I have succeeded in generating a nice plot of a surface in which I am interested, and have calculated geodesics on the surface. Is it possible to display one (or more) geodesic curves on a 3D plot of the surface? If so, would someone point me in the right direction to do so. I've looked at "multiple", but don't see how it's applicable to my problem.
Don Ritchie

I am trying to animate a sphere/ so that it kinda looks like the globe rotating.
This is what I have so far. Also if any body knows how to tilt a sphere so that it is on an angle. that would greatly help.
with(plots):with(plottools):
globe:=sphere([2.0, 1.5, 1.5], 1):
display(globe,scaling=constrained,style=patch,axes=normal):

Here's a substitution that briefly surprised me. It makes sense once you understand what is going on.

subs(true = false, proc() local i; for i to 3 do true; end do end proc);
proc() end proc

We have a maple 10 site license and I recently started to use maple for some challenging symbolic manipulation. Specifically I wanted to find the 3-dimensional eigenvectors A(u,w) and eigenvalues \lambda for a system of 8 partial differential equations. I was disappointed when maple completed most of the problem finding all 8 eigenvalues but only 6 of the 8 eigenvectors. In fact explicitly issuing Eigenvectors(A) command didn't seem to work as it ran for a long time with out returning so I ended up just issuing a series of LinearSolve(A-\lambda I|0) commands. This worked for the first 6 eigenvalues but for the last pair of eigenvalues maple just didn't do anything simply printing the command I issued. Maple didn't print any diagnostic information to let me know what went wrong. My question is when Maple doesn't evaluate a command how does one obtain information about what went wrong?

Hello to evereybody!!
I'm newbie with Maple and I've to do a program that calculates the rank of a Matrix, I can't use the comand rank or similar.
I think it's something like:
repeat
If det(A) =/= 0 then rang := nº rows
else
reduce(a)
until rows=1 or det(a) =/= 0
But i don't know how to codificate it in maple!!
Help!!!
Thanks for reading my problem...
Sorry...If my english is bad i'm not from England or Usa

I was wondering if one could animate a tubeplot. if so i am trying to animate this tubeplot that i created so it can look like a tornado in action.
tubeplot([20*t*cos(t+7),20*t*sin(t+7),20*t],t=0..20*Pi,
radius=-100*exp(.00001*t), tubepoints=20,
numpoints=100, color=grey);
and if you can't does anybody know how I can animate a space curve similar to this to make it look like a tornado.

In this case there is a singularity at t=0, but the command singular() does not give it:
singular(1/cos(1/t));
{t = 2/(Pi*(1+2*_Z1))}
With the numeric range option it gives the correct answer:
singular(1/cos(1/t), -1 .. 1);
{t = 0}, {t = -2/(39*Pi)}, {t = -2/(37*Pi)}, {t = -2/(35*Pi)} etc.
The command discont also gives the correct answer:
discont(1/cos(1/t),t);
{0, 2/(Pi*(1+2*_Z2))}
I have maple 11.

I am trying to recreate a transcendental equation from a paper on buckling analysis. I have not been able to successfully manipulate equation (10) given on page 692 of the attached files into the final forms of equations (12) and (13), using the boundary conditions given in (11). Could someone take a look at my Maple worksheet and offer some suggestions that would yield an elliptic integral?

Download 4865_Lo_p692.pdfView file details
Download 4865_Lo_p693.pdfView file details
Say I have a directory of files with names:
sim01.m,
sim02.m
...
sim20.m
I can automate the collection of the names of the files with
>file_list:=FileTools[ListDirectory]("D:\\MapleVariables\\Data"):
but how do I automate the reading of the files ie how do I append each file name in file_list to the end of the command:
>read "D:\\MapleVariables\\Data
so I can then read it

Using Maple 10.05 with Windows XP Pro, how do I write a Maple command containing the _ character, without having it make a subscript?
Specifically, there are some defined procedures whose names contain the _, such as geodesic_eqns(.....) in the tensor package. I've tried all kinds of key combinations, without success, to get that _ not to act as a subscript designator.
Don Ritchie

HI all,
I have the following formula in Maple:
Assume(eps>0, v>0, k>=0, n> 0, k, 'integer', n, 'integer', k

I have searched and googled all over places, just couldn't figure out how to save all the variables in the current workspace.
save all, "myfilename.m"
doesn't work at all.
There is no such usage in the documentation.
When you have many variables, how do you save them all?
-----------------
Two quick side questions(without opening a new thread):
Q1:
If you have two statements joined together, how to separate them?
I am using GUI in Maple 11:
Example:
statement_x; statement_y;
how to break them into:
statement_x;
statement_y;
Every time I hit "Enter" after statement_x, both got executed. After long waiting(they happened to be both huge and messy), messy results were printed out, I have to scroll many pages, but these two statements were still together. Annoying!

Codegen: floating point constants vs. symbolic constants
Let's say in a complex-valued function, constants such as 1/2, 1/4, etc. are involved. I found, upon some experts' advice, the symbolic computations are different. If one expression is too hard to evaluate or simplify, changing the constants back and forth between floating point constants 0.5, 0.25, etc. and symbolic constants 1/2, 1/4 or one way or the other will often help.
However, our end goal is code generation and translation into C or Fortran. Will the efficiency and accuracy be different in the translated end results for the floating point constants and symbolic constants cases? I roughly found no difference.

Gradient: thought comparison of the codegen version and the symbolic version.
This is something I don't understand. There are two ways of obtaining the gradient of a function: (1) codegen uses auto-differentiation; (2) derive the partial derivative symbolically. Both can be translated into C or Fortran code, since my end goal is the C or Fortran code.
The documentation claims the auto-differentiation is more efficient. I don't understand. Any more complete views about this matter? Does auto-differentiation win both in accuracy and efficiency? Or perhaps there is a trade-off between efficiency and accuracy? I just wanted to hear more opinions from your experience. Thanks a lot!

I recently switched from XP to an Intel Mac (OS X 10.4.9); I am using Maple 9.5 on the Mac. In contrast to Win XP the backspace key does'nt work as expected (delete the previous character). Is there any other key or combination of keys for deleting characters?
Regards
Wilhelm