acer

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19 years, 135 days
Ontario, Canada

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These are replies submitted by acer

There are some alternatives which deal specifically with each axis separately.

For the horizontal (first) axis,

  xtickmarks = piticks

or,

   axis[1] = [tickmarks = piticks]

See also the Help page for tickmarks.

I got the impression that this talk was by a member of a team that is working on enhancements to that package's functionality, and that the video is showing current results of that. In other words, it seemed to me like a report on current progress, which might have attained since the last major Maple release.

This supposition seems (to me) to be borne out by the speech and text appearing between 33:00 and 37:00 in the video.

ps. The presenter works with ORRCA, and there are tie-ins between that group and development of Maple's RegularChains, etc. This is one of a few research groups which contribute to Maple. It's quite common for such conference talks to show current development.

@Eunsang 

1) You write of problems when you make the step timestep too large. You also write of wanting, "higer [sic] spacestep". Are you sure that you don't mean smaller?

1) What is the specific desired spacestep that you want?

2) Do you know what timestep you want to use? Or do you just want the smallest timestep for which the computation is quick enough, when using your target spacestep? How fast is fast enough?

3) Are you seeing aspects in the plot that seem qualitatively wrong to you, due to, say, overly coarse step sizes?

4) You wrote, "I tried to find the optimal plotting points by adjusting the timestep while maintaining the desired spacestep...". What does "optimal plotting points" mean, exactly?

5) Do you have concerns about the scaling in your system, or suspect numeric difficulties due to inadequate working precision?

6) Your constant values contain floats like 0.33 and 3.14.  Are those coarse approximations of 1/3 and Pi? Do your have more accurate values for any of the floats and, if so, any reason not to use them?

@Blanc 

restart;

kernelopts(version);

`Maple 2023.2, X86 64 LINUX, Nov 24 2023, Build ID 1762575`

f := (x, n) -> 2^n/(1 + n*2^n*x^2) - 2*x^2*(2^n)^2*n/(1 + n*2^n*x^2)^2;

proc (x, n) options operator, arrow; 2^n/(1+n*2^n*x^2)-2*x^2*(2^n)^2*n/(1+n*2^n*x^2)^2 end proc

Eq := factor(f(x,n));

-2^n*(n*2^n*x^2-1)/(1+n*2^n*x^2)^2

solve(Eq>0, x) assuming  n>0;

{x < 1/(n*2^n)^(1/2), -1/(n*2^n)^(1/2) < x}

solve(Eq>0, x) assuming  n=0;

x

solve(Eq>0, x) assuming  n<0;

{x < -1/(-n*2^n)^(1/2)}, {x < 1/(-n*2^n)^(1/2), -1/(-n*2^n)^(1/2) < x}, {1/(-n*2^n)^(1/2) < x}

Download s_k_2023.mw

@Gabriel Barcellos And yet you seem to be asking how you might make something occupy a common physical distance on different screens regardless of their respective resolution settings.

Your request contains a contradiction.

@Gabriel Barcellos Do you believe that you can control the resolution of other people's computer screens?

@Ronan The Vector(n) is also a call to the Vector constructor, as well as a type.

If you want to use it as a type, in an argument to the type command, then you need to keep it as that (literal) unevaluated function call and prevent it from evaluating and becoming an rtable data structure.

Try it instead as either
   ''Vector''(n)$1    # 2 nested pairs of single right-ticks, not quotation marks
or,
   'Vector'(n)
so that type receives the unevaluated function call in the argument.

Ronan_tp_ex.mw

@C_R When you first wrote your Question (and I replied) I overlooked the mention at its end about dsolve,numeric. Sorry.

If I'd realized that then I would not have suggested your 3rd approach offhand. I'd almost always prefer using odeplot rather than the extracted procedures -- if time/memory efficiency were especially needed, or if animations were the result. It's not just how odeplot efficiently uses/re-uses dsolve's the constructed piecewise interpolants; it's also basic stuff like not bouncing around to poll independent (time) values (that 1D plotting can do) without any the right constrained purposes, or crudely forcing regular spacing even when it doesn't help (ie. ignoring curvature) when using spacecurve + extracted dsolve procs, etc.

@C_R 

In your attachment the two animated portions don't interleave rightly, in the sense that both were created for t=0..10, and presumably are wanted by you as sync'd when combined. That's because they don't have the same number of frames; only one has 150 frames. The one with fewer frames is crammed into the front portion of the other. Are you aware of this?  Is that your question/problem?

Also, is there a reason not to use the background option of animate?

Is it a problem that the overall construction is too large in memory or structure size? Or for any of the three portions? If so then can you bear to have a slightly less smooth curve, as t gets large? If you don't need to export then could you animate via Explore instead, so that only one frame is constructed at a time and memory usage is reduced?

I'm not sure what exactly is your question now.

If this is a very large animation then I suggest that you try:
1) remove all output from the worksheet
2) export the animation to .gif, and attach that after the worksheet

Or, just do 1).

We might have to re-run it, but at least we can make progress on helping with additional aspects.

@salim-barzani You wrote, "you did a great job but why forget a code for finding the parameter automaticaly at the matrices, i didn't know where i should rename and say find thus parameter if you do that it will be so good and if you do odetest like this stuff just you can do it will be ultra hight level code".

I didn't "forget" anything. I may have not done all you hoped for, but I didn't forget.

Your phrases, "...finding the parameter automaticaly at the matrices" in unintelligible to me. How you want to use all this with odetest is unclear. I didn't do those additional things you see to want because your mere hints about their nature are insufficient for me to understand the precise goals.

It's not just that the explanation is insufficient. It's almost nonexistent.

If you properly and adequately explain what more you want to do with this then I might try it. Fragments of your own code which don't accomplish your task are not an adequate explanation.

Which two of names present in expression M are going to be used as the plotting variables in plot3d?

Note that (in addition to mistakenly trying to use B[1],B[2] as the procedure's parameters) your substitution list doesn't all match the actual names present in expression M. The number of them is not right. The pairings are not right.

We can't fix it properly without knowing/guessing which two are the dependent variables for the plot3d.

Do you want the spinning cube to get its snapshots with the same frame-rate as the traced objects (time-dependent spacecurves).

Without a specific example I'd be tempted to go for the third option.
[edit: when initally I wrote this I'd completely missed the detail that the OP was intending the spacecurves to arise from dsolve/numeric results. Sorry. With that knowledge I'd prefer the 2nd approach offhand, using odeplot for the portion involving such curves.]

Do you think that the time to construct the animation will be a concern?

@Jesús Guillera Please put any close followup queries on this here, rather than on a wholly separate new Question thread.

Duplicate threads get flagged as such, and may be deleted by a moderator.

@C_R Some results may be stored in commands below the level of the procedure(s) returned by dsolve, and that can even include evalf (which has its own special kind of remember table).

And there may also be procedures with option remember,system which means that there's a remember table but its results are more transient and can get cleared by a garbage-collection (which can be triggered by memory use amounts).

I put in that 2nd call that you've noticed, because the timing detail you've mentioned is interesting. It's not as much of a gain as one gets by slapping option remember on the very procedure(s) returned by dsolve.

It's been a while since I poked around those procs returned by dsolve, in a comprehensive study. I don't recall full details offhand, sorry.

ps. Side-topic: be super careful/wary of putting option-remember on the returned procs if you intend on using them with dsolve/numeric's parameters option. You'd need to use forget, when changing parameter values on the fly. (As someone here once joked: if you remember to remember then don't forget to forget.)

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