Suppose I am trying to iteratively produce a completed image from some subset using a combination of convolutional/DNN methods. What Image norm is best?

The natural (for me) norm to ascribe to an image is to take the bitmap as a vector with L₂. If the input image is anime or something else, the uniform coloring makes this very likely to be a good fit in a low dimension - that is: no overfitting.

However: pictures of fur. Given a small square, the AI, set to extrapolate more fur from that single image, should be expected to get that stuff right next to the given subimage right, but further away, i want it to get the texture right, not the exact representation. So, if the AI shifts the fur far away from the image left by just the right amount, it could get an incredibly poor score.

If I were to use the naive L₂ norm directly, I would be guaranteed to overfit, and you can see this with some of the demo algorithms for image generation around the web. Now, the answer to this is probably to use a fourier or a wavelet transform and then take the L_N norm over the transformed space instead (correct me if I'm wrong.)

However, we get to the most complex class: images with different textures in them. In this case, I have a problem. Wavelet-type transforms don't behave well with discrete boundaries, while pixel-by-pixel methods don't do well with the textured parts of images. Is there a good method of determining image similarity for these cases?

More philosophically, what is the mathematical notion of similarity that our eye picks out? Any pointers or suggestions are appreciated. This is the last of two issues I have with a design I built for a Sparse NN.

Edit: For those interested, here is an example, notice how the predictions tend to blur details

I'm interested in working on an open source project from scratch with a group of like minded people and curious how to get something like that started. Does anyone know of any websites that facilitate that kind of thing? Like where people might propose an project and others can tentatively join?

Last Thursday, at my workplace, we rolled out a software upgrade across the company. The server side was upgraded overnight to ensure there was minimal downtime, and we had instructions for users posted on our Intranet (pinned to the top for the next 4 days), on exactly what they needed to do to run the upgrade on their PCs and ensure everything was working correctly.

The instructions were written with the help of my 4-year-old to ensure it was clear enough for anyone to read and follow along.

I still received at least 40 messages and emails from people complaining the upgrade didn't work or that certain Outlook plugins are now missing (which was covered in the instructions).

My question is, has anyone found a good way to ensure people follow instructions, or the best way to ensure that your instructions are easy to understand and follow along with?

It is very frustrating to take the time to ensure things go smoothly and write what even my 4-year-old thought was clear instruction, and still have a third of the company not be able to figure it out?

This is not meant to be mean hearted in any way, I genuinely would like some advice or tips on how I can improve on this the next time around.

Thanks.

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Does anyone know about flashing a Google mini or amazon alexa or similar device with some other firmware to make it run funky custom stuff and not phone home or is that kinda just impossible?

I tried searching for this on the general Internet but there was too much clutter from the manufacturers to find anything.

This is a recurring post to discuss programming or other technical projects that we've been working on. Tell us about one of your recent projects, either at work or personal projects. What's interesting about it? Are you having trouble with anything?

Specifically, I've got a big honkin' pile of photos stored on an online storage space, and I want some kind of software that lets me share links to a pic, or a group of pics, or a folder, etc ...

... and here's the crux ... without making extra copies of the pics ... just has renamed, custom-permissioned links to the original pic(s).

In database terms, I want something that gives me Views of my photo collection.

I run my own Nextcloud instance, which is close. It has very nice, very granular photo management and sharing capabilities ... but as far as I can tell, whenever I share a pic with someone, it actually makes another copy of it for the shared instance. If I share the photo 5 times w/5 different people/groups, then suddenly, I have 6 copies of the pic.

Any recommendations?

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I'm thinking of registering a new domain to host a personal blog and a few other pages that is somewhat separate from my current personal portfolio page, as the blog will likely not be directly relevant to my work. But since this is a more personal project, I want to branch out in terms of TLDs - I've previously used exclusively .com endings as they lead to the least confusion and are the most accepted.

I'm a little overwhelmed by the number of options these days, so I wanted to take a little straw poll to see which ones people think are the best. The name itself will be my initials "gpxl", and the endings I am considering are

• .info
• .xyz
• .fyi
• .computer
• .me

But I'm curious to see what others think. I would go with .xyz but I feel like then my domain name becomes an unintelligble string of letters - gpxl.xyz, so I'm wondering what others think and what arguments exist for choosing one over another.

P.S. If anyone has recommendations for registars I'm open to those too. Currently using google domains but open to switching.

This is a recurring post to discuss programming or other technical projects that we've been working on. Tell us about one of your recent projects, either at work or personal projects. What's interesting about it? Are you having trouble with anything?

