.g. Debian to properly package the Rust bindings.
• Try harder to find an app icon when showing notifications (MR)
• Add a simple Pomodoro timer plugin (MR)
• Small screenshot manager fixes (MR)
• Tweak portals configuration (MR)
• Consistent focus style on lock screen and settings (MR). Improves the visual appearance as the dotted focus frame doesn't match our otherwise colored focus frames
• Don't focus buttons in settings (MR). Improves the visual appearance as attention isn't drawn to the button focus.
• Close Phosh's settings when activating a Settings panel (MR)

phoc

• Improve cursor and cursor theme handling, hide mouse pointer by default (MR)
• Don't submit empty preedit (MR)
• Fix flickering selection bubbles in GTK4's text input fields (MR)
• Backport two more fixes and release 0.41.1 (MR)

phosh-mobile-settings

• Allow to select default text completer (MR, MR)
• Don't crash when we fail to load a pref plugin (MR)

libphosh-rs

• Update with current gir and allow to use status pages (MR)
• Expose screenshot manager and build without warnings (MR). (Improved further by a follow up MR from Sam)
• Fix clippy warnings and add clippy to CI (MR)

phosh-osk-stub

• presage: Always set predictors (MR). Avoids surprises with unwanted predictors.
• Install completer information (MR)
• Handle overlapping touch events (MR). This should improve fast typing.
• Allow plain ctrl and alt in the shortcuts bar (MR
• Use Adwaita background color to make the OSK look more integrated (MR)
• Use StyleManager to support accent colors (MR)
• Fix emoji section selection in RTL locales (MR)
• Don't submit empty preedit (MR). Helps to better preserve text selections.

phosh-osk-data

• Add scripts to build word corpus from Wikipedia data (MR) See here for the data.

xdg-desktop-portal-phosh

• Release 0.42~rc1 (MR)
• Fix HighContrast (MR)

Debian

• Collect some of the QCom workarounds in a package (MR). This is not meant to go into Debian proper but it's nicer than doing all the mods by hand and forgetting which files were modified.
• q6voiced: Fix service configuration (MR)
• chatty: Enable clock test again (MR), and then unbreak translations (MR)
• phosh: Ship gir for libphosh-rs (MR)
• phoc: Backport input method related fix (MR)
• Upload initial package of phosh-osk-data: Status in NEW
• Upload initial package of xdg-desktop-portal-pohsh: Status in NEW
• Backport phosh-osk-stub abbrev fix (MR
• phoc: Update to 0.42.1 (MR
• mobile-tweaks: Enable zram on Librem 5 and PP (MR)

ModemManager

• Some further work on the Cell Broadcast to address comments MR)

Calls

• Further improve daemon mode (MR) (mentioned last month already but got even simpler)

GTK

• Handle Gtk{H,V}Separator when migrating UI files to GTK4 (MR)

feedbackd

• Modernize README a bit (MR)

Chatty

• Use special event for SMS (MR)
• Another QoL fix when using OSK (MR)
• Fix printing time diffs on 32bit architectures (MR)

libcmatrix

• Use endpoints for authenticated media (MR). Needed to support v1.11 servers.

phosh-ev

• Switch to GNOME 47 runtime (MR)

git-buildpackage

• Don't use deprecated pkg-resources (MR)

Unified push specification

• Expand on DBus activation a bit (MR)

swipeGuess

• Small build improvement and mention phosh-osk-stub (Commit)

wlr-clients

• Fix -o option and add help output (MR)

iotas (Note taking app)

• Don't take focus with header bar buttons (MR). Makes typing faster (as the OSK won't hide) and thus using the header bar easier

Flare (Signal app)

• Don't take focus when sending messages, adding emojis or attachments (MR). Makes typing faster (as the OSK won't hide) and thus using those buttons easier

xdg-desktop-portal

• Use categories that work for both xdg-spec and the portal (MR)

Reviews

This is not code by me but reviews on other peoples code. The list is fairly incomplete, hope to improve on this in the upcoming months:

• phosh-tour: add first login mode (MR)
• phosh: Animate swipe closing notifications (MR)
• iio-sensor-proxy: Report correct value on claim (MR)
• iio-sensor-proxy: face-{up,down} (MR)
• phosh-mobile-settings: Squeekboad scaling (MR)
• libcmatrix: Misc cleanups/fixes (MR)
• phosh: Notification separator improvements (MR
• phosh: Accent colors (MR

Help Development

If you want to support my work see donations. This includes a list of hardware we want to improve support for. Thanks a lot to all current and past donors.

Doing more swimming in everyday life for the past few months. Seems like I am keeping that up.

Dolphin's accessibility, Itinerary's travelling aids, and a bunch of new upcoming KDE apps

Welcome to a new issue of "This Week in KDE Apps"! Every week we cover as much as possible of what's happening in the world of KDE apps.

In this issue we discover what developers have been doing to make Dolphin, KDE's most popular (but not only!) file explorer, more accessible. We also take a look at all the new services now integrated into Itinerary that will help you on your travels, the new features for Kate that programmers will enjoy, improvements to Kleopatra to help you manage your certificates and the encryption of your messages, and the flurry of new applications that will soon be available in KDE's software catalog.

This week, we also kicked off our 2024 end-of-year fundraiser just in time for Halloween! Any monetary contribution, however small, will help us cover operational costs, salaries, travel expenses for contributors and in general just keep KDE bringing Free Software to the world. So consider doing a donation today!

Let's dig in!

Dolphin Manage your files

We improved the keyboard navigation of Dolphin, as pressing Ctrl+L multiple times will switch back and forth between focusing and selecting the location bar path and focusing the view. Pressing Escape in the location bar, will now move the focus to the active view (Felix Ernst, 24.12.0. Link).

