What is the command which returns the length of a list? i.e. length of [1,2,3] is 3 ? More importantly, please tell me where in the help menu this command is listed. Thank you.

I've created a new blog entry concerning what I think might be an idea worth consideration:     slide rule

... I doubt that there has ever been a better way to learn the relationship between numbers - and even mathematics in general - than the slide-rule from days-gone-by, and the ability to plot functions using modern computer technology. For the young people here who may not have ever used a slide rule, below is a link to a virtual slide rule:     virtual slide rule

I wish, and think...

Here is the article. I wrote this as a blog entry, and felt it was better to leave it one place rather than duplicating it. Besides, I don't know how to delete a blog entry. A cheap way to earn five points; however, my next page addition—in the works—to this book will be recompense.

Occasionally it is necessary to temporarily assign a global flag to perform an action. Consider, for illustration, a procedure that returns the inert form of a procedure. We want it to be able to work with procedures that are local to modules. To do that, we need to temporarily assign the kernel flag opaquemodules to false.

GetInert1 := proc(p::uneval)
local opacity,inert;
    opacity := kernelopts('opaquemodules'=false);
    inert := ToInert(eval(p));
    kernelopts('opaquemodules'=opacity);
    inert;
end proc:

Here is a small module to test this on:

Hello, I need to find relative extrema of an expression with inequalities. e.g. extrema(xi^2-x1^2-x2^2-xp^2-y^2,{xi-x1-x2+xp^2<=y^2},y); extrema command is not able to compute with inequalities constraints. Could you help me please? Thank you. Vladimir

Here are some possible bugs or limitations that I have come across while working with Tensors in the new physics package. I have done best of my efforts looking into the documentation, but it is still possible that the bugs I am listing are not bugs at all but outcome of lack of my knowledge in using Maple. My intention of creating this blog is to not to criticize but to help the Physics package development team in making updates. I appreciate their efforts for developing a much needed package for areas like fluid mechanics, continuum mechanics, theory relativity etc. Platform I am using: Maple Ver 11.01 on Mac OS X 10.4.10

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.

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):

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

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?

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!

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?

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 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.