Overview

If you've spent any significant amount of time programming, then you've probably heard discussions about imperative, functional, and declarative programming. These discussions are often mired in technical knowledge and require a fair amount of intuition when trying to grasp the differences between the examples placed in front of us. These different programming styles, usually called programming "paradigms", are discussed as if they exist within a vacuum with complete and total isolation from one another. This only furthers the confusion and frustration among newer programmers especially, which runs counter to the goal of instructing them.

In this post I'll be taking a look at the oft-neglected intersections where these paradigms meet with the hope that the differences between them will be better understood by reframing our existing knowledge of programming basics.

Note: I'll be using PHP for my code examples and will try to provide comments when necessary to point out language quirks.

Understanding Fundamentals is Imperative

Let's start by first reviewing the most basic, fundamental programming paradigm: imperative programming. The term is a bit strange, but the important thing to understand about it is that imperative programming refers to writing software as a series of instructions where you tell the computer how to solve a specific task. For example, if we need to add together a bunch of numbers inside of an array, we might write code that looks like this:

$numbers = [ 8, 31, 5, 4, 20, 78, 52, 18, 96, 27 ];
$sum = 0;
foreach($numbers as $number) {
    $sum += $number;
}

This is a pretty typical example that you've probably encountered in some form or another at some point in your programming studies or career--iterate over an array one element at a time from the first element to the last and add the current element to some accumulating variable that starts at 0. The kind of loop you use may differ, but the general format of the solution looks the same. This is very similar to the way the computer itself performs the task, so the code here is just a relatively human-friendly version of the actual steps the computer performs. This is the essence of imperative programming, the basic building blocks of everything you learn early on.

Abstract Concepts

As the software we write gets larger and more complex, we then tend to rely on "abstractions" to simplify our code and make it easier to understand, reuse, and maintain. For example, if we've written a program that adds arrays of numbers together, then we probably aren't doing that in only one place. Maybe we've written a tool that generates reports on large data sets, such as calculating the total number of sales for a particular quarter, gross profit, net profit, remaining inventory, and any number of other important business-related metrics. Summing numbers could be so common that you use it in 30 different places, so to avoid having to maintain 30 separate instances of our number adding code from above, we define a function:

function sum($numbers) {
    $sum = 0;
    foreach($numbers as $number) {
        $sum += $number;
    }

    return $sum;
}

We do this so frequently in our code that it becomes second nature. We attach so many names and terms to it, too: DRY, abstraction layers, code reuse, separation of concerns, etc. But one thing experienced programmers learn is to write their functions and object and interface methods in such a way that anyone who uses them doesn't need to care about the underlying implementation details, and instead only need to worry about the method name, expected arguments (if any), expected return type (if any), and expected behavior. In other words, they don't need to understand how the function or method completes the intended action, they only need to declare what action they want performed.

A Declaration of Understanding

Anyone who has looked into the concept of the declarative programming paradigm should find those last words familiar: "they don't need to understand how the function or method completes the intended action, they only need to declare what action they want performed". This is the oft-touted explanation of what declarative programming is, the difference between detailing "how" and declaring "what", and I believe that it's this great similarity that causes imperative and declarative programming to become heavily entwined in a programmer's mind and makes it difficult to understand. Take this common example that authors tend to use to try to detail the difference between declarative and imperative programming:

// imperative
function sum($numbers) {
    $sum = 0;
    foreach($numbers as $number) {
        $sum += 0;
    }

    return $sum;
}

// declarative
function sum($numbers) {
    return array_reduce($numbers, fn($x, $y) => $x + $y, 0);
}

The authors will go on to state that in the imperative example, you tell the computer how to sum the numbers, whereas in the declarative example you don't tell the computer how to do it since you don't know anything about the reduce implementation, but intuitively it still feels as if you're telling the computer how to perform its task--you're still defining a function and deciding what its underlying implementation details are, i.e. the steps it needs to take to perform the task, even if its details are abstracted away behind function or method calls that could have varying implementation details of their own. So how the hell is this any different from defining functions like we do in imperative programming?

The answer is simple: it isn't. We've used so many names and terms to describe functions and methods in our ordinary imperative programming, but the truth is that a well-defined function or method serves as a declarative interface to an imperative implementation. Put differently, declarative programming is defining and utilizing simple interfaces that describe what you want accomplished while the underlying implementation details are inevitably written using imperative code.

Functional Differences

Now we can finally tackle one of the biggest trends in programming right now: the functional programming paradigm. But to understand this paradigm, it's important to understand what a "function" is... from a mathematical perspective.