Speaking of accessibility, the accessibility of the main view of Dolphin was completely overhauled to make it work with screen readers. This work was funded by NGI0 Entrust Fund, a fund established by NLnet with financial support from the European Commission's Next Generation Internet programme (Felix Ernst, 24.12.0. Link).

Another change is that Dolphin will now store its view properties inside the extended file attributes instead of creating hidden .directory files when possible (Méven Car, 24.12.0. Link).

digiKam Photo Management Program

digiKam is KDE's powerful photo management software for both professional and aficionado photographers.

Michael Miller fixed an issue where faces from the facial recognition feature were not deleted when a user untagged or deleted a face (Michael Miller. Link).

Elisa Play music and listen to online radio stations

Jack Hill fixed a few issues related to the lyrics feature. Clicking on the Lyrics button now takes you to the correct lyric and not the previous one, and the last line of the lyrics is not displayed completely (Jack Hill, 24.12.0. Link).

Jack also reworked the metadata dialogs to be more intuitive and correct some bugs (Jack Hill, 24.12.0. Link).

GCompris Educational game for children

GCompris, the educational software suite, got a new activity: Sketch! This fun tool lets children express their creativity and draw beautiful artworks (Timothée Giet. Link).

KDE Itinerary Digital travel assistant

Itinerary now supports extracting reservations from planway.com, flight tickets from VietJet Air and train tickets from the Thai state railway. Additionally, dates from day-specific train tickets from NS (Nederlandse Spoorwegen) are now correctly parsed (Volker Krause, 24.08.3. Link 1, link 2, link 3), and, while on an NS intercity train, you can also access the live journey information provided by the onboard WiFi (Carl Schwan, 24.12.0. Link).

Kate Advanced Text Editor

Kate continues to become more and more developer friendly with the changes made by Christoph Cullmann where the order of the tabs is correctly restored when restoring a previous session (Christoph Cullmann, 24.08.3. Link), and the options of the LSP Symbols are more easily discoverable as they are not only available via a context menu, but also within a menu button at the top (Waqar Ahmed, 24.12.0. Link).

Benjamin Port fixed the Appium UI tests and reenabled them on the CI (Benjamin Port, 28.03.0. Link).

Kdenlive Video editor

Kdenlive is KDE's full-featured video editor, which now lets you resize multiple items on the timeline at the same time. (Jean-Baptiste Mardelle, 24.12.0 Link).

Kleopatra Certificate manager and cryptography app

We redesigned Kleopatra's notepad and sign encrypt dialog. In the notepad, the text editor and the recipients view are also now side by side (Carl Schwan, 24.12.0. Link).

Additionally, Tobias worked on the notepad's result messages and error dialogs to make them clearer. (Tobias Fella, 24.12.0 Link 1, link 2).

Tobias also fixed a crash on non-kwin Wayland compositors (Tobias Fella, 24.08.3. Link), and Kleopatra has a new website (Carl Schwan. Link).

Kongress Conference companion

Kongress is an app which helps you navigate conferences and events.

The newest version will display more information about events in the event list. This includes whether the event is in your bookmarked events and the locations within the event (e.g. the rooms) (cah fof pai, 24.12.0. Link).

Speaking of conferences, multiple KDE people will be at the Chaos Communication Congress (38c3) in Hamburg this December! Come by and say hello!

KStars Desktop Planetarium

KStars is KDE's stargazing app that also helps you control your telescope for astrophotography.

We removed the "Simulate Eyepiece View" feature and stripped down EyepieceField. The reason is the offerings of the eyepiece view feature have already been superseded by two more powerful and easier-to-use features in KStars: the HiPS Overlay and the "Views" feature (Akarsh Simha, 3.7.4. Link).

Kwave Sound editor

Mark Penner wrote a blog post about his work on KWave.

LabPlot Interactive Data Visualization and Analysis

LabPlot is KDE's complete suite of data analysis and visualisation tools.

The LabPlot developers added the RAND_MAX programming constants for GSL (GNU Scientific Library) support. (Martin Marmsoler Link), and rewrote the AsciiFilter to increase the parsing speed, like when parsing livedata from an mqtt feed (Martin Marmsoler. Link).

Kuntal Bar also fixed various issues with HiDPI screens (Kuntal Bar, Link).

Marknote Write down your thoughts

Marknote lets you create rich text notes and easily organise them into notebooks.

The icons in the app are now correctly displayed when running Marknote on other platforms, like Windows (Gary Wang, Link).

Ruqola Rocket Chat Client

Ruqola, KDE's Rocket Chat client, received various fixes for its login, logout and network disconnection features (David Faure & Andras Mantia Link 1, link 2, link 3 and link 4), and the unread message bar now uses buttons instead of more subtle links (Joshua Goins. Link).

Spectacle Screenshot Capture Utility

Spectacle is the utility for taking screenshots and screencasts of your desktop and apps. We fixed an issue where Spectacle would take a screenshot of itself (Noah Davis, 24.08.3. Link).

Other Stuff

The FormCard components used by most Kirigami application are now more compact on the desktop (Carl Schwan, Kirigami Addons 1.6.0 Link).

Before After

The About Page provided by the FormCard component now displays more information about the components used by the application (e.g. Qt, KDE Frameworks) (Carl Schwan, Kirigami Addons 1.6.0. Link).

Playground

This section contains news about non released applications.

Arkade

Arkade, a collection of games written in QML, was updated to Qt6 (Carl Schwan. Link).

Whale

Claudio Cambra ported Whale, a QML based file manager and explorer, to Qt6 (Claudio Cambra. Link). Claudio also added a miller columns view to Whale (Claudio Cambra. Link), and implemented navigation history (Claudio Cambra. Link).

