Alejandro Piad Morffis Profile picture
PhD student. Working on democratizing Machine Learning via @auto_goal. Tweets reflect only my own biases and opinions. También hablo Español. He/Him/Él.
#ReformTheNigeriaPolice 🇳🇬 Profile picture 1 added to My Authors
3 Feb
There seems to be a recent surge in the "HTML is/isn't a programming language" discussion.

While there are a lot of honest misconceptions and also outright bullshit, I still think if we allow for some nuance there is a meaningful discussion to have about it.

My two cents 👇
First, to be bluntly clear, if a person is using this argument to make a judgment of character, to imply that someone is lesser because of their knowledge (or lack of) about HTML or other skills of any nature, then that person is an asshole.

With that out the way...
Why is this discussion meaningful at all?

If you are newcomer to the dev world and you have some misconceptions about it, you can find yourself getting into compromises you're not yet ready for, or letting go options you could take.
Read 10 tweets
2 Feb
This is a Twitter series on #FoundationsOfML. Today, I want to talk about another fundamental question:

❓ What makes a metric useful for Machine Learning?

Let's take a look at some common evaluation metrics and their most important caveats... 👇🧵
Remember our purpose is to find some optimal program P for solving a task T, by maximizing a performance metric M using some experience E.

We've already discussed different modeling paradigms and different types of experiences.

👉 But arguably, the most difficult design decision in any ML process is which evaluation metric(s) to use.
Read 25 tweets
31 Jan
One of the very interesting questions that really got me thinking yesterday (they all did to an important degree) was from @Jeande_d regarding how to balance between learning foundational/transferable skills vs focusing on specific tools.
@Jeande_d My reasoning was that one should try hard not to learn too much of a tool, because any tool will eventually disappear. But tools are crucial to be productive, so one should still learn enough to really take advantage of the unique features of that tool.
@Jeande_d One way I think you can try to hit that sweet spot is practice some sort of dropout regularization on your common tool set.

In every new project, substitute one of your usual tools for some convenient alternative. It will make you a bit less productive, to be sure...
Read 5 tweets
13 Jan
This is a Twitter series on #FoundationsOfML.

❓ Today, I want to start discussing the different types of Machine Learning flavors we can find.

This is a very high-level overview. In later threads, we'll dive deeper into each paradigm... 👇🧵
Last time we talked about how Machine Learning works.

Basically, it's about having some source of experience E for solving a given task T, that allows us to find a program P which is (hopefully) optimal w.r.t. some metric M.

According to the nature of that experience, we can define different formulations, or flavors, of the learning process.

A useful distinction is whether we have an explicit goal or desired output, which gives rise to the definitions of 1️⃣ Supervised and 2️⃣ Unsupervised Learning 👇
Read 18 tweets
12 Jan
A big problem with social and political sciences is that they *look* so intuitive and approachable that literally everyone has an opinion.

If I say "this is how quantum entanglement works" almost no one will dare to reply.

But if I say "this is how content moderation works"...
And the thing is, there is huge amount of actual, solid science on almost any socially relevant topic, and most of us are as uninformed in that as we are on any dark corner of particle physics.

We just believe we can have an opinion, because the topic seems less objective.
So we are paying a huge disrespect to social scientists, who have to deal every day with the false notion that what they have been researching for years is something that anyone, thinking for maybe five minutes, can weigh in. This is of course nonsense.
Read 5 tweets
12 Jan
I'm starting a Twitter series on #FoundationsOfML. Today, I want to answer this simple question.

❓ What is Machine Learning?

This is my preferred way of explaining it... 👇🧵
Machine Learning is a computational approach to problem-solving with four key ingredients:

1️⃣ A task to solve T
2️⃣ A performance metric M
3️⃣ A computer program P
4️⃣ A source of experience E
You have a Machine Learning solution when:

🔑 The performance of program P at task T, as measured by M, improves with access to the experience E.

That's it.

Now let's unpack it with a simple example 👇
Read 23 tweets
7 Jan
Today is #TheoryThursday 🧐!

The most important question in all of Computer Science is probably whether P equals NP. That is, are all problems easy to validate also easy to solve?

How can we even start to ponder this question? 🧵👇
🔖 In case you're just hearing about this, here's a short refresher on what we are talking about:

Let's think now about what would it mean to properly answer this question. 👇
Say we want to answer "yes". How can we do that? Do we have to check that *all* NP problems are actually in P?

👉 To begin, there are infinitely many problems in Computer Science.

There must a better way...
Read 20 tweets
29 Dec 20
I've been a vocal opponent of the "neural networks are brain simulations" analogy, not because it's *wrong* but because I believe it's harmful for beginners.

I want to propose an alternative analogy for approaching deep learning from a dev background.

Think about detecting a face in an image.

How would you even start to write a program for that?

You know it's gonna have something to do with finding a "nose" and two "eyes", but how can you go from an array of pixels to something that looks like an eye, in whatever position?
Now, suppose you have access to thousands of faces and non-faces.

How does that changes the problem?

Instead of thinking in the problem domain (finding faces) you can now take a leap upwards in abstraction, and think in the meta-problem domain (finding face finders).
Read 12 tweets
15 Oct 20
Today is #TheoryThursday 🧐!

I want to talk about what is, possibly, the most important question in all of Computer Science: Does P equal NP?

If you have heard of this and want to learn a bit more, read on... 🧵👇
Computer Science is all about finding clever ways to solve difficult problems.

We have found clever algorithms for a bunch of them: sorting stuff, finding shortest paths, solving equations, simulating physics...

But some problems seem to be way too hard 👇
One example is the Travelling Salesman problem.

❓ Find a cycle starting in your home city to visit all major cities in your country and return home with the least fuel cost.

This is the kind of problem we expect computers to solve easily, right? That's what computers are for!
Read 18 tweets
21 Sep 20
Hey, today is #MindblowingMonday 🤯!

A day to share with you amazing things from every corner of Computer Science.

Today I want to talk about Generative Adversarial Networks 👇
🍬 But let's begin with some eye candy.

Take a look at this mind-blowing 2-minute video and, if you like it, then read on, I'll tell you a couple of things about it...

Generative Adversarial Networks (GAN) have taken by surprise the machine learning world with their uncanny ability to generate hyper-realistic examples of human faces, cars, landscapes, and a lot of other stuff, as you just saw.

Want to know how they work? 👇
Read 12 tweets
17 Sep 20
Hey, guess what, today is #TheoryThursday 🧐!

A silly excuse I just invented to share with you random bits of theory from some dark corner of Computer Science and make it as beginner-friendly as possible 👇
Today I want to talk about *Algorithmic Complexity *.

To get started, take a look at the following code. How long do you think it will take to run it?

Let's make that question more precise. How long do you think it will take to run it in the worst-case scenario?
We can see that the code will run slower if:

👉 your computer is older;
👉 the array is longer; or
👉 x happens to be further to back, or not present at all.

Can we turn these insights into an actual formula? We will have to get rid of ambiguous stuff like "old computers".
Read 21 tweets
11 Sep 20
I made this experiment yesterday:

The thread exploded with hundreds of insights and parallel discussions! Thanks to all who participated.

I'm gonna try to summarize the most interesting takes (from my POV) and thread in my own thoughts. Brace! 👇
First, as some suggested, this does happen in a couple languages:



And even Python has optional semicolons:…
However, these are not so much "errors" fixed by the compiler, but actual features.

They are accounted for in the grammar, and only in specific constructions where it is mostly unambiguous to do so.

(🤔Whether this a good idea or not is a matter for another discussion).
Read 12 tweets