Yes, I know, math tends to be a enthusiasm sink for many, but don't worry, we're not actually going to be doing math. We only need to understand how math treats functions. Specifically, math functions usually look something like f(x) = {insert expression here}, which is loosely equivalent to the following code:

function f($x) {
    return {insert expression here};
}

The important thing to note about functions in math is that you can run them a theoretically infinite number of times on the same input x and still get the same return result. Unlike in a lot of the programs we can write, math functions don't produce side effects. Files aren't written to or destroyed, database entries aren't deleted, some global counter somewhere isn't incremented, and your x doesn't suddenly change. The idea behind functional programming is to embody some of that nature of mathematical functions because they're predictable and always reproducible, and therefore simple to test as well. For example, take the following:

// not functional
function increment(&$x) { // pass by reference--$x will be modified outside of this function!
    $x++;
}

$x = 1;
increment($x);
increment($x);
increment($x);

// functional
function increment($x) { // pass by value--$x will NOT be modified outside of this function!
    return $x + 1;
}

$x = 1;
$y = increment($x);
$y = increment($x);
$y = increment($x);

Note that the first example will change the value of $x on each call, meaning each subsequent call of increment($x) produces a different result. Meanwhile the second example doesn't change $x and so the return value of increment($x) is always the same. This may seem like a silly example, but in larger, more complex software this can be significant. So now that we have an understanding of functions from a mathematical perspective, we have everything we need to actually understand what functional programming is.

Functional programming is a subset of declarative programming. Just like in declarative programming, you use simple interfaces to tell the program what you want to do rather than how to do it. But unlike declarative programming as a whole, functional programming imposes some additional restrictions on what you should and shouldn't do:

• You should encapsulate behavior in pure functions, which always give a consistent output for a given input and don't have side effects.

• You should write functions in such a way that you can compose them together, allowing you to combine and chain behavior to produce new functions or use the output of one as the input for another.

• You should avoid side effects as much as possible.

• You should avoid mutable state (e.g. changing the values in a variable).

• You should avoid sharing state between components.

These restrictions would require an entirely separate post on their own to properly cover and have been covered so many times in so many ways by others elsewhere that it would be superfluous for me to try to add anything more. It's important to note, however, that these restrictions are imposed because they provide some key benefits. By avoiding side effects and by avoiding mutable and shared states, the code you write becomes more predictable and tracing the behavior of an algorithm becomes far simpler. By writing pure, composable functions, you create reusable building blocks that can be strung together in virtually any configuration with predictable results. This makes writing, reading, maintaining, and debugging code easier and less error-prone.

That said, I feel that it's important to note that in the real world when writing practical software that users can interact with, it's simply not possible to completely avoid side effects or mutable state. The very act of creating and updating database entries is itself an act of mutating state, which runs contrary to functional programming principles and is essential for many important software projects. But even if you can't adhere strictly to functional programming principles, it's possible to benefit significantly from being aware of them and integrating them into your own software development strategies.

Let's consider a more practical example to illustrate this. Imagine that you've built a social media website and you're trying to test a push notification system that will be triggered when your user receives a new message. Now imagine your code and unit tests look something like this:

function sendNotification(&$message) { // pass by reference--$message will be modified outside of this function!
    $notification_system = new NotificationSystem();
    if(!$message['sent_push_notification']) {
        $notification_system->sendPushNotification($message);
        $message['sent_push_notification'] = true;
    }
}

function testSendNotification() {
    $message = [
        'user_id'=>'{some_id}',
        'contents'=>'Hi!',
        'sent_push_notification'=>false
    ];

    sendNotification($message);
    sendNotification($message);
}

At a quick glance you probably wouldn't be aware of why the second message didn't send, but the fact that our sendNotification() function mutates the state of the data provided to it is the culprit. This is code that doesn't adhere to functional programming principles since the data provided to it is mutated. As a result, running the function multiple times on the same variable doesn't result in the same behavior as the first call. If we wanted to work around this without adhering to functional programming principles then we would need to manually set $message['sent_push_notification'] = false; between function calls, which makes our unit tests potentially more error-prone. Alternatively we can make a simple change to adhere better to those functional principles:

function sendNotification($message) { // pass by value--$message will NOT be modified outside of this function!
    $notification_system = new NotificationSystem();
    if(!$message['sent_push_notification']) {
        $notification_system->sendPushNotification($message);
        $message['sent_push_notification'] = true;
    }

    return $message;
}

function testSendNotification() {
    $message = [
        'user_id'=>'{some_id}',
        'contents'=>'Hi!',
        'sent_push_notification'=>false
    ];

    sendNotification($message);
    sendNotification($message);
}

Now both notifications will be sent out, which is what we would intuitively expect. You should also notice that the above is also a blend of imperative, declarative, and functional programming. Our function definitions have imperative code, our sendNotification() function adheres to the functional programming principle of avoiding mutable state (well, mostly), and our NotificationSystem object provides a declarative interface for sending a push notification for a message.