And all this too...

Justin Zobel fixed various appstream files to use the new way of declaring the developer's name (Justin Zobel, KRuler, Gwenview, KEuroCalc, ...).

We ported various projects to use declarative QML declaration for better maintainance and performance (Carl Schwan, Koko, Francis, Kalk).

... And Everything Else

This blog only covers the tip of the iceberg! If you’re hungry for more, check out Nate's blog about Plasma and be sure not to miss his This Week in Plasma series, where every Saturday he covers all the work being put into KDE's Plasma desktop environment.

For a complete overview of what's going on, visit KDE's Planet, where you can find all KDE news unfiltered directly from our contributors.

Get Involved

The KDE organization has become important in the world, and your time and contributions have helped us get there. As we grow, we're going to need your support for KDE to become sustainable.

You can help KDE by becoming an active community member and getting involved. Each contributor makes a huge difference in KDE — you are not a number or a cog in a machine! You don’t have to be a programmer either. There are many things you can do: you can help hunt and confirm bugs, even maybe solve them; contribute designs for wallpapers, web pages, icons and app interfaces; translate messages and menu items into your own language; promote KDE in your local community; and a ton more things.

You can also help us by donating. Any monetary contribution, however small, will help us cover operational costs, salaries, travel expenses for contributors and in general just keep KDE bringing Free Software to the world.

To get your application mentioned here, please ping us in invent or in Matrix.

Best wishes to the entire Debian and Free Software world for a happy and prosperous Gujarati New Year Vikram Samvat 2081 named Anala.

A fun fact: Although Diwali was on Thursday, because it was a vrddha tithi (a lunar day that spans more than one sunrise,) there was a leap day and that's why the new year didn't start till today.

I haven't posted to this blog for almost exactly three years. I had decided that I wasn't going to until I revamped the blog engine to force myself to actually do it and still managed to drag my feet for this long. This post was supposed to be the first public test of the new version but something has gone unexpectedly gone wrong so this is actually a manually uploaded placeholder until I figure out what happened. I have been regularly taking part in the Perl & Raku Weekly Challenge and I write a little about my solutions with yet another half-finished blog engine.

What else have I been up to? Not a lot Debianwise. I voted a couple of times, sponsored a package and (hopefully) assisted one person in becoming a Debian developer. There's the challenge I mentioned which atleast gets me writing some Perl and Raku every week. I did the 7DRL Game Jam again this year and actually produced a playable game. It needs to be polished though (and open sourced.)

This is my major problem; I have all kinds of things which I've started and left incomplete. It's time to do something about it. In the coming months I am going to do a comprehensive review of all the bits of software I've written or contributed to and either complete them, clean them up or properly abandon them. I shall call this Project 2025.

For the last year I’ve been working as a team lead for backend API development with Gigaclear a UK rural ISP who own and run fibre internet to rural communities across the UK. This is alongside my training work.

This image shows the main project I’ve been working on since joining Gigaclear, One Touch Switch. A regulatory requirement for all ISPs to allow automated switching between ISPs. When you sign up with a new internet provider your account is automatically ceased with the old provider and VOIP numbers can be automatically ported.

Our OTS project is just part of the Gigaclear One Touch Switch system which interfaces with Salesforce and Netadmin and the website order flow (the Online Buying Journey) and represents an impressive engineering effort. We were one of the first ISPs with a system ready to take part in industry trials a few months ago, both OTS and our underlying systems passed pen testing with flying colours, and the switch on has been smooth.

Something I’m proud to have been part of. My current project is preparing security awareness training materials based on OWASP for our various engineering departments whilst we also undertake a systematic review of all of our systems and processes.

In the diagram I’m team lead for the Sphinx engineering team.

My first blog post in a few years! I have some articles I’d like to publish, and some adventures to share, so I thought it was time to fire up a blog engine again.

My nine year old son, Benjamin, is really into programming with Scratch and he’s keen to play with electronics and learn MicroPython. Which is awesome because there’s almost nothing I would love to do more with him.

MicroPython is an extremely impressive implementation of Python that will run on embedded devices and microcontrollers, as well as bigger tiny computers like the Raspberry Pi.

I’ve dug out an old MicroBit I had, purchased a Raspberry Pi Pico board/kit and also a ZumoBot 2040 robot which uses the same microcontroller as the Pico, to play with.

I’m now starting to get to grips with the basics, using the Thonny IDE.

I have a bunch of Neopixel LEDs, including a long light strip, I’d like to wire up in my living room controlled by a Pico board and an Android App using Kivy. That’s my goal number 1.

I’d like to program the ZumoBot to explore and map my flat. Goal 2.

Meanwhile Benjamin is enjoying playing with electronics (switches, LEDs, potentiometer and now a motor) with the Pico and on his own he’s programming the MicroBit with Scratch (or at least “blocks” which is the Microsoft equivalent). I’ve also done my first soldering in over a decade.

I have a github repository to track my tinkering, but I’d like to write up some recipes and post them on this blog as I go. (The biggest hurdle is I can’t easily create circuit diagrams. Time to explore.)

The github repository and ZumoBot links:

• https://github.com/voidspace/zumobot
• https://thepihut.com/products/zumo-2040-robot-assembled-with-75-1-hp-motors
• https://www.pololu.com/product/5012
• https://github.com/pololu/zumo-2040-robot

In my opinion, you should only introduce a named tuple to your code when you&aposre updating a preexisting API that was already returning a tuple or you are wrapping a tuple return value from another API.

