gmane.comp.mathematics.maxima.general

wxMaxima "Insert Image" command

Berns Buenaobra — 2013-05-21T08:11:44

I have the same observation on my worksheets. So what I do is after I
evaluate everything I export that to a HTML so I have all images and the
symbolics, numerics as well.

Unfortunately the editable worksheet will always just give you the links
the image path and filename and thats it. So in a way we could say that it
does not really "embeds" the image. This maybe a known limitation we
probably need to accept.
Its easily done in MathCAD and is truly embedded but thats commercial stuff.

Regards,
Berns B.
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Re: ratsimp and many terms to collect. 3 lines.

Bill Wood — 2013-05-20T18:55:06

Interesting; this provides something for free:

(%i8) change(x^a*x^b*z^r);

(%o8) x^(b+a)*z^r
(%i9) change(a^x*b^x*z^r);

(%o9) (a*b)^x*z^r

BTW isn't this a response to "Simplifying x^a*y^a to (x*y)^a" or am I
missing something?

Re: ratsimp and many terms to collect. 3 lines.

Richard Fateman — 2013-05-20T18:15:07

you can try something like....

matchdeclare([a,b,c,d],true);
tellsimp(Power(a,b)*Power(c,b)*d,  d* Power(a*c,b));
change(z):= subst("^",Power, subst(Power,"^", z));

change(x^a*x^b*z^r)   for example.

Re: Simplifying x^ay^a to (xy)^a

Stavros Macrakis — 2013-05-20T15:21:16

Derka, nice trick, using logcontract in two different regimes.

A few additional minor comments on the code:

* There is no reason to put _s and _z in the block variables. They are
local to their lambdas already.
* If you *do* want to define exp_log_to_power locally, you need to add
local(exp_log_to_power) after the block variable declaration.
* But I agree with Barton that you might as well make it global.  If it is
strictly a helper function, useless for anyone else, you can call it
something like expcontract_exp_log_to_power.
* It's good practice to always quote symbolic constants: logexpand: 'super
* You probably want to restrict to something more than just not-atom in the
scanmap lambda; logcontract(log(...)) won't do anything useful for function
calls, subscripted variables, etc.  It won't do any damage either, but by
that reasoning, you can just remove the 'if atom' clause.  On the other
hand, you probably want to protect against constructing log(0) in e.g.
expcontract of [0] or atan2(x,0).

Re: Simplifying x^ay^a to (xy)^a

Barton Willis — 2013-05-20T14:12:25

You might consider:

(1) placing the assignment  logexpand: super  inside a block--your code globally alters logexpand

(2) moving the definition of exp_log_to_power to outside the body of expcontract--the definition of
     exp_log_to_power is global--it gets redefined everytime expcontract is called.

And by the way: if you like the leading underscores on variable, that's OK. But for this code, there is 
no need to wartify the variable names. Actually, I think that leading underscores makes code harder
to read, and it makes me more likely to make errors (one place _z another z).
 
--Barton

________________________________________

I have a idea (combined previous)

expcontract(_expr):=block([_z],
     exp_log_to_power(_e):= block([_s, logconcoeffp: lambda([_s],true)],
logcontract(_e)),
     logexpand: super,
     scanmap(lambda([_z],if atom(_z) then _z else (
         exp_log_to_power(exp(logcontract(log(_z))))
     )),_expr)
)$

expr: x^a*y^a$
expcontract(expr);
  ->  (x*y)^a

expr: (a^d*b^d+c^a*a^a)/(d^

Re: wxMaxima "Insert Image" command

Andrej Vodopivec — 2013-05-20T10:17:12

Inserted images are not supported in wxm files. You need to save the file
as a wxmx file. In this case the image is copied (not linked) into the
document (you can delete the original image and the image will still be in
the document)

Regards,
Andrej


On Sun, May 19, 2013 at 3:11 PM, Ronald Modesitt <
ronald.modesitt.835< at >gmail.com> wrote:

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wxMaxima "Insert Image" command

Ronald Modesitt — 2013-05-19T13:11:31

The wxMaxima "Insert Image" command is causing me some confusion. I am
assuming that "insert image" creates a link to a .png file which would then
be displayed upon opening the session file (.wxm) for additional work.

Upon opening the .wxm file and issuing  "evaluate all cells" wxMaxima
displays a text field with the .png file name from "insert image" command
but not the image. I would appreciate help in understanding how "insert
image" works.

