## dharr

Dr. David Harrington

## 2820 Reputation

17 years, 269 days
University of Victoria
Professor or university staff

## Social Networks and Content at Maplesoft.com

I am a professor of chemistry at the University of Victoria, BC, Canada, where my research areas are electrochemistry and surface science. I have been a user of Maple since about 1990.

## improvements...

@Ronan I edited my original answer with an improved code. Your code agreed with the Matrix. This may be useful in my work, so thanks for introducing me to the Boole-Mobius transform.

## possible bug...

@Carl Love  To get the same output as Ronan I needed to switch jm and h in the updates line to become:

(im, istep, h, jm):= Scale2~([im, istep, h, jm], [-1\$3, 1])[]

Not sure if this affects speed because I know modular was updated after the version I have (2017)

## autocompile...

@Ronan I usually use Compiler:-Compile when I'm debugging, since there are many limitations about what Maple code can be compiled, but once I know it does compile then you can just add option autocompile after the proc() and the compiling will be automatic on first execution (and so the procedure can be used in a module or package, and the dll will be generated automatically).

## floating point issue...

@student_1 Yes, fracdiff(v(t), t,0) gives t but fracdiff(v(t), t,0.) gives 0. The solution is to use seq(fracdiff(v(t), t,alpha/2),alpha=-2..3)

## plot...

@MajorMax So this is just the plot command

plot((1+ln(x))/x,x=-5..5,view=[-5..5,-5..5]);


## worksheet looks better...

@nm There are many Computer Modern fonts on my system (I use Scientific Workplace) and I don't know which are which - I just chose cmr12 and cmr16 at random, but cmbxti10 looks more like what you want. The above x may just be the standard one.

P1 := plot(x^2):
P2 := plot(x^2,labels=["x","y"],axesfont=[cmr12,roman,16],
labelfont=[cmbxti10,roman,24]):
plots:-display(Array([ P1, P2 ]));


gives (snapshot from export to .pdf

Latexfonts.mw

@Earl  You/re welcome. As you probably realize, if the control point just goes  x[1] = pts[2][1]..pts[1][1] you will just get the centre part with ellipses in the quadrilateral, which you asked about in a separate question..

## no offense...

@mmcdara  Not at all - I expected someone could help out if that wasn't enough.  It seemed a question about why dsolve,series didn't work, and as is often the case the OP's Maple background wasn't very clear..

## tips...

I'm out of time these days, but had a quick look. I didn't check the eqns in detail, so can't comment on the method, but didn't see anything obviously wrong, except that "line" is in the plottools package, which wasn't loaded. I just tried regular solve, without the parametric option, but still lost connection with the kernel, which shouldn't happen. So my two tips would be:

Change the floating point numbers like 0.5 to exact 1/2 etc, since solve is for symbolic solutions (maybe solve would do this internally, but it is better to be sure and it is anyways good practice).

Rearrange the tangent equations to remove the denominators so a/b=c changes to a=b*c. Maple's solve is very good for polynomial systems, so that may work better.

## never zero...

@Axel Vogt  Some would say it is zero at x = infinity (complex infinity).  I think this is fairly standard when talking about poles and zeros.

## \mathrm in math mode...

@ecterrab I agree with @nm . The journals I use request \mathrm inside math mode when typesetting equations. I guess it would be \textrm outside.

## a variation...

Here's a variation where one of the coefficients becomes the parameter to vary. Conceptually simpler perhaps, but what the variation leads to and the flexibility is a bit more obscure.

Pencil2.mw

## error?...

I just copied the output of DirectSearch to bypass that - then it seemed Pen1 should have been Pencil at the point highlighted in red. Then your ellipses work as you describe. But I don't understand what else you want to do, so I'll leave that to someone else.

Pencil.mw

## not in orthopoly...

Note that LegndreP and JacobiP are not in the orthopoly package (but P in that package is related).

## ilog2...

@max125  If you want the nearest integer then ilog2(8) works, so it is interesting that log2(8) doesn't.

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