Final Thoughts

By viewing these three paradigms not as completely separate concepts but as layers on top of one another, where functional programming is a type of declarative programming which is implemented using imperative programming, we can stop being confused by their similarities and instead find clarification in them. By understanding that imperative programming is the backbone of everything, that declarative programming is just simplifying that backbone with simple interfaces, and that functional programming is simply adding some additional guidelines and restrictions to the way you write code to make it more consistent, reusable, and predictable, we can start to see that we're not choosing one programming paradigm over another, but instead choosing how much consideration we place on the design of the programs we write. Except in purely functional languages, functional programming isn't some alien concept distinct from imperative or declarative programming, but is instead a natural evolution of the two.

There are a lot of details I've glossed over here. Each of these programming paradigms is far too detailed to include a proper analysis in an already lengthy post that tries to separate them from each other and clarify their differences. Blog articles exist in a thousand different places that can do each one far more justice than I can, and programming languages exist that completely cut imperative programming out of the picture. But for your average programmer slinging JavaScript, C, Rust, PHP, or what have you, I hope that this serves as a crucial starting pointing to understanding just what in the hell these functional programming enthusiasts are on about.

I've come across this website recently, and I'm genuinely wondering if it's really that useful for passing interviews.

For example, I think it can not replace a solid background in algorithms/data structures and maybe CS courses in general.

General Programming Q&A thread! Ask any questions about programming, answer the questions of other users, or post suggestions for future threads.

Don't forget to format your code using the triple backticks or tildes:

Here is my schema:

```sql
CREATE TABLE article_to_warehouse (
  article_id   INTEGER
, warehouse_id INTEGER
)
;
```

How do I add a `UNIQUE` constraint?

I could have post this on Reddit but in my experience, nothing really happens over there since things are too impersonal.

I realize that's not an enticing proposition for most people since programmers are usually busy people, but I figure I'd give it a shot. I believe many people that already interacted with me have some idea about my personality. Besides being a stickler for logic, I'm very flexible and eager to learn and make it a habit to force myself to admit when I am wrong. I had to abandon software engineering college because of financial concerns and this hurt me quite a bit, not just because of the content, but because of the social stimulus from my peers.

I already have some knowledge mostly in Python and basic C algorithms, from the basics until rudiments OOP. Math is not my strong suit, but I don't hate it either and I am very fond of logic (including philosophy). I'm also very good at Googling and reading documentation, so I wouldn't give you too much trouble.

I'm proficient in Linux/Unix (as an advanced user, not an administrator). I'm comfortable in the command line and an enthusiastic user of Emacs (but I can use whatever you want of course).

It doesn't even have to be Python, just anything you're comfortable teaching at a beginner level that works on a Mac (and later n a Linux Machine). And is also wouldn't have to be super intensive or frequent, being unemployed (hahaha) I can work around any schedule. I just need some human contact with a nice dude or dudette that cares about imparting knowledge.

My English is pretty good in writing and understanding but I do have a thick accent -- I believe it's understandable though.

I'm super shy and video is not a requirement, but it might be nice.

I'm also a slow learner and have ADHD, so you might need a little patience.

Anyway, here I am asking for help!

EDIT: dear Tilderinos, you're awesome and I love you all. I'm also aware of many if not most learning resources for self-didact beginners programmers on the internet -- especially if they use Python. The reason I'm posting this is that I am failing at learning by myself. I welcome ALL suggestions with great gratitude, but this is not the purpose of this thread.

EDIT2 VERY IMPORTANT!!! I’d be willing to teach Portuguese or anything else I happen to know in exchanging for the tutoring!!!!!!!

EDIT3:

Thank you very much everyone. I'm very sorry tor taking so long to answer. I had to make a decision about my study plans for 2020.

Thing is, back in 2019 I was doing pretty well on a software engineering course at a local private university. But money got tight and I had to drop out. Since then I've been trying to make it on my own, but after more than a year I came to the conclusion that this is simply not going to work. At the university, I was at the top of the class. By myself, I'm a lazy bastard with half the IQ. Go figure.

So I decided that instead of trying force my way into learning by myself, I'll just study for the Brazilian national exam and get into some great public educational facility that will most certainly provide me a better education for free.

I took the exam before without studying, and my grade made the cut. So I'm confident that if apply myself this time I'll be able to enter at least one of three major public universities in my city that offer dozens of IT-related courses.

So I'm laying off from programming until at least January 17 and devoting myself entirely to the exam.

Cheers!

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