Download pointsconvexhull.mw

Perhaps what we need is some compound complexhull that can join the points.  In any case how about this attempt which isn't perfect by any means.

By the way To ADMIN - insert contents does not work - the link is just inserted, would be much better if it worked

Could I sub local for global in the proc?  Sub the variable then sub global back to local?  Using subs only, is that possible? 

Also still haven't been able to resolve subing i<50 using subs Error, `=` unexpected unless it works in newer versions.

Thanks, but the maple.exe mem usage reported by windows task manager is still higher than in should be, I'd like to modify this value to it's initial start without closing Maple (if there is a way).  Unfortunately I think it has something to do with the way Windows allocates memory as opposed to Maple which has no control over how Windows handles the memory.  If there was some sytem command ... maybe? ...

I recall a problem with Maple and the java machine which caused problems if you had too much memory (>2Gb) someone recommended to enter maxheap=256m in your launch.ini file and maplesoft tech support mentioned you could enter maxheap=700m and lower the value if problems still occur. 

If I check the total Maple's memory inside Maple using kernelopts

add(i,i=kernelopts(memusage)[..,3]);
                                            1355812

I usually on average on an empty sheet get that value.  But it doesn't matter if I open new worksheets and close all other old ones.  maple.exe in the task manager sits unusually high.  They fixed some memory issues from Maple 11 to Maple 12.  Especially the one where restart failed to completely empty arrays, the empty arrays still had allocated memory to them and so they had to be manually forced to 0 by a loop.  This was found by assigning a value and pointing it to an address then after restart check the address location which still contained the value.  (That was fixed by Maple 12)

Currently my maple.exe is showing 305,144 K even though I've opened a fresh blank worksheet and closed all others.  That should not be.  I don't think this is as bad in Maple 15 but I think it is still there, also I think they've even managed to reduce the kernelopts(memusage). 

Any tricks to empty the memusage on mserver.exe?

I think this is/was might still be, a memory usage problem with maple.  Although memory usage has been improved in Maple 15 quite a bit. 

For Maple 12, if the memory usage of mserver.exe and maple.exe approach 1Gb (I currently have 2.5 Gb), Maple likes to freeze.  I don't know if there is a workaround for that.  If there is, or even if there isn't, I'd would like someone to explain why that happens.  I would also like to know how to reduce the memory usage reported by windows task manager, I'm sure there should be some way but it would most certain help to free up some memory in that way.

It seems you are experiencing the same problem in Maple13.  Check your task manager to see how much memory usage the file is using.  It appears that if Maple starts using a little less than 1/2 the total RAM memory then things get sticky.  Maybe I'm wrong but I hope we can test that theory, twice today that's happened to me and I've been meaning to post a message regarding that.  Then I read your question which sounded similar. 

Any thoughts on the reasons?  And can someone test my theory?

Find replace only searches for items created in text mode.  If it was created in math mode it will not find it. 

I recently requested in the Maple 17 wish list exactly that.  However, Maple's help explicitly states that, and I will re-iterate here, The Find feature does not search content in 2-D Math notation. which is, at times, unfortunate.

Incidentally I came across this http://rosettacode.org/wiki/Constrained_random_points_on_a_circle and a lot of code exists for different languages.  Sadly Maple is missing.

I thought it could be done like this

a := []:
while nops(a) < 100 do
  ba := (rand(-15 .. 15))():
  bb := (rand(-15 .. 15))():
  b := evalf(sqrt(ba^2+bb^2)):
  if b <= 15 and b >= 10 then a := [op(a), [ba, bb]] end if:
end do:

pointplot(a,axes=box)

There are perhaps a myriad number of ways to accomplish this.  I'd like to see other variations.  I used rand and they asked from a uniform distribution.  Are they the same? 

And also how about my scatterplot about the circle? 

Not sure what algorithm Maple uses but you could use showstat() to try to determine which one.

showstat(LinearAlgebra[MatrixInverse])

I remember that one.  But I'm not seeing how to animate the object with a stationary point of reference for the color scheme.  Do you mean set the orientation values into the color scheme somehow? (something I'm not really sure how to do)

 **edit - add

Actually I think I see.  Using your example in your referred post and changing it to something like

animate(plot3d, [f, 1 .. 100, 1 .. 180, color = [proc (x, y) options operator, arrow; 1-(1/36000)*A*f(x, y) end proc, proc (x, y) options operator, arrow; (1/200)*f(x, y) end proc, 0], orientation = [A, A]], A = 0 .. 360, frames = 100)

I still need to work on it though, it's not quite right.

Yes it is in the maple help.

If you type ?relerr , Maple's help searches for it as a Topic as default where relerr will not be found.  Switching the search for Topic to Text will have found you the answer.

Usually if one does not find it under Topic it is good practice to do another search under Text.

@Joe, actually using RandomTree with showlabels=true.  but I like your little proc

Thanks to both for the help.

@ Robert for your last one, unless I do something like this which produces a non expected result

G := Graph({{a, b1}, {a, b2}, {b1, c1}, {b1, c2}, {b1, c3}});
DrawGraph(subs(b1 = b, b2 = b, c1 = a, c2 = c, c3 = b, G), style = tree, root = a)

                    a
                    |
                    b
                /    |   \
             a      c      b
             |
             b

but I would expect the return to be

                       a
                     /   \
                   b      b
                 /  |  \
               a   c    b

In a general sense, yes.  You'll have to modify one to your liking but you can thank gkokovidis from an earlier post for pointing out binarytree. 

Check maple help ?binarytree

That's a big ooops.  It's best to talk to Maplesoft customer support and explain your situation.

Here is one way

zip(`*`,[R_DC_total-sek],[R_AC_total-sek]);

I've never seen that in Maple before. 

I have seen that somewhere else, where the fonts weren't available and all that was displayed were square boxes ... I think it might have been in google translator when I was copying some translated language into word but I didn't have the correct fonts or something like that.

This appears to be somewhat similar, but I can't explain why when you execute a command, things disappear.  Did you happen to skip any install steps?  Had to ask, but I'm not sure if there are steps to skip in Maple 15.

Checking google "characters appear as square boxes" brings me here http://support.microsoft.com/kb/159418 - Characters appear as square boxes in printed document in Word 97 which suggests extended characters (greek symbols) is using a driver that does not support unicode characters. ...

I'm not sure if that was any help.  Perhaps someone else has a better idea of what's going on.

I have converted your answer to a new question as it doesn't relate to your original question in the thread.

Format -> Styles -> select C Maple Input in the style list -> click Modify and change color as desired.

That was for Classic Maple which I believe you are working with.  For Standard Maple it is a similar process.  Observe the style being used from the Select paragraph style indicator near the top left of the worksheet, the default is C 2d Input and use that style to modify.