## ICCOPT II / MOPTA 07

by:
On Monday, Aug. 13, I will be at a big optimization conference at McMaster University in Hamilton, Ontario. It's the joint International Conference on Continuous Optimization (ICCOPT) and Modeling and Optimization: Theory and Applications (MOPTA) conference. I'll be running a session with three Maple-related talks given by Jan Bakus of Maplesoft, Andrew Curtis of the University of Western Ontario, and myself. If any of you are attending the conference (and I

## Specifying sample points for a 2-D plot

by: Maple
Here's a question I was asked very recently: "When creating a plot, is it possible to specify the points at which the input expression should be evaluated?" The answer is "yes" for 2-D plots, and this is done with the 'sample' option. Use the command plot(f(x), x=a..b, sample=[x1, x2, ..., xn]) to have f(x) evaluated at points x1, x2, ..., xn. Note this produces a plot that includes points with x-values x1, x2, ..., xn. To produce a plot that contains only these points, you need to add the adaptive=false option as well.

## evalhf and module export question

by: Maple

The first example below seems OK. But, should I be expecting the different behaviour in the second example?

> restart:
> p := module() option package; export foo;
> foo:=proc(x) x; end proc;
> end module:

> foo := proc(x) cos(x); end proc:

> foo(3.2);
-0.9982947758

> p:-foo(3.2);
3.2

> evalhf(p:-foo(3.2)); # OK
3.20000000000000018

> restart:
> p := module() option package; export sin;

## Maple v Mathematica

Dear all, I recently had to solve the following integral: A:=(x,m)->(-m^2-2*x*m+1)/(sqrt(x)*sqrt((m+x)^2-1)*(x+sqrt((m+x)^2-1))); IntegralA:=(m)->Int(A(x,m),x=0..infinity); When I used evalf(IntegralA(1)); I get -2.828427125 But when I use int(A(x,1),x=0..infinity); to get a symbolic answer I get a complicated expression involving the function MeijerG function. Mathematica, on the other hand gives -2sqrt(2) exactly for the symbolic value. Does anybody know why? I'm curious even though the decimal values are the same. I was using Maple 11 and Mathemtica (I think) 5. Regards, Drew

## Numerical method used in implicitplot3d

Hi folks, When I use a command like: implicitplot3d(f(x,y,z)=0,x=...,y=...,z=...) obviously maple has to compute all the points in the given range which satisfy the equation. Does anybody know which numerical method it uses to do this? Regards, Drew

## animate two sphere around a circle

This is what I have so far, I would prefer that the globe be animated with the animate code, also if there is a way to tilt the globe slightly. I also want to be able to have the moon and sun go around the globe as it is rising and falling. While the Sphere is rotating. I want to try and do this with animate or rotate commands Packages: with(plots):with(plottools): Globe: sphere: globe:=sphere([0, 0, 0], 1/3): display(globe,scaling=constrained,style=patch,axes=none): animation: globe := sphere([0,0,0], 1/3): n := 80: plt[0] := globe: for i to n-1 do

## animate a sphere

Maple
I am trying to animate a sphere/ so that it kinda looks like the globe rotating. This is what I have so far. Also if any body knows how to tilt a sphere so that it is on an angle. that would greatly help. with(plots):with(plottools): globe:=sphere([2.0, 1.5, 1.5], 1): display(globe,scaling=constrained,style=patch,axes=normal):

## puzzling substitution

by: Maple
Here's a substitution that briefly surprised me. It makes sense once you understand what is going on.
```subs(true = false, proc() local i; for i to 3 do true; end do end proc);

proc()  end proc
```

## Massive parse()-ing

by: Maple
A little under two years ago, I started working on a little project we have here at NCSU. I should perhaps devote another blog entry to discussing that lovely little project... Anyway, there's a lot of Maple code in this project (as it is based in Maple), and I've had to untangle and understand what multiple programmers have done over the years. Last year, I came across one piece of code that I thought was exploiting a bug in Maple: We would take a long string of commands and parse the entire string with a single `parse()` command. I could never get a Maple worksheet to reproduce those results obtained from piping the command into Maple from the command line. Weird, no?

## Silly fopen() oversight (bug)

by:
It's just a silly, simple thing, but I'm going to call attention to it anyway: `fopen("file", w);` Produces the error message "Error, (in fopen) file mode must be READ or WRITE." This is incorrect. The file mode must be READ, WRITE, or APPEND. Like I said: silly, but worth noting.

## Maple Quilts

by: Maple
Waterloo Region, where our head office is located, has been called "The Quilt Capital of Canada". So a couple of years ago, I'd created a worksheet to generate a traditional "Log Cabin" quilt. I've made some minor updates to the example and added a "Trip Around the World Quilt". Having made a few quilts by hand myself, I can definitely say that it's easier to create a Maple one!

## MapleNet - library use

by: Maple
I would like to set up library(s) of routines that can be accessed as part of MapleNet applications. MapleNet applications are prevented from doing file i/o unless you specifically "unprotect" your server. Is there a way to set up libraries on my web server to safely get around it? Or is there a way to include my library routines while I'm building my maplet application, without copying and pasting in the source?

## 3d Complex Plots

by: Maple

Here are more 3D Strange Attractors, the formula I used is a PickOver which is described in my last post, every plot has 10000 iterations(it could be more), you will find that some plots has shape of a Galaxy which I found very interesting because it is a relatively simple formula!! What more things could be so simple!!?? Gravitation:

Gravitation(different angle): Tornadoe: Tornadoe(different angle and coloring): Galaxies: Galaxies(different angle): Constelation: Thats all for now... If you have a question, suggestion, or an idea for an algorithm, write to me. Scasbyte. (scasbyte@hotmail.com)

## Maple 11 Tensors in Physics Package Wish List

by: Maple
Maple 11 has included indicial notation capability to its new Physics package. This is a good start in performing tensorial calculations using Einsteinian summation convention. However, I wish that Maple further adds the following capabilities to make this package of practical use to folks involved in tensor analysis. This wish list is based upon my personal experience in using tensor analysis for continuum-mechanics and is in no way representative of the community involved in other fields like the theory of relativity. 1) Both covariant and contravariant indices are denoted in subscript. Including the convention of posting counter and covariant indices in super and subscripts, respectively, will help to improve the readability of the printed results.

## Strange Attractors

by: Maple
Hi! I'm ScasByte welcome to my MaplePrime blog.

If you are interested in 3d Strange Attractors but you don't know how to create it here I can show you how, create Strange Attractor is actually very easy, if you are new to Maple then you might this very useful.
Here is a link to the first 3d Strange Attractor(the most simple of all) a PickOver.

Here is the code to generate a PickOver:

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