Let&aposs start with when you should use named tuples. Usually an API that returns a tuple does so when you only have a couple of items in your tuple and the name of the function returning the tuple id enough to explain what each item in the tuple does. But sometimes your API expands and you find that your tuple is no longer self-documenting purely based on the name of the API (e.g., get_mouse_position() very likely has a two-item tuple of X and Y coordinates of the screen while app_state() could be a tuple of anything). When you find yourself in the situation of needing your return type to describe itself and a tuple isn&apost cutting it anymore, then that&aposs when you reach for a named tuple.

So why not start out that way? In a word: simplicity. Now, some of you might be saying to yourself, "but I use named tuples because they are so simple to define!" And that might be true for when you define your data structure (and I&aposll touch on this "simplicity of definition" angle later), but it actually makes your API more complex for both you and your users to use. For you, it doubles the data access API surface for your return type as you have to now support index-based and attribute-based data access forever (or until you choose to break your users and change your return type so it doesn&apost support both approaches). This leads to writing tests for both ways of accessing your data, not just one of them. And you shouldn&apost skimp on this because you don&apost know if your users will use indexes or attribute names to access the data structure, nor can you guarantee someone won&apost break your code in the future by dropping the named tuple and switching to some custom type (thanks to Python&aposs support of structural typing (aka duck typing), you can&apost assume people are using a type checker and thus the structure of your return type becomes your API contract). And so you need to test both ways of using your return type to exercise that contract you have with your users, which is more work than had you not used a named tuple and instead chose just a tuple or just a class.

Named tuples are also a bit more complex for users. If you&aposre reaching for a named tuple you&aposre essentially signalling upfront that the data structure is too big/complex for a tuple alone to work. And yet by using a named tuple means you are supporting the tuple approach even if you don&apost think it&aposs a good idea from the start. On top of that, the tuple API allows for things that you probably don&apost want people doing with your return type, like slicing, iterating over all the items as if they are homogeneous, etc. Basically my argument is the "flexibility" of having the index-based access to the data on top of the attribute-based access isn&apost flexible in a good way.

So why do people still reach for named tuples when defining return types for new APIs? I think it&aposs because people find them faster to define a new type than writing out a new class. Compare this:

Point = namedtuple(&aposPoint&apos, [&aposx&apos, &aposy&apos, z&apos])

To this:

class Point: def __init__(self, x, y, z): self.x = x self.y = y self.z = z

So there is a clear difference in the amount of typing. But there are three more ways to do the same data structure that might not be so burdensome. One is dataclasses:

@dataclasses.dataclass class Point: x: int y: int z: int

Another is simply a dictionary, although I know some prefer attribute-based access to data so much that they won&apost use this option). Toss in a TypedDict and you also get editor support as well:

class Point(typing.TypedDict): x: int y: int z: int # Alternatively ... Point = typing.TypedDict("Point", {"x": int, "y": int, "z": int})

A third option is types.SimpleNamespace if you really want attributes without defining a class:

Point = lambda x, y, z: types.SimpleNamespace(x=x, y=y, z=z)

If none of these options work for you then you can always hope that somehow I convince enough people that my record/struct idea is a good one and get into the language. 😁

My key point in all of this is to prefer readability and ergonomics over brevity in your code. That means avoiding named tuples except where you are expanding to tweaking an existing API where the named tuple improves over the plain tuple that&aposs already being used.

A hot-fix release 1.0.13-1, consisting of two small PRs relative to the last regular CRAN release 1.0.13, just arrived on CRAN. When we prepared 1.0.13, we included a change related to the ‘tightening’ of the C API of R itself. Sadly, we pinned an expected change to ‘comes with next (minor) release 4.4.2’ rather than now ‘next (normal aka major) release 4.5.0’. And now that R 4.4.2 is out (as of two days ago) we accidentally broke building against the header file with that check. Whoops. Bugs happen, and we are truly sorry—but this is now addressed in 1.0.13-1.

The normal (bi-annual) release cycle will resume with 1.0.14 slated for January. As you can see from the NEWS file of the development branch, we have a number of changes coming. You can safely access that release candidate version, either off the default branch at github or via r-universe artifacts.

The list below details all changes, as usual. The only other change concerns the now-mandatory use of Authors@R.

Changes in Rcpp release version 1.0.13-1 (2024-11-01)

• Changes in Rcpp API:

  • Use read-only VECTOR_PTR and STRING_PTR only with with R 4.5.0 or later (Kevin in #1342 fixing #1341)

• Changes in Rcpp Deployment:

  • Authors@R is now used in DESCRIPTION as mandated by CRAN

Thanks to my CRANberries, you can also look at a diff to the previous release Questions, comments etc should go to the rcpp-devel mailing list off the R-Forge page. Bugs reports are welcome at the GitHub issue tracker as well (where one can also search among open or closed issues).

If you like this or other open-source work I do, you can sponsor me at GitHub.

This post by Dirk Eddelbuettel originated on his Thinking inside the box blog. Please report excessive re-aggregation in third-party for-profit settings.

Something many people don’t realize is that I didn’t write the original coverage.py. It was written by Gareth Rees in 2001. I’ve been extending and maintaining it since 2004. This ancient history came up this week, so I grabbed the 2001 version from archive.org to keep it here for posterity.

I already had a copy of Gareth’s original page about coverage.py, which now links to my local copy of coverage.py from 2001. BTW: that page is itself a historical artifact now, with the header from this site as it looked when I first copied the page.

The original coverage.py was a single file, so the “coverage.py” name was literal: it was the name of the file. It only had about 350 lines of code, including a few to deal with pre-2.0 Python! Some of those lines remain nearly unchanged to this day, but most of it has been heavily refactored and extended.

