MaplePrimes Commons General Technical Discussions

The primary forum for technical discussions.

Every year at Maplesoft, we continue to pursue our mission of making powerful computational mathematics easily accessible within a friendly environment. Maple 17 is no exception: Hundreds of new algorithms, from differential equations to statistics to signal processing, continue to keep Maple ahead of the curve. At the same time, a wealth...



The application center has undergone some changes.  I usually like to see if things are working properly.

There are currently problems with searching maplesim models.  Doing an advanced search under maplesim5 does not bring up all maplesim 5 models, such as

- Flow dynamics in liquid connected tanks
- Double glazed windows


The next issue is with regards to phantom applications that are there but not linked.  For example:  Advanced...

Mathematica 9 was just released Nov 28 which caused me, of course, to have a look to see what wolfram has done in way of comparing itself to maple. 

Perhaps we can discuss, compare, debunk, clarify some of their claims or perhaps dismiss the results altogether

Here is one speed comparison chart I came across.  Is it relavent?  It shows Maple 16 as the worst performer.

 

I have found very little help about the Generate command of the RandomTools package.

I also have minor gripes about the syntax. And what better way to deal with these than to voice them?

This is how I was able to generate random lists and random Matrices.

A list of 10 random integers between 1 and 100:

L := RandomTools:-Generate(list(integer(range=1..100),10));

      L := [47, 8, 46, 44, 9, 77, 59, 16, 1, 70]

 

As many of you know now the MRB constant = sum((-1)^n*(n^(1/n)-1),n=1..infinity).

Here are some equations involving various forms of that summation.

The first one involves convergent series and is too obvious. The others involve divergent series.

The last two, however, are new!

 

Let c=MRB constant and a, c~, x, and y = any number.

 

sum((-1)^n*(c~*n^(1/n)-c~),n=1..infinity)= c*c~.

evalf(sum((-1)^n*(n^(1/n)-a),n=1..infinity)) gives c-1/2*(1-a).

evalf(sum((-1)^n*(x*n^(1/n)+y*n),n=1..infinity)) gives (c-1/2)*x-1/4*y.

And it appears that

evalf(sum((-1)^n*(x*n^(1/n)-a),n=1..infinity)) gives (c - 1/2)*x + 1/2*a.

Just happen to come accross this wikiVS page of Maple vs Mathematica. 
http://www.wikivs.com/wiki/Maple_vs_Mathematica

I find it heavily biased towards Mathematica. 

The version 16 of Maple does not know the function "pow", it is replaced by "power". Nevertheless, the codegen[optimize] procedure still generates it!  Moreower, it's not optimal even to write poser(..., 1/2)  as, most probably, the function sqrt must run faster. 

  Here's an example: (the function being optimized just contains some nested square roots)

> iang10 := [codegen[optimize](Re(int11), tryhard)];
[ 2 t17

There are two interesting threads about definite integration on the usenet group comp.soft-sys.math.maple posted in the past few days.

The first thread is more about the wrong result coming out of Maple's int command when computing via its `MeijerG` method. Motivating examples there include

int(cos(t)/(1+t^k), t=-infinity..infinity);      # for k=10,12,14,...

The poster demonstrates using residues to obtain a terse result.

In the second thread the poster examines the ideas that the solutions involving RootOfs (as returned by the `ftoc` method) may suffer from numerical difficulties during floating-point evaluation and are unnecessarily complicated when re-expressed in terms of more standard functions (ie. allvalues, then simplification...).

For those interested, an existing `contour` method exists within `int`. It is not very strong however. One can examine its source using commands such as,

showstat(`int/definite/contour`);

showstat(`int/definite/contour/def1`);

etc.

See also Methods of contour integration on wikipedia.

Recently, I published the following paper.

"Calibration of a radiocarbon age", Nonlinear Processes in Geophysics, 19: 345–350 (2012).

The paper explains that all radiocarbon dates are inaccurate, due to an error in the handling of the statistics.

The paper has a Supplement, which includes a program to do the statistics correctly:

I guess there is a limit bug here somewhere.  With MultiSeries things are OK...

L:=(x*BesselI(k-1, x)+x*BesselI(k+1, x))*BesselI(-k, x);
L := (x BesselI(k - 1, x) + x BesselI(k + 1, x)) BesselI(-k, x)
simplify(limit(L,x=0)) assuming k>0;
0
with(MultiSeries): simplify(limit(L,x=0)) assuming k>0;
2 sin(Pi k)
-----------
Pi

BesselLimit.mw

This is a comment and warning to anyone in the United States using MapleTA 8. 

If you get login information using LDAP, MapleTA 8 gets the "employee number" from the LDAP data base  and displays it on the screen when a person is logged in.  After talking to our IT people, they acknowledge that this is a FERPA violation when using MapleTA in a lab where people can see screens of other people's computers.

Our IT people have contacted Maplesoft for...

MapleSim has seen a rapid evolution since its inception in 2008 as a multi-domain system-level modeling and simulation environment. Market response has been outstanding: Maplesoft has been working with an expanding list of key industry players such as AISIN AW Co., Ltd. and B&R,  while major customers like

Viewing an html application at the application center results in some problems which doesn't allow to view the application in it's html format.

I had responded to a maplesoft application where data to a .mw worksheet was no longer available and had asked them to find and fix it.

I would have hoped a response would have been put here to mapleprimes to find the data.  Unfotunately the data could not be found and the application was deleted from the application center. 

It was Analyzing Data files in Maple - Maple 10 and Maple Net - Nov 7, 2005

Here is the link http://www.maplesoft.com/applications/view.aspx?SID=1685 ...

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