MaplePrimes - Maple 2023 Posts and Questions

How to concatenate Matrices?

Lukasz — Wed, 08 Apr 2026 15:56:00 Z

My question concerns such situation:

how to concatenate the following matrices:

and

????

Which Tensor index is allowed ?

Mapleliquid — Thu, 19 Mar 2026 17:18:17 Z

I want to give my Tensor a the index i with define (a[i]) , but it is not allowed. Can anybody help ?

thank you !

95% of memory occupied and several hours

Gabriel Barcellos — Fri, 13 Mar 2026 19:06:13 Z

Objective: Solve a system of two equations.

Obstacle: Generating these two equations depends on millions of previous combinations as well as derivatives.

In other words, we've reached the maximum limit that Maple on my computer can handle.

What would be better, to leave the equations aside or to upgrade my computer?

(1)

Download Maple_forum_test.mw

How to get Threads to use all avalable cores?

Mac Dude — Wed, 11 Feb 2026 05:34:38 Z

I recently got access to a 12-core Intel MacPro with 64 GB main memory. This motivated me to try parallel programming again, even though in prior years I have never been successfull. The project I am trying to do is particle tracking through a circular accelerator, an embarassingly parallel problem in the sense that you can track n particles in parallel through your machine for many turns and then gather up the results for analysis. The function describing the tracking is a 6-component polynomial function acting on 6-vectors and yielding a 6-Vector as a result. Each accelerator component (magnet, drift section, rf, ...) is described by such a function. I am simplifying this a bit here, but in the problem at hand this is what I am doing. The point is that each particle gets treated independently from the others, hence parallelization should be trivial.

Using an existing package (Lattice, which I published with Maple) as framework I set this up such that the tracking proc for n turns of one particle in the accelerator is a member of a module. This module is in the body of a proc and gets returned when the proc is called, essentially instantiating the tracking object and assigning it to a Vector with as many elements as I have particles to track. The tracking function returns a 6-Vector with the coordinates after all turns are complete.
A separate proc does the instantiation of all tracking objects, gives each one its particle number (from a Beam object it is being given) and sends it off using Threads:-Create. It then waits until every task is done (using Threads:-Wait) and assembles the result in another Beam object which it returns. Please refer to the enclosed Maple worksheet for how it is done.

This actually all appears to work. MacOS is 15.7.2 (Sequoia); Maple is 2023.2. The results are identical both parallel and serial.

The "interesting" result however, is that usage of the available CPU cores saturates at about 4. In the graph shown below, the green line shows the CPU usage of the mserver process, and it saturates between 400 & 500%, actually going down to 360% as more particles get added. 100% is one core, so I am never getting more than about 4 cores to work for me. Correspondingly, the no. of seconds per particle goes up from about 3 s (particle 1 to 4) up to about 15 s/particle, settling at about 10 s/particle as 12 particles are approached. Below is a graph against no. of particles (n) of running time (red), CPU time (dark blue), CPU usage (yellow) and # or mkernel threads (green).

Bottom line: I am only getting 4 cores out of the 12. Process limits of MacOS (ulimit -a) do not indicate any limit that would cause this (and I have had build jobs that would merrily use all 12 cores).

Is there a limit in Maple that prevents using all available cores? Am I doing something inefficient that could cause this?? This is the first time I actually got parallel operations in Maple to work, so I am happy about that, but my happiness is tempered by not getting it to work at the level I was aiming for. I did google around a bit and found some prior conversations on MP (mostly involving @acer and @Carl Love) about parallel threads which indicated that (a) environment variable OMP_NUM_THREADS should be set and (b) that numcpus can only be set at the very beginning of a Maple session (which I interpret as "right after firing up Maple"). Did both (and verified the settings were in) but no change in behaviour of this code; I only get four cpu cores to work.

Thanks,

Mac Dude

Parallel_tracking_attempt.mw

Edit: Added graph, fixed up graph.

Maple 2023 cannot find Java

Mac Dude — Sat, 10 Jan 2026 21:30:19 Z

I just installed Maple 2023 on a MacPro running macOS Sequoia 15.7.2. Update to latest .version and activation worked without a hitch.

When I try to run it from the Finder it immediately puts up a dialog saying something like "Java not found". There is a webpage by Maplesoft addressing this, but it is completely uninformative and unhelpful.

I can get Maple to run using the cli (in Terminal) opening the Maple 2023 .app file, at which point Maple (running the standard GUI) works just as one would expect. So it is not a crisis but I'd like to be able to open it through the Finder as well. The Maple .app folder appears to have all the Java stuff in it, and clearly it is somewhere.

Anyone seen and solved this before?

Thanks,

Mac Dude

The coordinates of a special triangle

minhthien2016 — Fri, 21 Nov 2025 03:34:58 Z

In space, how can we find the coordinates of the three vertices of a triangle that is neither right-angled nor isosceles, such that the coordinates of its vertices, the coordinates of the foot of an angle bisector, the length of that angle bisector are all integers, and the lengths of the sides of the triangle are integers?

I tried

https://drive.google.com/file/d/1xOMxTCv3lC9RiKpwazerQ3D6WxeXLwJ-/view?usp=sharing