DataTalks.Club

Machine Learning Bookcamp

by Alexey Grigorev

The book of the week from 14 Dec 2020 to 18 Dec 2020

Machine Learning Bookcamp: learn machine learning by doing projects and get the skills needed to work as a data scientist or machine learning engineer.

Questions and Answers

Vladimir Finkelshtein

I’ll take the honor of asking the first question.
Why so many introductory ML books, including yours, choose not to cover timeseries? It is certainly more basic than neural networks and, I imagine, is encountered more often in entry level jobs.

Alexey Grigorev

Oh actually my first outline included a chapter on time series, tight after classification.
There were a couple more chapters that we ended up excluding, e.g. working with text and large scale machine learning. There was concern about the side of the book, so we needed to remove something and ended up removing these things.
The main reason: they are not essential for an ML engineer / data scientist, and rather nice-to-have. Most of the time (in my opinion) we deal with classification problems, and sometimes with regression.
And it’s also possible to pick this topic up after reading the book: the book (hopefully) gives enough foundation to read an article about time series and understand what’s going on.

Wendy Mak

I would like to ask about testing in ml code– from the table of contents it doesn’t seem like your book covers it? (yet I think this is an important but often missed topic… )

Alexey Grigorev

What do you mean by testing? Unit and integration testing or something else?

Wendy Mak

yeah, unit/integration testing

Alexey Grigorev

In my opinion, these topics are not super specific to ML, and there are other good books that cover these topics (maybe somebody could suggest some?)
So that’s why I didn’t include it. I might be wrong - of course my biases and my own experience influenced a lot the table of contents

Alexey Grigorev

I’d be happy to be wrong about it!

Elle O'Brien

i think testing for ML code/models/data is young! i think there will be ML-specific tests eventually as part of the development process, but they’re not yet standardized or widespread. Check out this blog: https://www.jeremyjordan.me/testing-ml/

Elle O'Brien

I have a discussion video with the author of the testing blog, Jeremy Jordan: https://youtu.be/k0naEYedv5I

Neal Lathia

:question: What motivated you to write a book? Alexey Grigorev

Alexey Grigorev

Oh I’m not sure I have a simple answer for that!
It’s not my first book. I previously wrote two books - “Mastering Java for Data Science” and “TensorFlow Projects” (I was a co-author there, with 4 other people)
The first wasn’t really successful - Java is not that popular for ML and I also didn’t invest much time in promoting it
The second was interesting - I really liked the approach of learning different concepts through projects
So when Manning reached out to me saying that they want to write a book with project-based learning (like the TF projects one), I agreed - I wanted to use this approach, but this time using a language more popular than Java :smiley:

Alexey Grigorev

That’s only a part of the story of course, I also like writing, I was blogging for a while - in Russian, this website is abandoned now. But I really like this feeling of sharing knowledge. And writing also helps me personally to learn things really well.
You probably know that as well, that’s why you’re also blogging

Alexey Grigorev

And last but not least, Luca Massaron’s influence was a really important factor when I decided to write a book. I’ve always admired Luca’s work and also wanted to write books like him. So, thanks, Luca!

Neal Lathia

Amazing!

Neal Lathia

I also did my earliest ML work with java :see_no_evil: - back in the days of using the weka library :joy:

George Melvin

Hello! First, let me say that I think that Book of the Week is a fantastic idea :clap::skin-tone-2:
Here’s my question: I’ve recently been thinking a lot about versioning in the ML lifecycle - data versioning, model versioning, feature engineering code,… - and wondered how you solve The Versioning Problem to ensure effective model monitoring, debugging, updating?

Alexey Grigorev

That’s a complex topic, and I’m trying to take a pragmatic approach to versioning.
In my opinion, most of the projects, especially at the beginning, don’t need versioning. I’m mostly talking about data versioning because typically you need to use some tools for that. So it adds an extra layer of complexity for projects. If a project dies, spending time on adding this complexity is wasted.
When it comes to model versioning, it’s a similar situation. I typically do simple versioning e.g. with a timestamp which I include in the response, but there are probably better ways of doing it.

Alexey Grigorev

Elle O’Brien probably you might want to add something :smiley:

Elle O'Brien

Of course I have thoughts on this! As Alexey Grigorev mentions, the need for versioning is proportional to the complexity of your project- meaning, number of people involved, how fast your data/modeling pipeline is changing, and how big the space of models you want to explore is.
When it’s a small project with a static dataset, you can very well get away with Alexey’s approach. More power to you.
DVC (note: i am part of this project and have a vested financial stake in it! so i’m biased) is one of several tools for versioning datasets, code, and models. It basically extends Git versioning and makefiles to datasets and models. Even though we say “data version control” in the name, many people actually use it for models :slightly_smiling_face: If your dataset is static, or is only modified via append-only operations that are easy to filter by timestamp, there is less need for true “data versioning”. Keeping track of the way data is transformed to features and then to a model is where Git versioning + makefiles really shines, in my opinion.
I hope that helps some. Curious what others think!