Coverage.py now has about 20k lines of Python in about 100 files. The project now has twice the amount of C code as the original file had Python. I guess in almost 20 years a lot can happen!

It’s interesting to see this code again, and to reflect on how far it’s come.

We can use uv to make linting and testing on GitHub Actions around 1.5 times as fast.

Linting

When using pre-commit for linting:

name: Lint on: [push, pull_request, workflow_dispatch] env: FORCE_COLOR: 1 permissions: contents: read jobs: lint: runs-on: ubuntu-latest steps: - uses: actions/checkout@v4 with: persist-credentials: false - uses: actions/setup-python@v5 with: python-version: "3.x" cache: pip - uses: pre-commit/action@v3.0.1

We can replace pre-commit/action with tox-dev/action-pre-commit-uv:

- uses: actions/setup-python@v5 with: python-version: "3.x" - cache: pip - - uses: pre-commit/action@v3.0.1 + - uses: tox-dev/action-pre-commit-uv@v1 name: Lint on: [push, pull_request, workflow_dispatch] env: FORCE_COLOR: 1 permissions: contents: read jobs: lint: runs-on: ubuntu-latest steps: - uses: actions/checkout@v4 with: persist-credentials: false - uses: actions/setup-python@v5 with: python-version: "3.x" - uses: tox-dev/action-pre-commit-uv@v1

This means uv will create virtual environments and install packages for pre-commit, which is faster for the initial seed operation when there's no cache.

Lint comparison

For example: python/blurb#32

Before After Times faster No cache 60s 37s 1.62 With cache 11s 11s 1.00 Testing

When testing with tox:

name: Test on: [push, pull_request, workflow_dispatch] permissions: contents: read env: FORCE_COLOR: 1 jobs: test: runs-on: ubuntu-latest strategy: fail-fast: false matrix: python-version: ["3.9", "3.10", "3.11", "3.12", "3.13", "3.14"] steps: - uses: actions/checkout@v4 with: persist-credentials: false - name: Set up Python ${{ matrix.python-version }} uses: actions/setup-python@v5 with: python-version: ${{ matrix.python-version }} allow-prereleases: true cache: pip - name: Install dependencies run: | python --version python -m pip install -U pip python -m pip install -U tox - name: Tox tests run: | tox -e py

We can replace tox with tox-uv:

- name: Set up Python ${{ matrix.python-version }} uses: actions/setup-python@v5 with: python-version: ${{ matrix.python-version }} allow-prereleases: true - cache: pip - - name: Install dependencies - run: | - python --version - python -m pip install -U pip - python -m pip install -U tox + - name: Install uv + uses: hynek/setup-cached-uv@v2 - name: Tox tests run: | - tox -e py + uvx --with tox-uv tox -e py name: Test on: [push, pull_request, workflow_dispatch] permissions: contents: read env: FORCE_COLOR: 1 jobs: test: runs-on: ubuntu-latest strategy: fail-fast: false matrix: python-version: ["3.9", "3.10", "3.11", "3.12", "3.13"] steps: - uses: actions/checkout@v4 with: persist-credentials: false - name: Set up Python ${{ matrix.python-version }} uses: actions/setup-python@v5 with: python-version: ${{ matrix.python-version }} allow-prereleases: true - name: Install uv uses: hynek/setup-cached-uv@v2 - name: Tox tests run: | uvx --with tox-uv tox -e py

tox-uv is tox plugin to replace virtualenv and pip with uv in your tox environments. We only need to install uv, and use uvx to both install tox-uv and run tox, for faster installs of tox, the virtual environment, and the dependencies within it.

Test comparison

For example: python/blurb#32

Before After Times faster No cache 2m 0s 1m 26s 1.40 With cache 1m 58s 1m 22s 1.44 Bonus tip

Run the new tool zizmor to find security issues in GitHub Actions.

Header photo: "Road cycling at the 1952 Helsinki Olympics" by Olympia-Kuva Oy & Helsinki City Museum, Public Domain.

Surprise! This blog post series has now been moved to blogs.kde.org so it’s now open for others to participate and contribute! This week’s post can be found at https://blogs.kde.org/2024/11/02/this-week-in-plasma-spoooooky-ooooooooom-notifications

That’s probably where it should have been all along, as this work is much bigger than me. I’ll remain the editor-in-chief for now, but do welcome contributions to help lighten the load.

Unfortunately, due to GDPR restrictions, I’m unable to migrate existing email subscribers to the new email digest over there. So if you’d like to re-subscribe to “This week in Plasma.” head to https://newsletter.kde.org/subscription/form and re-subscribe.

I’ll still be blogging here about KDE topics of interest to me and hopefully you as well, just not the weekly Plasma news. So I do hope you’ll stick around.

Two months ago I bought a Thinkpad X1 Yoga Gen3 [1]. I’m still very happy with it, the screen is a great improvement over the FullHD screen on my previous Thinkpad. I have yet to discover what’s the best resolution to have on a laptop if price isn’t an issue, but it’s at least 1440p for a 14″ display, that’s 210DPI. The latest Thinkpad X1 Yoga is the 7th gen and has up to 3840*2400 resolution on the internal display for 323DPI. Apple apparently uses the term “Retina Display” to mean something in the range of 250DPI to 300DPI, so my current laptop is below “Retina” while the most expensive new Thinkpads are above it.