I am using Windows Vista Business with wxMaxima 12.04.0,  and Maxima 5.28

Simplifying x^ay^a to (xy)^a

Derka Ladislav — 2013-05-18T18:23:12

I have a idea (combined previous)

expcontract(_expr):=block([_z],
     exp_log_to_power(_e):= block([_s, logconcoeffp: lambda([_s],true)], 
logcontract(_e)),
     logexpand: super,
     scanmap(lambda([_z],if atom(_z) then _z else (
         exp_log_to_power(exp(logcontract(log(_z))))
     )),_expr)
)$

expr: x^a*y^a$
expcontract(expr);
  ->  (x*y)^a

expr: (a^d*b^d+c^a*a^a)/(d^b*e^b+a^b*c^b)$
expcontract(expr);
  -> ((a*b)^d+(a*c)^a)/((d*e)^b+(a*c)^b)

Derka

Re: Regression in integration

Barton Willis — 2013-05-19T19:46:35

One more thing:

(%i1) integrate(x^n,x);

0> Calling (ASKSIGN1 ((MEXPT SIMP) ((MPLUS SIMP) 1 $N) 2))
Is n + 1 zero or nonzero?

nonzero;

<0 ASKSIGN1 returned $PN
(%o1)                               log(x)

The function asksign01 mishandles a return of $pn from asksign1 :

(defun asksign01 (a)
  (let ((e (sign-prep a)))
    (cond ((eq e '$pnz) '$pnz)
  ((member (setq e (asksign1 e)) '($pos $neg) :test #'eq) e)
  (limitp (eps-sign a))
  (t '$zero))))

--Barton

___

Re: Regression in integration

Barton Willis — 2013-05-19T19:30:50

I think the problem is with the return value for asksign:

(%i4) asksign(xxx^2);
Is xxx zero or nonzero?

nonzero;
(%o4)                                zero
(%i5) asksign(xxx^2);
Is xxx zero or nonzero?

zero;
(%o5)                                zero
(%i6)

This integral of x^n uses a defprop on mexpt (look in sin.lisp).  There is an asksign that always returns zero--that chooses the log option.

--Barton

________________________________________
From: maxima-bounces< at >math.utexas.edu [maxima-bounces< at >math.utexas.edu] on behalf of Raymond Toy [toy.raymond< at >gmail.com]
Sent: Sunday, May 19, 2013 11:42
To: maxima< at >math.utexas.edu
Subject: [Maxima] Regression in integration

I was looking at a message from Harry Christhian[1] about a bug in
integration, which I didn't quite understand, but I found the
following serious error:

(%i1) integrate(c/x^n,x);
Is n - 1 zero or nonzero?

nonzero;
(%o1)                              c log(x)

It doesn't matter whether you answer zero or nonzero; you get the
answer as if n = 1.

Regression in integration

Raymond Toy — 2013-05-19T16:42:57

I was looking at a message from Harry Christhian[1] about a bug in
integration, which I didn't quite understand, but I found the
following serious error:

(%i1) integrate(c/x^n,x);
Is n - 1 zero or nonzero?

nonzero;
(%o1)                              c log(x)

It doesn't matter whether you answer zero or nonzero; you get the
answer as if n = 1.

Ray

[1] Is it possible to directly send email to maxima-bugs?  Or should
only the bug tracker send email to that list?  Anyway, I think he's
saying integrate(c/x^n,x) returns -c/(1-n)*x^(1-n) but he wants
-c/(n-1)/x^(n-1).

Re: matrix multiplication

Zbigniew Komarnicki — 2013-05-18T13:35:17

Thank you very much. Now is OK.
 

Zbigniew

Re: Simplifying x^ay^a to (xy)^a

Barton Willis — 2013-05-18T10:55:22



I'm not aware of a function that does this.  When either a is explicitly an integer or when x and y are positive, Maxima's general
simplifier does (x*y)^a --> x^a * y^a . So if you wrote a function that does x^a * y^a --> (x*y)^a, the general simplifier would
sometimes automatically revert the change.

--Barton


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Simplifying x^ay^a to (xy)^a

Dominic Di Toro — 2013-05-17T16:14:17

Is there a maxima command that can make that simplification?

Simplifying x^a*y^ato (x*y)^a,

Essentially radcan in reverse

Thanks

DMD

Re: matrix multiplication

Leo Butler — 2013-05-17T21:50:32

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   From: Zbigniew Komarnicki <cblasius< at >gmail.com>
   Date: Fri, 17 May 2013 21:41:08 +0200
   Content-Type: text/plain; charset="us-ascii"

   Hello,

   I try multiply matrices, but te result is strange to me, see

   (%i1) matrix_element_mult: ".";
   (%o1)                                  .
   (%i2) matrix([A],[0],[0]) . matrix([W]) . matrix([E]);
    [ A ]
    [   ]
   (%o2)                            [ 0 ] . W . E
    [   ]
    [ 0 ]

   Why above result is not expanded? If I use braces around (see below) 
   then it works as expected, why? Is it a bug? What is the reason 
   for this behavior?

