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MaplePrimes Activity

These are questions asked by Annonymouse


I am using a simple piece of code to generate Lie derivatives, and I am interested in adapting it so that I can use it with vector Fields where that include RootOf expressions.

The above includes an example where it works, and an example where RootOf appears in the vector field and it does not work. 


I have been making a 3d graph of the level sets of a function. Here is the code for the 3d graph:

display(seq(seq(plot3d([i/sin(u), u, j], u = 0 .. 3/2, t = 0 .. 10, view = [0 .. 10, 0 .. Pi/2, 0 .. 10], color = i*j), i = 1 .. 10), j = 1 .. 10))

Each curve is a different level set- and I'd liketo colour them all individually -so people can tell tham appart. Any variation of the code I've made makes each of the curves black.



I am new to parallel computing, but as my current desktop is struggling with caclulating Groebner bases (i've been locked out for most of a week), I've contacted my universities center for scientific computing in the hope that they could do the caclulations.

However, I've been told that maple doesn't run in a distributed-memory parallel sense; as parallelisation in maple is very new - and i couldn't find discussion of this in the documentation - I thought it would be best to ask here if it does.

Secondarily can commands from the GB package be implemented in a way that would benefit?
if not can other similar commands like solve or eliminate?


I am woking on a pharmo model for a freind, and it includes a variable called depot that needs to jump up by 150 every 24 hours.
currently I have written it as:

diff(Depot(t), t) = piecewise(t = 0, -Ka*Depot(t)+150, t = 24, -Ka*Depot(t)+150, -Ka*Depot(t))

clearly thats wrong though, as the +150 s don't make it jump up by 150 because of the small step size.

(at t=0, it adds 150*a small step size, at 24 it looks like it adds 150* a vastly smaller step size, what I want would be much closer to a series of pulses each decaying to almost 0 and then getting boosted to just over 150)

My intuition is that i need to use the dirac delta function but in such a way that its integral adds 150 instantaneoulsy every 24 hours. I have no idea how to do that!

I've just realised that this ode has an obvious solution, so you can trivially make a function that adds 150 every 24 hours and exponentially decays in between.  However there are other models that hopefully i'll being doing similar work on, that don't have nice solutions]


Hi i was trying to numerically integrate my freinds model with dsolve, and i am sure that I have put all the right components in the command as described in the help page, but it doesn't work. (Here is a worksheet with the model )

What is the problem with the way I have called the function?
Does anyone have a mental checklist that they use for dsolve commands? because I often struggle with making them work.


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