I did some tests on external displays and found that this Thinkpad along with a Dell Latitude of the same form factor and about the same age can only handle one 4K display on a Thunderbolt dock and one on HDMI. On Reddit u/Carlioso1234 pointed out this specs page which says it supports a maximum of 3 displays including the built in TFT [2]. The Thunderbolt/USB-C connection has a maximum resolution of 5120*2880 and the HDMI port has a maximum of 4K. The latest Yoga can support four displays total which means 2*5K over Thunderbolt and one 4K over HDMI. It would be nice if someone made a 8000*2880 ultrawide display that looked like 2*5K displays when connected via Thunderbolt. It would also be nice if someone made a 32″ 5K display, currently they all seem to be 27″ and I’ve found that even for 4K resolution 32″ is better than 27″.

With the typical configuration of Linux and the BIOS the Yoga Gen3 will have it’s touch screen stop working after suspend. I have confirmed this for stylus use but as the finger-touch functionality is broken I couldn’t confirm that. On r/thinkpad u/p9k told me how to fix this problem [3]. I had to set the BIOS to Win 10 Sleep aka Hybrid sleep and then put the following in /etc/systemd/system/thinkpad-wakeup-config.service :

# https://www.reddit.com/r/thinkpad/comments/1blpy20/comment/kw7se2l/?context=3 [Unit] Description=Workarounds for sleep wakeup source for Thinkpad X1 Yoga 3 After=sysinit.target After=systemd-modules-load.service [Service] Type=oneshot ExecStart=/bin/sh -c "echo 'enabled' > /sys/devices/platform/i8042/serio0/power/wakeup" ExecStart=/bin/sh -c "echo 'enabled' > /sys/devices/platform/i8042/serio1/power/wakeup" ExecStart=/bin/sh -c "echo 'LID' > /proc/acpi/wakeup" [Install] WantedBy=multi-user.target

Now it works fine, for stylus at least. I still get kernel error messages like the following which don’t seem to cause problems:

wacom 0003:056A:5146.0005: wacom_idleprox_timeout: tool appears to be hung in-prox. forcing it out.

When it wasn’t working I got the above but also kernel error messages like:

wacom 0003:056A:5146.0005: wacom_wac_queue_insert: kfifo has filled, starting to drop events

This change affected the way suspend etc operate. Now when I connect the laptop to power it will leave suspend mode. I’ve configured KDE to suspend when the lid is closed and there’s no monitor connected.

• [1] https://etbe.coker.com.au/2024/01/29/thinkpad-x1-yoga-gen3/
• [2] https://tinyurl.com/2cvq6qts
• [3] https://tinyurl.com/26ho6vxk

Related posts:

1. Thinkpad X1 Yoga Gen3 I just bought myself a Thinkpad X1 Yoga Gen3 for...
2. More About Kogan 5120*2160 Monitor On the 18th of May I blogged about my new...
3. Thinkpad X1 Carbon Gen 6 In February I reviewed a Thinkpad X1 Carbon Gen 1...

I previously wrote about the possibility of transferring work between devices as an alternative to “convergence” (using a phone or tablet as a desktop) [1]. This idea has been implemented in some commercial products already.

MrWhosTheBoss made a good YouTube video reviewing recent Huawei products [2]. At 2:50 in that video he shows how you can link a phone and tablet, control one from the other, drag and drop of running apps and files between phone and tablet, mirror the screen between devices, etc. He describes playing a video on one device and having it appear on the other, I hope that it actually launches a new instance of the player app as the Google Chromecast failed in the market due to remote display being laggy. At 7:30 in that video he starts talking about the features that are available when you have multiple Huawei devices, starting with the ability to move a Bluetooth pairing for earphones to a different device.

At 16:25 he shows what Huawei is doing to get apps going including allowing apk files to be downloaded and creating what they call “Quick Apps” which are instances of a web browser configured to just use one web site and make it look like a discrete app, we need something like this for FOSS phone distributions – does anyone know of a browser that’s good for it?

Another thing that we need is to have an easy way of transferring open web pages between systems. Chrome allows sending pages between systems but it’s proprietary, limited to Chrome only, and also takes an unreasonable amount of time. KDEConnect allows sharing clipboard contents which can be used to send URLs that can then be pasted into a browser, but the process of copy URL, send via KDEConnect, and paste into other device is unreasonably slow. The design of Chrome with a “Send to your devices” menu option from the tab bar is OK. But ideally we need a “Send to device” for all tabs of a window as well, we need it to run from free software and support using your own server not someone else’s server (AKA “the cloud”). Some of the KDEConnect functionality but using a server rather than direct connection over the same Wifi network (or LAN if bridged to Wifi) would be good.

What else do we need?

• [1] https://etbe.coker.com.au/2024/04/26/convergence-vs-transference/
• [2] https://www.youtube.com/watch?v=IhYDtLzmRQI

Related posts:

1. Convergence vs Transference I previously wrote a blog post titled Considering Convergence [1]...
2. Moving from a Laptop to a Cloud Lifestyle My Laptop History In 1998 I bought my first laptop,...
3. Cheap NAS Devices Suck There are some really good Network Attached Storage (NAS) devices...

I recently had someone describe a Mac Mini as a “workstation”, which I strongly disagree with. The Wikipedia page for Workstation [1] says that it’s a type of computer designed for scientific or technical use, for a single user, and would commonly run a multi-user OS.

The Mac Mini runs a multi-user OS and is designed for a single user. The issue is whether it is for “scientific or technical use”. A Mac Mini is a nice little graphical system which could be used for CAD and other engineering work. But I believe that the low capabilities of the system and lack of expansion options make it less of a workstation.

The latest versions of the Mac Mini (to be officially launched next week) have up to 64G of RAM and up to 8T of storage. That is quite decent compute power for a small device. For comparison the HP ML 110 Gen9 workstation I’m currently using was released in 2021 and has 256G of RAM and has 4 * 3.5″ SAS bays so I could easily put a few 4TB NVMe devices and some hard drives larger than 10TB. The HP Z640 workstation I have was released in 2014 and has 128G of RAM and 4*2.5″ SATA drive bays and 2*3.5″ SATA drive bays. Previously I had a Dell PowerEdge T320 which was released in 2012 and had 96G of RAM and 8*3.5″ SAS bays.