George Melvin

Alexey Grigorev Thanks for your thoughts around this topic - it is a challenging problem and a tricky one to get right. I certainly agree about waiting until the R&D stage is more mature and there’s a better sense of the viability of a model.

George Melvin

Elle O’Brien Thanks for sharing your thoughts - I agree with what you say on relating the need for versioning to diff velocity in pipeline management. I’ve never quite realised the issue in these terms though so thanks for the insight!
I have used DVC in the past and really like the functionality, especially when working on experiments. I’ve not leveraged it for deployments/rollbacks, however, which is where the biggest challenges (for me) lie. Would be interested to hear from others if they’ve had success.

Elle O'Brien

I have a question: do you think classical hypothesis-testing statistics (using p-values to assess statistical significance, for example) is an important skill for most data scientists? Does it have a role in most modern data science jobs?

Elle O'Brien

I guess I see it as… a lot of ML involves linear regression (or variants on it). If you only care about prediction, you don’t need hypothesis testing. But if you care about understanding what relationships in your data are meaningful, you probably do. How often does this really come up, though?

Alexey Grigorev

Not really often. Typically we need this in experiments
E.g. if we have a new recommender system, we want to test it in online settings - do A/B test or A/B/C test, etc.
The data isn’t necessarily normally distributed, so sometimes we need to do a Mann-Whitney U test instead of the usual T-test. So knowing these kinds of things might be important for that
On the other hand, we have a stats engine for running experiments, so actually this kind of knowledge is not required on a daily basis. We just needed to implement it once and that was enough
So it’s not something we need often, it’s more like a nice-to-have skill. We also don’t typically check these kind of things during the interviews - at least for data scientists.
Data analysts, on the other hand, might actually get a few stats questions during the interviews

Alexey Shvets

Questions:

  1. What do you like the most in your book?
  2. What part of the book would you like to improve/include if you had more time/energy?
Alexey Grigorev

Hey Alexey, thanks for your questions
> What do you like the most in your book?
I like that it’s project-based. For me personally this approach works better than “theory first, application second”. Instead, I first introduce the problem and then show how to solve it
> What part of the book would you like to improve/include if you had more time/energy?
First of all, I need to find the energy to finish it :sweat_smile:
When it comes to improving, there are a lot of small things that could be rephrased, edited, etc, but it takes too much time.
Probably instead I’d rather spend this time writing something new once I finish this one

Alexey Shvets

Alex thanks for your answers! Honestly I love your approach and your book! I will definitely buy a hard copy as soon as it will be released!

Alper Demirel

How do you get the motivation to work with the book? How do you focus?

Alexey Grigorev

My content development editor is doing a great job pinging me every week and asking about the progress. That definitely helps.
But what helps even more is the positive feedback I’m getting about the book. After reading some of the messages on LinkedIn, Twitter or here in this Slack, I feel very motivated to work on it.
With focus it’s more difficult though - my kid makes sure I don’t get any focus time :slightly_smiling_face: so the only time I can really focus is after 10 pm. Also sometimes I wake a bit earlier and work on the book while everyone is asleep

Alper Demirel

Thanks sir for reply, love to your child :star-struck:

Karthy

I have seen many books about machine learning. How is your book different from other books? What value do you bring to the machine learning community with your book?

Alexey Grigorev

First, I have a very specific audience in mind - software engineers who want to get into machine learning. Being a developer myself, I know the kinds of problems devs have when transitioning, so I try to teach ML in a way that will work for them.
I do that by keeping the book very practical. The amount of theory is kept to the minimum, and I cover the stuff that is really required at work. For example, I talk about model deployment quite early in the book. I also spend a lot of time talking about evaluation metrics.
The format is project-based, so we first start with a problem and then find a solution to the problem. This helps to keep the book focused.
Interestingly, this way worked also for other kinds of audiences - I got quite positive feedback from data analysts who want to transition to data science and even from product managers.

Alexey Grigorev

Okay I really like my answer, I’m going to copy it to notion and use it as my elevator pitch when somebody asks me what makes my book stand out :smile:

Karthy

Thanks for your replies. I am looking forward to read your book.

Sejal Vaidya

This book introduces machine learning to engineers like me really well, and gives a good insight on designing workflows.
Do you plan to write any other book after this, that could cover Machine Learning at Scale?
Here, I refer to some of the questions asked above regarding Versioning, Monitoring, Testing, as well as use of more Distributed technologies.

