A note added: Although the coding below is correct, it has clearly been superseeded by the following two entries contributed by acer: Entry 1 and Entry 2 in the blog entry Tip: Transpose a pair of indices of an Array. Yesterday I wrote about a method to index an Array, using a procedure of the type `index/method`. Below, using the same sort of procedure, a method for permuting the indices of an Array is given (please feel free to suggest improvements; probably, the else-statement may be written more concisely):

Sometimes it can be very useful to know the indices of entries (of an Array) which obey some conditions. The following procedure (which works for any Array) makes this possible:

`index/makeIndex` := proc(indices::list,array::Array,value::list)
	# Retrieving from the Array
	if nargs = 2 then return array[op(indices)]: end if:
	# Storing in the Array
	if nargs = 3 then array[op(indices)] := indices = op(value): end if:
end proc:

An example: For Array A find the set S of indices of entries being positive integers, using as an intermediate step the Array B with entries of the form "indices = value":

I am just getting started with Maple TA for Calc III. I am trying to solve LaGrange multipliers. When the solve command returns multiple sets of answers, how do I extract the specific values for the subs command? $f=xyz; $q=x^2+2y^2+3z^2-6; $g=maple("f+mu*$q"); $exp1=maple("diff($g,x)"); $exp2=maple("diff($g,y)"); $exp3=maple("solve({$q,$exp1,$exp2},[x,y,mu])"); $ans1=maple("subs({x = ????,),y =???? )},$f)"); $ans2=maple("subs({x = ????,y = ????},$f)"); The question marks are where I am lost.

I'm finally going to start my MaplePrimes blog, and I will post answers to some of the questions I get about the areas with which I'm familiar. Most of time, I get asked about 2-D plotting. Some of the information here may be repeated from forum comments, but hopefully, this will make it easier to find. Unfortunately, my participation on MaplePrimes comes in spurts, as I try to find time between my other tasks, such as developing features for new releases. I tend to rely on the many Maple experts on MaplePrimes who very competently answer most questions that arise. I will, however, try to be diligent about adding a new tip at least once a week. Let's see if I can live up to my promise and get beyond this first post!

Hi, I am fitting experimental data DATA(t) to a MODEL(t) with LSSolve. What would be the shortest way to plot the residuals(t)? Thanks, Evgeni

I've downloaded and installed the new Vista ready version of Maple 11 (11.01) and few things are curious. It installs something called the "Maple 11 Reader Beta". Not sure what this is or what it is intended to do, but if it is a Maple runtime, then that is very interesting. We only have one Vista machine here in my office and the reader doesn't actually run on it so I can't really tell what it does. Which leads to a warning, the reader is failing because of a problem with my previous install of Maple 10. I had installed Maple 10 using the "run in XP compatibility mode" workaround. So before I went to install the new version I tried to uninstall Maple 10. But, I forgot to set the Maple 10 uninstaller to run in compatibility mode before I ran it, and it blew up. So the uninstall of Maple 10 failed part way through.

Please replace this text with the link to your file. The link can be found in the File Manager Hi, I'm having the nastiest time trying to get a plot from with DEplot3d. I suppose it's not really necessary to look at the whole maple file, but just this part: DEplot3d({de, w(t)= diff(z(t),t),D(x)(t)=diff(x(t),t), D(y)(t)=diff(y(t),t)},{x(t),y(t),z(t),w(t)}, t=0..2*Pi,[[w(0)=P,z(0)=0]], scene = [x(t),y(t),z(t)]) I'm trying to plot the solution to a second order diffeq, where x(t), and y(t) are known. Any help would be appreciated...I've been racking my brain for hours on this stuff

For double-precision ("hardware") real and complex floating-point operations on Matrices, Vectors, and Arrays Maple makes use of its external-calling mechanism to get to compiled code. A great deal of such compiled code for array operations requires what are known as Basic Linear Algebra Subprograms (BLAS). The BLAS libraries provide support not only directly for Matrix-Vector arithmetic but also indirectly in other external compiled libraries used by Statistics, ArrayTools, LinearAlgebra[Modular], etc.

Not sure if this is known or not, I couldn't find any reference to it. If you have a Maplet that you serve over the Internet using MapleNet, if the Maplet code has a trailing comment character - # -, then the Maplet won't display. You get the unhelp error message: "Exception is server did not return a correct Maplet Definition. Results were" It's a trivial problem once you find it, but finding it was not trivial. For the MapleNet developers. Take any Maplet, add a new line at the end of the file, put a comment character at the start of the line. The Maplet will not work. You can add the comment char to the .maplet file or to a .mw that is then exported. Happens in MapleNet 10.5 and MapleNet 11.

Just a thought for my day...

In a system which, by default, evaluates the arguments of function calls it is little strange to make a habit of using an unevaluated function call as a data structure.

Passing around such an object may result in unwanted evaluation of the stored data.

Can someone please explaint to me why this isn't working and some possible corrections. Any help would be greatly appreciated! I'm trying to solve 2 equation and 2 unknowns. Below is the code that I have... View 4496_instri.mw on MapleNet or Download 4496_instri.mw
View file details

I find that reading lots of help pages causes eye strain. A way of reducing this that works for me is to change the background color of the help pages from white to yellow. This can be done by setting HelpBGColor=255,255,224 in the ini file. On Windows XP the ini file will be found at C:\Documents and Settings\Joe User\maple9.ini or maple10.ini. For Maple 11, the file can be found at C:\Documents and Settings\Joe User\Local Settings\Application Data\Maple\11\maple.ini

Hello. This is not a question, but an answer. I have just installed Maple 11 under Ubuntu 7.04 Feisty Fawn and I thought I would share my experience. 1) Log in to an account with sudo rights. 2) Insert the Maple 11 cd for Linux. When asked about what to do with it, mount it. 3) Open a terminal and write cd /cdrom sudo sh ./installMapleLinux32 4) Enter your password. 5) For the location of the installation, I entered /usr/local/maple11 instead of the default. 6) After the installation (and the activation) is complete, I created two symbolic links as follows: on the terminal, write

Hello, I would like to use Socket package to get informaction from HTML page on Website. COuld you help me please? I need to get the part of HTML file to use it in my procedure. Thank you very much Vladimir

If one only wants numerical values in double precision for real arguments then Maple is quite slow, even for the quite typical case of index 1 or 0. A way is to use the GNU Scientific Library GSL as external source for this special cases or to compile the needed stuff into a DLL and use that through external calls. However I (once) wanted to have that as Maple code and translated Ooura's solution into Maple (which is not too complicated). The motivation was to have something fast for evaluating integrals over such Bessel functions. Putting the coefficients needed for the numericial approximation into global arrays this makes Maple as fast as GSL (almost, M9.5 did, M11 is somewhat slower for this approach) for this functions, if one uses hardware float evaluations 'evalhf' (=double precision).