In CPU and GPU power the recent Mac Minis will compare well to my latest workstations. But they compare poorly to workstations from as much as 12 years ago for RAM and storage. Which is more important depends on the task, if you have to do calculations on 80G of data with lots of scans through the entire data set then a system with 64G of RAM will perform very poorly and a system with 96G and a CPU less than half as fast will perform better. A Dell PowerEdge T320 from 2012 fully loaded with 192G of RAM will outperform a modern Mac Mini on many tasks due to this and the T420 supported up to 384G.

Another issue is generic expansion options. I expect a workstation to have a number of PCIe slots free for GPUs and other devices. The T320 I used to use had a PCIe power cable for a power hungry GPU and I think all the T320 and T420 models with high power PSUs supported that.

I think that a usable definition of a “workstation” is a system having a feature set that is typical of servers (ECC RAM, lots of storage for RAID, maybe hot-swap storage devices, maybe redundant PSUs, and lots of expansion options) while also being suitable for running on a desktop or under a desk. The Mac Mini is nice for running on a desk but that’s the only workstation criteria it fits. I think that ECC RAM should be a mandatory criteria and any system without it isn’t a workstation. That excludes most Apple hardware. The Mac Mini is more of a thin-client than a workstation.

My main workstation with ECC RAM could run 3 VMs that each have more RAM than the largest Mac Mini that will be sold next week.

If 32G of non-ECC RAM is considered enough for a “workstation” then you could get an Android phone that counts as a workstation – and it will probably cost less than a Mac Mini.

• [1] https://en.wikipedia.org/wiki/Workstation

Related posts:

1. BTRFS Rebuild Time In February I replaced a Dell T320 server with a...
2. SSD for a Workstation SSDs have been dropping in price recently so I just...
3. T320 iDRAC Failure and new HP Z640 The Dell T320 Almost 2 years ago I made a...

Welcome to the new home of "This Week in Plasma"! No longer is it a private personal thing on my (Nate Graham's) blog, but now it's a weekly series hosted here on KDE's infrastructure, open to anyone's participation and contribution! I'll remain the editor-in-chief for now, and welcome contributions via direct push to the relevant merge request on invent.kde.org. And after a post is published, if you find a typo or broken link, feel free to just fix it.

Anyway, this week we added a useful service to detect out-of-memory (OOM) conditions, did some UI polishing, and also a lot of bug-fixing! Check it out:

Notable New Features

When the system has run out of memory (OOM) and the kernel terminated an app, there's now a little service to detect this and show you a system notification explaining what happened, plus suggestions for what you can do about it in the future. (Harald Sitter, 6.3.0. Link)

Notable UI Improvements

The Emoji Selector app now does sub-string matching from the middle of words too, so you can find emojis more easily. (Eren Karakas, 6.2.3. Link)

The grouping indicator in the Task Manager widget (which looks like a little plus sign) is no longer always green; now it follows the current accent color! (Tem PQD, 6.3.0. Link)

Appropriate symbolic icons from will now be automatically substituted for apps' system tray icons — when they exist in the icon theme. If you'd like to extend this to more apps, figure out what icon name the app asks for, then create a symbolic version of it, append -symbolic to the name, and submit it to the Breeze Icons repo! (Marco Martin, 6.3.0. Link)

Notable Bug Fixes

Fixed a way that misbehaving XWayland-using apps could make KWin freeze. (Vlad Zahorodnii, 6.2.3. Link)

Fixed a bug causing notifications about modifier key changes (if you've turned them on) to not actually appear. (Nicolas Fella, 6.2.3. Link)

Fixed a bug in the Bluetooth pairing wizard that caused it to be annoying to enter digits. (Daniil-Viktor Ratkin, 6.2.3. Link)

Reviews on Discover's app pages now load properly when the app is accessed from the Home page, as opposed to after browsing or searching. (Aleix Pol Gonzalez, 6.2.3. Link)

Fixed the Task Manager widget's setting to reverse the direction that new tasks appear in so that it works as originally designed, and not only halfway there. (Michael Rivnak, 6.2.3. Link)

Fixed a bug that caused customized user avatars for other currently-logged-in users to not be displayed in the User Switcher widget. (Blazer Silving, 6.2.3. Link)

Fixed a bug causing the "Show Logout Screen" item in the desktop context menu to not show enough items if you had customized the "default logout option" in the past, back when we offered that as a user-facing setting. (Nate Graham, 6.2.3 Link)

With global animations set to "instant", window thumbnails in KWin's Desktop Grid effect are no longer too small. (Niccolò Venerandi, 6.2.3. Link)

When you've got the Application Dashboard widget set up with an icon naming style that causes the text to be long and get elided, hovering over the icon now shows a tooltip with the correct full text in it. (Tomislav Pap, 6.2.3. Link)

Fixed a case where KWin could crash when moving certain drawing tablet pens to the surface of the pad. (Vlad Zahorodnii, 6.3.0. Link)

Fixed an issue that caused XWayland-using apps to resize in a janky and jumpy manner. (Vlad Zahorodnii, 6.3.0. Link, see detailed blog post)

How You Can Help

KDE has become important in the world, and your time and contributions have helped us get there. As we grow, we need your support to keep KDE sustainable.

You can help KDE by becoming an active community member and getting involved somehow. Each contributor makes a huge difference in KDE — you are not a number or a cog in a machine!

