Dr. John May

## 2351 Reputation

12 years, 272 days
Maplesoft
Guru

## Social Networks and Content at Maplesoft.com

I am a Senior Developer in the Mathematical Software Group and have been with Maplesoft since 2007. I am also an Adjunct Assistant Professor in the School of Computer Science at the University of Waterloo.

I have a Ph.D in Mathematics from North Carolina State University as well as Masters and Bachelors degrees from the University of Oregon. I have been working on research in computational mathematics since 1997.

My main research interests in are computational linear and polynomial algebra, especially numerical polynomial algebra. I currently work on the exact algebraic solvers as well as other subsystems of Maple.

## Plot command...

I had neglected to include it in the original post, but someone requested it, so here is the Maple code I used to generate the second set of plots.

```plot3d(
[(3/5-(3/100)*(1-2*t/Pi)^10*cos(20*s)-(1/2)*sin(t)^(3/5))*cos(2*s)   +(1/1024)*s^10*((2/25)*sin(2*t)+(3/100)*cos(16*t))/Pi^10,
(3/5+(3/100)*(1-2*t/Pi)^10*sin(20*s)-(1/2)*sin(t)^(3/5))*(sin(2*s)   +(1/1024)*s^10*((2/25)*sin(2*t)+(3/100)*sin(16*t))/Pi^10),
(11/5)*t/Pi+7/10-(7/10)*cos((1/4)*s)],
s=0..2*Pi, t=0..Pi/2, scaling=constrained, color="Khaki", grid=[225,225]);```

John

## @roman_pearce The plots for spaghetti we...

@roman_pearce The plots for spaghetti were not nearly as interesting.

## @alex_01 It wasn't too bad to set up all...

@alex_01 It wasn't too bad to set up all those buttons.  Most of the logic in defined in the central initialization button.  To actually create the grid of buttons, I just setup one of them and then copy'n'pasted it 48 times.

## Unfortunately, if the points are not in ...

Unfortunately, if the points are not in general position, I think you'll need to manually sweep the points to remove all the ones that sit (numerically) on the convex hull.

## Unfortunately, if the points are not in ...

Unfortunately, if the points are not in general position, I think you'll need to manually sweep the points to remove all the ones that sit (numerically) on the convex hull.

## @PatrickT Yikes!  I was only able t...

@PatrickT Yikes!  I was only able to test my code on Mac and Linux before I posted it and apparently it does not work on Windows with the zlib DLL shipped with Maple 15.  I am looking into a good workaround for Windows, and will post it when I fix the code.

## @Joe Riel Nice.  I had originally s...

@Joe Riel Nice.  I had originally started with a seq using =, but removing the assignment to p was needed to really make it work.

## @Alec Mihailovs Perhaps you meant: (**)...

@Alec Mihailovs Perhaps you meant:

```(**) a := 5*x^2-4*x+3: hh := v^x*a+v^x: collect(hh,[v,x]);
x  2      x        x
5 v  x  - 4 v  x + 4 v
```

Putting two names in the calling sequence for ?collect treats the second as a post-processing procedure:

```(**) a := 5*x^2-4*x+3: hh := v^x*a+v^x: collect(hh,v,cos);
x     2               x
cos( v  (5 x  - 4 x + 3) + v  )

```

## Need Something Harder?...

If you hunger for a bigger challenge, here is a new version of the quiz which allows 4 choices: ColorQuiz-new.mw

## @acer According to Wikipedia the color N...

@acer According to Wikipedia the color Navaho White refers to the background color of the Navajo Nation flag.  Of course, Wikipedia also claims that the X11 Color name Indian Red is named after the red laterite soil found in India.  Crayola, at least, decdided that the later might be racially insensitive and now calls it "Chestnut".

## @acer The Minecraft .schematic format is...

@acer The Minecraft .schematic format is a gzip file.  While Maple has ?StringTools,Compress that uses zlib, that stream compression format has different headers than a gzip file.  While trying to modify the output of Compress to have the right headers, I remembered Alec's post, and realized that zlib could read and write gzip files directly, and so I adapted his code to use Maple's installed zlib (and to work on non-windows 32 platforms).

As for the voxelization code, it should be relatively easy to pull out and modify, but it is fairly raw, and it could use a lot of polishing.

## @hirnyk ?opaquemodules brings up the ker...

@hirnyk ?opaquemodules brings up the kernelopts help page which does describe the option:

Specifies whether local members of a module are accessible outside the module. Setting this to false makes it easier to debug code that uses modules. The default value is true.

## @hirnyk ?opaquemodules brings up the ker...

@hirnyk ?opaquemodules brings up the kernelopts help page which does describe the option:

Specifies whether local members of a module are accessible outside the module. Setting this to false makes it easier to debug code that uses modules. The default value is true.

## replies...

@Axel Vogt  It would be pretty easy to modify this worksheet to track and graph multiple variables ?plots,dualaxisplot might do a nice job if you were tracking things on two different scales like weight and hip measure.

@pagan That is exactly what it means.  It is like a cross between an auto-execute region (?worksheet/documenting/setautoexec) and a ?MathExpressionComponent in that you can change it and your changes get saved between sessions and restarts. That makes it perfect for this sort application where you are tracking data over time.

## Video...

@hirnyk We hope to tape the invited speakers, and to post those videos some time after the conference.  We may also be able to post the abstracts from the poster session as well.

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