Trajectories

[James Edward Gray II]

Looks like there's no gem for this.
Yet.

http://moonbase.rydia.net/software/lazy.rb/

James Edward Gray II

 

[Marnen Laibow-Koser]

Wow, that's very interesting -- thanks for the reference.

Looks like there's no gem for this.
Yet.

But there will be in the future. Perhaps we can require it now, and
block evaluation until the future is resolved.


Best,

 

[Aldric Giacomoni]

http://moonbase.rydia.net/software/lazy.rb/

James Edward Gray II

Well, that'll teach me. How did you find it, out of sheer curiosity? I
did not use lazy as a keyword, so maybe that was it..

 

[Gregory Brown]

When I was a young lad, it used to be that young programmers took a
semester long course on numerical analysis, which started with, and
continuously came back to dealing with the properties of floating
point numbers.

I guess that doesn't happen much anymore.

I took numerical analysis, but ironically, only after dropping my CS
major and going for a math major.
Also, I'll content that abstract algebra was about the best course
I've taken for helping the way I think about programming.

Too bad the CS students are all too busy trying to get their Java/C++
projects to compile

 

[James Edward Gray II]

=20
Well, that'll teach me. How did you find it, out of sheer curiosity? I=20=

did not use lazy as a keyword, so maybe that was it..

I've just been reading this list forever and knew it existed. I had an =
unfair advantage.

Lazy evaluation was a popular topic in Ruby circles sometime back. That =
was when Lazy.rb was invented. I looked into it quite a bit while =
writing this old blog post:

http://blog.grayproductions.net/articles/infinite_streams

James Edward Gray II

 

[Todd Benson]

This isn't an issue of chaotic behaviour (that has a very fixed meaning
mathematically) but of unnoticeable error.

I'm talking about result. A small difference in initial conditions
causes big problem.

The difference between 1e10-13
and 2e10-13 matters a lot when working on a system which needs to be
accurate to a resolution of 1e10-14 but not when working to a resolution = of
1e10-4. The additional nine decimal places tell us nothing meaningful in
this latter case as we'll still end up rounding the result to zero.

Right, sort of. See below.

That's not a bug but a fundamental outcome of the nature of binary coded
non-integral numbers. Many rational non-integral numbers cannot be expres= sed
accurately in binary representations, whilst binary coded decimal brings = a
whole host of other problems: lower information density, higher memory
usage, and heavier processing load. BCD also does nothing to resolve the
problem of how to represent irrational numbers such as =F0.

Ok, not a bug. Just makes you want to scream at somebody (yes the
game thing happened to me recently). The binary inaccuracy thing has
been beaten to death on this list, but you're right.

The imprecision can indeed stack for complex ballistics systems, dependin= g
on the complexity of the forces involved. However to the extent of the
precision chosen for performing these calculations the resultant inaccura= cy
is irrelevant.

I agree. I thought we were talking about a simple game. In any case,
small perversions in data (i.e. rounding beforehand) can cause certain
systems to go haywire. If you stay, for example, at 1e10-4 from the
beginning, you could end up with errors several orders of magnitude
higher, so the "just rounding to zero anyway" argument doesn't make
sense. This probably doesn't apply so much in a simple parabolic
equation, but the equation is still nonlinear, so one must be terribly
wary. Error analysis class was way too long ago, otherwise I'd give
an example. If somebody wants to step in, please do.

http://en.wikipedia.org/wiki/Accuracy_and_precision explains all of this = in
reasonable detail.

Ah, yes, the first thing you learn when studying engineering. I'm
guessing the only thing affected in the result would be accuracy.
Just a guess.

Todd

 

[Eleanor McHugh]

=20
=20
I took numerical analysis, but ironically, only after dropping my CS
major and going for a math major.
Also, I'll content that abstract algebra was about the best course
I've taken for helping the way I think about programming.
=20
Too bad the CS students are all too busy trying to get their Java/C++
projects to compile

Never hire a computer scientist if you can get a maths, physics or =
philosophy grad instead

Ellie

Eleanor McHugh
Games With Brains
http://slides.games-with-brains.net

 

[Marnen Laibow-Koser]

Never hire a computer scientist if you can get a maths, physics or
philosophy grad instead

Yup. Or music.

Ellie

Best,

 

[Eleanor McHugh]

=20
Yup. Or music.

Well I've known very few serious coders who didn't have a strong =
interest in music of one sort or another


Ellie

Eleanor McHugh
Games With Brains
http://slides.games-with-brains.net

 

[Aldric Giacomoni]

I've just been reading this list forever and knew it existed. I had an
unfair advantage.

Lazy evaluation was a popular topic in Ruby circles sometime back. That
was when Lazy.rb was invented. I looked into it quite a bit while
writing this old blog post:

http://blog.grayproductions.net/articles/infinite_streams

James Edward Gray II

Time to get some more reading underway. Oh... And did you know that the
lazy.rb file/gem is actually mentioned in "Ruby Best Practices" ?
Figures that ruby-forum and the book would act synchronistically for
me..

 

[Todd Benson]

Never hire a computer scientist if you can get a maths, physics or philosophy grad instead

Don't want to hijack (these are all good qualities by the way, but
with a sardonic tone

Maths grad: F equals MA if the axioms are founded
Phys grad: F does in "fact" equal MA no matter what
Philosophy grad: F equals MA only when it must
Engineering grad: F sometimes equals MA, but that's not the crux of the issue

 

[Rosalind Mitchell]

osophy grad instead
=20
Don't want to hijack (these are all good qualities by the way, but
with a sardonic tone
=20
Maths grad: F equals MA if the axioms are founded
Phys grad: F does in "fact" equal MA no matter what
Philosophy grad: F equals MA only when it must
Engineering grad: F sometimes equals MA, but that's not the crux of the i= ssue
=20

Cultural studies graduate: Bourgeois hegemony constructs F as an
arbitrary signifier of MA.

I'll get my coat.

Rosie

 

[Eleanor McHugh]

=20
Cultural studies graduate: Bourgeois hegemony constructs F as an
arbitrary signifier of MA.

Ah, so that's what cultural studies is


Ellie

Eleanor McHugh
Games With Brains
http://slides.games-with-brains.net

 

[Marnen Laibow-Koser]

Don't want to hijack (these are all good qualities by the way, but
with a sardonic tone

Maths grad: F equals MA if the axioms are founded
Phys grad: F does in "fact" equal MA no matter what
Philosophy grad: F equals MA only when it must
Engineering grad: F sometimes equals MA, but that's not the crux of the
issue

Hmmm...

Computer science: F = MA, but simple multiplication isn't OO enough, so
let's make an AbstractForceFactory...
XP: F = 3 always. When I need F to equal MA, I'll write a different
test.
Music: F is a M3rd below A.


Best,

 

[Todd Benson]

Hmmm...

Computer science: F = MA, but simple multiplication isn't OO enough, so
let's make an AbstractForceFactory...
XP: F = 3 always. When I need F to equal MA, I'll write a different
test.
Music: F is a M3rd below A.


Best,

You should include differences in frequency That was a pretty cool
spot, though.

Todd

 

[Gregory Brown]

Time to get some more reading underway. Oh... And did you know that the
lazy.rb file/gem is actually mentioned in "Ruby Best Practices" ?
Figures that ruby-forum and the book would act synchronistically for
me..

James does know that because the chapter in RBP was based off the blog
series he just linked to

 

[Aldric Giacomoni]

James does know that because the chapter in RBP was based off the blog
series he just linked to

Alright, so I'm a n00b ;-) I turned two more pages to see his name show
up.. I'll just be quiet until I'm done with the book