You don’t have to be a programmer, either. Many other opportunities exist:

• Filter and confirm bug reports, maybe even identify their root cause
• Contribute designs for wallpapers, icons, and app interfaces
• Design and maintain websites
• Translate user interface text items into your own language
• Promote KDE in your local community
• …And a ton more things!

You can also help us by donating to our yearly fundraiser! Any monetary contribution — however small — will help us cover operational costs, salaries, travel expenses for contributors, and in general just keep KDE bringing Free Software to the world.

To get a new Plasma feature or a bugfix mentioned here, feel free to push a commit to the relevant merge request on invent.kde.org.

In Plasma 6.2, KWin switched from doing linear blending with HDR to blending in a gamma 2.2 space. Let’s take a look at what that means, and why it was done.

What is blending?

When KWin composites, it paints window by window, going by the order of how the windows are stacked - the bottom-most window first, the topmost window last. When a window is opaque, you just overwrite the pixels in the framebuffer with the ones from the window. When a window is semi-transparent though, we need to additionally do blending.

To do blending, the GPU calculates the value that the framebuffer should have with some equation that gets the pixel from the window and the existing value in the framebuffer, and outputs some appropriate value. Usually that equation is1

framebuffer = framebuffer.rgb * (1 - window.alpha) + window.rgb * window.alpha

where window.alpha is a per-pixel value that describes how opaque the pixel is.

Blending with color management

In Plasma 5, compositing happened in the display color space. As displays could be assumed to be roughly the same, with brightness levels encoded in sRGB, that resulted in blending looking very similar everywhere.

With HDR in Plasma 6 however, that assumption was no longer true, so we had to do something else. As it was considered the most “correct” thing and allows us to ensure the exact same blending result even with displays that have wildly different colorspaces, linear blending was chosen for Plasma 6.0. The result of linear blending would look different from sRGB, but it would at least be consistent everywhere.

With linear blending, instead of just taking the rgb values as is, you first convert them into light-linear values, for example with sRGB you’d just do

rgb_linear = pow(rgb_sRGB, 2.2)

then apply the blending equation, and at the end convert it back to whatever encoding the screen needs.

Because of limitations in KWin’s renderer and the ancient OpenGL versions KWin supports, the only way to do this was to render first into a so-called shadow buffer2 with linear values, and after compositing a second shader pass would run, taking that shadow buffer as the input and outputting a buffer with non-linear values that’s suitable for sending to the screen.

The caveats of linear blending

It’ll be pretty obvious to most that doing a fullscreen copy each frame is not ideal for performance or battery life, but there was even a second problem: If you use only 8 or 10 bits per color (bpc) to store linear brightness values, you get visible banding in the dark areas of the image, as human vision is very non-linear. So on top of doing fullscreen copies, KWin also had to use a floating point buffer with 16 bpc, which uses twice the memory bandwidth vs. 8 bpc and makes performance and power usage even worse.

With that performance hit, we couldn’t enable this on all hardware, but had to restrict linear blending to those displays where HDR or an ICC profile is enabled. This threw the whole consistency benefit out of the window, because now a semi-transparent surface would look a lot more transparent just because you enabled HDR… causing the very problem we wanted to avoid!

SDR HDR

We had to do something when blending in HDR though, so a different approach had to be taken.

Custom transfer functions

When storing colors in buffers, usually we use non-linear encodings with transfer functions like sRGB or PQ. All the transfer functions have some sort of luminance levels attached to them, for example an sRGB value of 1.0 is defined to result in a luminance of 80 nits in its reference viewing environment3.

There’s no reason to be restricted to those definitions though - we can make transfer functions that mean whatever we want or need. In KWin’s case, we switched the shadow buffer from using a linear encoding to a gamma 2.2 encoding, in which 1.0 means the maximum luminance of your monitor. This means we do blending in a very similar way as on SDR screens4, and translucent surfaces on the screen look pretty much the same again, no matter what display settings you have.

As the gamma 2.2 encoding allocates more numbers to darker parts of the image, we can also avoid banding with fewer bits per color. Whenever HDR is enabled and the driver supports buffers with 10 bpc, KWin now prefers to use that instead of 16 bpc, alleviating some of the performance issues. There was still more that could be done though…

KMS offloading

On most graphics cards, the scanout hardware that takes care of sending the image to the display has some fixed function blocks to change the colors in various ways - the most common being a simple look up table (LUT) per color channel.

Through the DRM/KMS API, the compositor can set this LUT, so we can use it to change the encoding from whatever we did blending in to the one the display needs. With HDR screens, this means we

• convert from our shadow buffer encoding with gamma 2.2 and the maximum luminance of the screen to linear
• possibly apply rgb factors for night light
• convert from linear to the PQ encoding the screen needs

With that LUT in place, we don’t have to run a shader pass to convert from the shadow buffer encoding to the screen anymore, so the whole fullscreen copy falls away.

Except for a few additional instructions in the shaders used for compositing, enabling HDR in Plasma 6.2 thus has no performance impact anymore on the vast majority of hardware!

1. in practice, window.rgb is already “pre-multiplied” with window.alpha, but that doesn’t really matter here ↩

2. it’s called that because it’s never actually shown on the screen ↩

3. the viewing environment basically defines a standardized room, in which the content can be viewed as intended without doing any brightness adjustments ↩

4. it’s not exactly the same though. If you need some exactly specific blending behavior in your application, it’s best if you do it yourself ↩

Welcome to the Free Software Supporter, the Free Software Foundation's (FSF) monthly news digest and action update -- being read by you and 231,355 other activists.

Welcome to the Free Software Supporter, the Free Software Foundation's (FSF) monthly news digest and action update -- being read by you and 231,355 other activists.