Alexey Grigorev

I don’t think I have enough experience with these kinds of things to write a book about them.
But I do have some ideas of what the next thing may look like.
I want to write about the architectural design of ML services, like how to design and architect a recommender system and things like that.
Some topics I brainstormed about included these:

  • A/B testing
  • Vandalism detection
  • Unsupervised near-duplicate detection
  • Duplicate detection in online marketplaces
  • Serving deep learning models at scale
  • RTB online learning
  • Personalized newsfeed ranking
  • E-commerce search
  • Recommender engine
  • Visual search
  • Fraud detection in marketplaces
  • Matching in two-side marketplaces
  • Dynamic pricing
    I’ll probably narrow it down to 8-10 topics. Then start with a course first and see how it goes. If I like it, I might convert it to a bunch of articles, and if it works out and I don’t lose motivation, I’ll convert them into a book.
    That’s just an idea, let’s see if I actually decide to do it after finishing with ML bookcamp
Sejal Vaidya

Thank you for answering and sharing your plan! That’s an interesting list of use-cases. Would love to see more architectural content on those topics.

Ashutosh Sanzgiri

Hi Alexey, I am curious as to how you selected the datasets to illustrate the various ML techniques in your book. It is always a challenge to pick datasets that are more than “toy”, and somewhat “real world”. I see that a few datasets from Kaggle (did you select contests in which you can continue to make submissions?). Do you provide next steps for readers to continue with their learning. Sorry, I have only skimmed the book and seen the sections that Manning decodes for you.

Alexey Grigorev

When selecting datasets I was thinking about these things:

  • how practical is the problem? How close is it to real world?
  • how often this dataset is used in other books and tutorials?
    I wanted to use something practical, but not something super common
    So I didn’t want to use iris, titanic, mnist or Boston housing. Also I decided not to include the flights delay dataset, but was pretty close to doing it
Alexey Grigorev

As for the next steps, at the end of each chapter, I suggest to

  • try the same thing with some other datasets
  • explore a few extra things on your own
    I recommend to do these exercises to take most out of the book
Alexey Grigorev

The data is not from competitors, but from kaggle datasets, so it’s not possible to submit the solution to kaggle

Ashutosh Sanzgiri

Thanks for your replies, Alexey!

Octavian Mocanu

Hi Alexey, my question is what kind of deployments do you present, e.g. using SageMaker, KubeFlow… Maybe also some comparatives? Thx :slightly_smiling_face:

Alexey Grigorev

I was thinking about SageMaker, but there’s already too much AWS in my book :smiley:
So I have these options:

  • in chapter 5, there’s a simple flask+docker webapp deployed with aws elastic beanstalk
  • in chapter 8, which I’m writing right now, I show how to do it with AWS Lambda and Kubeflow
    Oh and it was so nice of AWS to release an update when I was writing chapter 8, so now I need to adjust it to use Docker :sweat_smile:
    Yes, I’ll include a short comparison, when to use which option
Vladimir Finkelshtein

Since you mentioned that projects are the focus of your book, have you considered a chapter on how the project is born? How does one arrive to formulating the questions asked in the project? Maybe some examples of bad questions that could be asked about dataset. How does one choose the ML metrics and relate them to the business goals? How is the project planned? I noticed that all ML books tend to focus on the technical side, and later the data scientist are always criticized for their lack of soft skills.

Alexey Grigorev

I do a bit of that in the first chapter - I describe CRISP-DM. I’m not sure if I should do extensive coverage of it and have a separate chapter… I probably won’t. It’s too late to change the outline anyways.
But I do want to have a separate chapter on data collection - that will be the last chapter of the book (chapter 9)

Alexey Grigorev

I took a note of what you asked, it’s definitely a good topic - perhaps we can cover these topic in more details in some of our events, or a blog post

Alexey Grigorev

Thank you!

dreyy

For someone new to machine learning and have followed some tutorials. I noticed most of the time is spent of processing the data and how the algorithms work isn’t really explained. Do you consider this when writing the book?

Alexey Grigorev

Yes! The datasets that I use are somewhat prepared already, but I also include some data preprocessing steps as well. The focus is on developing the intuition behind the ML algorithms, but it’s not possible to completely avoid data preparation

Alexey Grigorev

Btw, you can also check the code of the book to see how much data prep is there - https://github.com/alexeygrigorev/mlbookcamp-code

Octavian Mocanu

Maybe it was already mentioned, but I think another aspect that is not always considered in ML books is A/B testing ML models, which in production setups is really important. (Here, too, SM offers this possibility :slightly_smiling_face: , but, for sure, it’s not the only framework). WDYT?

Alexey Grigorev

I think you’re right! Could be a nice chapter to add, and indeed not so many books cover it (my previous one about Java does cover it btw :smile:)
I somehow had to make this decision and not include it because it felt to me that it’s not a crucial skill for ML engineers / data scientists. And aslo often it’s not even tested during the interviews (probably because the interviewers also have no clue about it)

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