Immersive Linear Algebra – A free interactive online book • Hacker News Board

Re: Immersive Linear Algebra – A free interactive online book

#61

Post by devin » Tue, Sep 08, 2015, 3:09 PM UTC

EvanKelly wrote: post #54

wingerlang wrote: post #52

Earlier quoted context omitted.

What exactly do you do when you need math skills in developing? What do you develop with it? Some specific examples? I've done math while developing 3D stuff, physics simulation and a lot of things - yet I never felt like my math skill mattered that much. And I really dislike theoretical math like in school.

Math is certainly not for everyone, but I actually found that once I started diving into pure math (NOT what was taught in my school's math curriculum) it was a whole new world. Did your school actually teach pure math? I bet a lot of programmer types had similar frustrations to the computationally intensive version of math taught in many high schools when they knew that these processes could simply be automated.

This. I had the same experience. By the time I realized this, I was sufficiently jaded that it made devoting my own time to learning it sting more than a little.

Re: Immersive Linear Algebra – A free interactive online book

#62

Post by wingerlang » Tue, Sep 08, 2015, 3:10 PM UTC

EvanKelly wrote: post #54

wingerlang wrote: post #52

Earlier quoted context omitted.

What exactly do you do when you need math skills in developing? What do you develop with it? Some specific examples? I've done math while developing 3D stuff, physics simulation and a lot of things - yet I never felt like my math skill mattered that much. And I really dislike theoretical math like in school.

Math is certainly not for everyone, but I actually found that once I started diving into pure math (NOT what was taught in my school's math curriculum) it was a whole new world. Did your school actually teach pure math? I bet a lot of programmer types had similar frustrations to the computationally intensive version of math taught in many high schools when they knew that these processes could simply be automated.

I don't even know what pure math is to be honest. The courses I specifically lost interest in was linear algebra, discrete mathematic and statistic-something. I did however use linear algebra just after while writing a simple collision/physics engine prototype and found that to be very fun.

Re: Immersive Linear Algebra – A free interactive online book

#63

Post by immersivemath » Tue, Sep 08, 2015, 3:14 PM UTC

jimhefferon wrote: post #42

Not Free? That's fine, but I couldn't see a statement of that. If so, I wonder how they plan to do DRM.

This service is free of charge!

Re: Immersive Linear Algebra – A free interactive online book

#64

Post by steamer25 » Tue, Sep 08, 2015, 3:37 PM UTC

geomark wrote: post #46

dalke wrote: post #31

Earlier quoted context omitted.

I see that chapter 10, on eigenvalues/eigenvectors, is "Coming soon!". Eigenvectors never made intuitive sense to me. As with the various decompositions (Cholesky, LU, etc), I could apply the math as algorithms to follow, but never got to the point where felt I could apply them to new problems. Then again, in practice, I've only needed eigenvectors once since college, and it was more a rote implementation described i…

I enjoyed this articled called "Principal Components Analysis for Dummies" that illustrates eigenvectors and eigenvalues. https://georgemdallas.wordpress.com/2013/10/30/principal-com...

There's also this interactive page for eigen- vectors and values: http://setosa.io/ev/eigenvectors-and-eigenvalues/ (as well as a sibling for PCA: http://setosa.io/ev/principal-component-analysis/)

Re: Immersive Linear Algebra – A free interactive online book

#65

Post by cabinpark » Tue, Sep 08, 2015, 3:57 PM UTC

dalke wrote: post #36

cabinpark wrote: post #32

Earlier quoted context omitted.

Interesting. I used linear algebra with quantum mechanics where eigenvectors represent quantum state of the Hamiltonian which is how I initially understood them. And as for TAing, have you ever TA'd? You definitely get a feeling but I can count numerous times when I've stood in front of the tutorial class and asked if there are any questions only to get no response back. I think it's a symptom of first years. I've TA…

I have TA'ed. Asking for questions in public doesn't help much. Students rarely like to admit they don't know something. I was thinking more of when you look at their assignments. There are often multiple ways to approach a problem, and the route chosen can reveal something about one's level of comfort. It doesn't help that university TAs get almost no training in how to be a TA. At least, I didn't.

Yeah I know. It's hard to squeeze information out of them. I actively tell them to please, please come to me if they don't understand something and I have office hours for a reason. Yet no one takes advantage. At a certain point, you can only do so much since I'm a grad student and not a lecturer and my time is finite.

The problem I've found with assignments though is that people copy and cheat. Many times someone will do very well on assignments and then do absolutely terrible on midterms and finals. It's very frustrating. I remember one course where everyone did nearly perfect on the assignments and yet the final and midterm followed the standard bell curve.

Re: Immersive Linear Algebra – A free interactive online book

#66

Post by adam12 » Tue, Sep 08, 2015, 4:22 PM UTC

This is the first time I've ever heard someone say algebra with a hard g sound.

https://www.youtube.com/watch?v=TIcSnsmitHw

Re: Immersive Linear Algebra – A free interactive online book

#67

Post by mrcactu5 » Tue, Sep 08, 2015, 4:34 PM UTC

Are there any ways to contribute?

Re: Immersive Linear Algebra – A free interactive online book

#68

Post by Ocerge » Tue, Sep 08, 2015, 5:06 PM UTC

dagw wrote: post #50

cabinpark wrote: post #24

I always see linear algebra on HN and many people comment on how they never understood the subject. This makes me ask: what exactly is it that people don't get about linear algebra? What makes it appear to be a difficult subject? As someone who has used linear algebra almost every day in some form over the last decade, it's hard to get a perspective of what aspects are challenging to the beginner. And since I TA cour…

The other aspect that I found with LA compared to almost any other math subject I took was that it was almost entirely mechanical with little to no connection between my understanding of the subject and my grade. The exam questions where mostly along the lines of "find the eigenvector" and "find the determinant" rather than "what's an eigenvector" and "what's a determinant", so I got good grades despite not having an…

This, exactly. I could find an orthonormal basis or an eigenvector, but I never quite wrapped my head around their importance, especially visually.

Re: Immersive Linear Algebra – A free interactive online book

#69

Post by memming » Tue, Sep 08, 2015, 5:14 PM UTC

something123 wrote: post #55

In terms of programming and linear algebra - please consult someone who is actually knowledgeable about the subject if you're implementing it in code. Linear algebra without error analysis is very dangerous. Many many things are theoretically useful, but can't be used in practice. You can't calculate determinants, you can't count unique eigen values, you can't use certain decompositions. Unfortunately this isn't real…

and also don't compute the inverse if you don't have to!

Re: Immersive Linear Algebra – A free interactive online book

#70

Post by orange_county » Tue, Sep 08, 2015, 5:18 PM UTC

Thanks for this! I am currently taking linear algebra with Serge Lang's book and I feel that this is a good addition to my studies. When do you expect to have the other chapters done?