## grrrrrrrr: a Fourier integral

by:
```  restart; interface(version);

Classic Worksheet Interface, Maple 12.00, Windows, Apr 10 2008 Build ID 347164

Int(1/(u^2+1/4)*exp(I*u*k),u=-infinity...infinity); value(%);

0

but

Int(1/(u^2+1/4)*exp(I*u*k),u=-infinity...infinity...```

## grrr: strange behaviour of 'assume'

by:
```This behaviour of 'assume' puzzles me ...
and it needed some time to locate it

restart; interface(version);

Classic Worksheet Interface, Maple 12.00, Windows, Apr 10 2008 Build ID 347164

assume(a::real);
#a:='a'; # activating removes the problem
f0:=x+a;
#a:='a'; # that would not help - since is in use?
assume(0<a);
f:=collect(f0,x);

...```

## undoing one form of symbolic root

by: Maple

In this previous post, an example is shown that demonstrates the potential problems that can arise following symbolic conversions such as from sqrt(x^2)  to x^(1/2).

Here x is an unknown symbol. The difficulties include the fact that, while `sqrt` can be smart about simplifying numeric values (eg. integers, rationals) the `^` operator has no such opportunity. Once the conversion from `sqrt`...

## subsop example

by: Maple
```> q := x^(1/2):

> type(q, `^`);
true
> op(0,q);
^

> subsindets(q, `^`, f->subsop(0=H,f));
Error, (in unknown) improper op or subscript selector
```

What's wrong with that last one? It's modelled on the first Example in the ?subsindets help-page.

Are there cases where...

## grrrr: improper integration, algebraic integrand

by:
```'Int(x^(k+v-1)/(1+x),x = 0 .. infinity)': '%'= value(%);

infinity
/          (k + v - 1)
|          x
|   ...```

## Broken help links / Maple 12 Classic

by: Maple
```I am missing the F1-help to work properly after highlighting words
at least for the following

invfourier ---> completely missing (it is in inttrans)
invlaplace ---> completely missing
invmellin  ---> completely missing
fourier    ---> MTM[fourier], but not inttrans

Parts      ---> completely missing (expect it in IntegrationTools)
Flip       ---> ImageTools[Flip], but not...```

## errr ... exponential integral ---> sum

by: Maple
```  restart: interface(version); Digits:=14:

Classic Worksheet Interface, Maple 11.02, Windows, Nov 10 2007 Build ID 330022

Ei(1,1/2*Pi*(1+2*k)):
%=convert(%,Sum);
subs(k=0,%);
evalf(%);

Pi (1 + 2 k)
Ei(1, ------------) = GAMMA(Pi k + 1/2 Pi)
2

Pi            Pi
Ei(1, ----) = GAMMA(----)
2            ...```

## vote on bugs

by:

This is a long shot, but I think Maplesoft should open up its bug database and allow MaplePrimes users to vote up or down on bugs, reddit style. This would provide direct feedback about which bugs really affect people. Behind the scenes you could cross-reference the votes with account data to get all kinds of useful information: like what bugs disproportionally affect new users, or what bugs annoy experienced Maple users the most, etc. This would allow you to focus attention...

by: Maple

The functionality to extend and augment the context-sensitive menus is quite nice. I especially like the submodule ContextMenu:-Test whose exports allow one to programmatically test the results and new menus.

But what about installing menus with items whose type checks relate to locals?

Here's a simple example.

> newCM[Entries][Add]("local to global", "convert(%EXPR,`global`)", `local`):
> newCM[Entries...

## magic legend

by: Maple

Maple 11.00, Standard GUI, worksheet mode.

plot(sin(x),x=-10..10,legend="__never_display_this_legend_entry");

It's magic. The LEGEND() call is present in the PLOT structure, but it doesn't get displayed.

acer

## 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;

## slightly strange strange plot behaviour

by: Maple

Does anyone else see the following strange behaviour in the Maple 11 plot engine?

I was acting in a Std GUI Worksheet, not a Document. (I use Maple for 64bit Linux, which may or may not matter.)

1) In this next plot below, a (superfluous?) solid triangle appears. It lies in a xz-parallel plane at y=-1, with vertices (0.0,0.0,0.0), (1.0,-1.0,0.4), and (1.0,-1.0,0.0).

plot3d(sqrt(1-y^2),x=1..2,y=-1..1,colour=red,filled=true,view=[-0..2,-1..1,0..1]);

## a small competition

by: Maple

In the admirable quest to make Maple better and stronger, and since so few people responded to the Suggestion to add a searchable bug database here on mapleprimes, here's another tack.

What are the fewest keystrokes that can make the TTY commandline interface of Maple 10.06 or 11 crash?

By crash I mean something like bus-error or segmentation-fault, stack-limit-exceeded, or lost-kernel-connection. I don't mean a runaway computation that simply consumes all...

## different parsers

by: Maple

I was mulling over an example that behaved differently when cut and pasted in a Document (2dmath input) and a Worksheet (1dmath maple input). The example was this,

M := Matrix([a]);
N := Matrix([b]);
(M.N)[1,1];
(M.N+N)[1, 1];

The last line of that, in Maple 11.00, produces the product of the list [1,1] and the addition M.N+N, instead of indexing into that sum's Matrix result as it does with 1dmath input.

Is that a bug? Clearly there are...

## design mistakes

by: Maple

In several comments on a post about a surprising failure of an attempted Maple calculation, subscripted names and indexed names are discussed as if somehow are naturally meant to go together. But the only reason that they are associated in Maple's Standard GUI's 2dmath is because Maplesoft chose to implement it this way. My own feeling is that subscripted names and indexed names should certainly not...

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