   (%i3) (matrix([A],[0],[0]) . matrix([W])) . matrix([E]);
    [ A . W . E ]
    [           ]
   (%o3)

matrix multiplication

Zbigniew Komarnicki — 2013-05-17T19:41:08

Hello,

I try multiply matrices, but te result is strange to me, see

(%i1) matrix_element_mult: ".";
(%o1)                                  .
(%i2) matrix([A],[0],[0]) . matrix([W]) . matrix([E]);
                                 [ A ]
                                 [   ]
(%o2)                            [ 0 ] . W . E
                                 [   ]
                                 [ 0 ]

Why above result is not expanded? If I use braces around (see below) 
then it works as expected, why? Is it a bug? What is the reason 
for this behavior?

(%i3) (matrix([A],[0],[0]) . matrix([W])) . matrix([E]);
                                 [ A . W . E ]
                                 [           ]
(%o3)                            [     0     ]
                                 [           ]
                                 [     0     ]


This not work
(%i4) expand(matrix([A],[0],[0]) . matrix([W]) . matrix([E]));
                                 [ A ]
                                 [   ]
(%o4)

Simplifying x^ay^a to (xy)^a

Dominic Di Toro — 2013-05-17T16:19:33

Is there a maxima command that can make this simplification?

Simplifying x^a*y^ato (x*y)^a,

Essentially radcan in reverse

Thanks

DMD

Re: Broken documentation

Rupert Swarbrick — 2013-05-16T22:54:16

The parse-info branch has the changes for Texinfo 5 merged in. I still
haven't spent enough time to check all the encoding stuff is exactly
right with the parse-info branch. When I have, I'll start trying to
convince you guys to merge it in :-)

Rupert
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Re: Broken documentation

Robert Dodier — 2013-05-16T16:20:03


Current state of master is that building docs w/ Texinfo 5 succeeds, but
the results are a little messed up. There is also a branch parse-info,
but I don't know how that works with Texinfo 5.

best.

Robert Dodier

Re: teaching Maxima logarithms

Raymond Toy — 2013-05-16T15:54:14

    Jorge> Very impressive, Barton!  I have two related questions:
    Jorge> 1. I found that the Maxima Manual mentions the optional variable %e_to_numlog:

    Jorge> When true, r some rational number, and x some expression, %e^(r*log(x)) will be simplified into x^r .

    Jorge> That sounds like what is required here (and essentially what Barton's function is doing).  However, I can't get this variable to work properly.  With it set to true or false, I still get:

[snip]

    Jorge> (%i95) %e_to_numlog : true;
    Jorge> (%o95) true

    Jorge> (%i96) %e^(y*log(10));
    Jorge> (%o96) %e^(log(10)*y)

As it says above, "r some rational number".  y is not a rational
number.  I think this only works if y is a rational number:

exp(4/7*log(10)) -> 10^(4/7)

Ray

Broken documentation

Camm Maguire — 2013-05-16T14:54:37

Greetings!  Is there a version of the documentation that builds with the
latest texinfo?

Take care,

gmane.comp.mathematics.maxima.general

wxMaxima "Insert Image" command

Re: ratsimp and many terms to collect. 3 lines.

Re: ratsimp and many terms to collect. 3 lines.

Re: Simplifying x^a*y^a to (x*y)^a

Re: Simplifying x^a*y^a to (x*y)^a

Re: wxMaxima "Insert Image" command

wxMaxima "Insert Image" command

Simplifying x^a*y^a to (x*y)^a

Re: Regression in integration

Re: Regression in integration

Regression in integration

Re: matrix multiplication

Re: Simplifying x^a*y^a to (x*y)^a

Simplifying x^a*y^a to (x*y)^a

Re: matrix multiplication

matrix multiplication

Simplifying x^a*y^a to (x*y)^a

Re: Broken documentation

Re: Broken documentation

Re: teaching Maxima logarithms

Broken documentation

Re: Simplifying x^ay^a to (xy)^a

Re: Simplifying x^ay^a to (xy)^a

Simplifying x^ay^a to (xy)^a

Re: Simplifying x^ay^a to (xy)^a

Simplifying x^ay^a to (xy)^a

Simplifying x^ay^a to (xy)^a