Tim Vrablik

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12 years, 314 days

I work in Maplesoft’s Applications group. This group is a hub between Sales/Marketing and R&D. I primarily work with customers to help them use our software for their projects.

Born and raised in Windsor, Ontario, I spent a substantial chunk of my life there. I attended the University of Windsor to study Engineering and Math, and moved to Waterloo to start working with Maplesoft.

My first introduction to Maple was in a differential equations class. Our professor swore by it every day, and felt obliged to show us examples on how to use it at the end of every class. Admittedly, I usually skipped out of class right around that point. It wasn’t until I sat down and used the software to do my homework that I truly realized how useful Maple was…I only wish I had heeded my professor’s advice in the first month of the semester instead of the last.

MaplePrimes Activity


These are answers submitted by Tim Vrablik

Would the cross section plot help?

You might want to load the ?units package (some simplifications are done automatically for you).

For your first question: you can use the new point probe tool ?worksheet/plotinterface/pointprobe to trace your plots and retrieve coordinates.

For your second question, I'm not sure if this is what you are looking for or not.

 

Hope this helps.

Here is another example using the variable t directly in the rigid body frame component instead of using the real expression.

try3.msim

 

TV

With the current release of MapleSim, we do not have the required port types available in the custom component template. This is a feature that will be available in a future release.

 

TV

You can use [ctrl]+[shift]+[quote] to get the cursor over the character (in Windows). Use periods for the dot notation, then hit the right arrow to return to the base line. Not sure, but you may find this worksheet useful too: www.maplesoft.com/applications/view.aspx?SID=6588

 

Hope this helps.

I've come back to edit my post. I originally thought that we could only handle scalars, but after playing around with an example a bit more, it seems that isn't true. I think what might be the issue here is the units. You can create a parameter that is a matrix for say a rotation matrix (has no units). You can also create row vectors as parameters and it doesn't matter if it has units or not. There seems to be a problem with the matrix having units associated with it (in this case kg*m^2). As a work around (although not ideal), you should be able to assign parameters for each of your elements in the matrix.

I had tried re typing both of your assignments for X & Y and they seemed to be alright.

X := Vector([0, 1.01, 2.01, 3.01, 4.02, 5.02, 6.03, 7.03, 8.03, 9.04, 1.11, 1.21], datatype = float[8])

> Y := Vector([-4.77-11, 0.133e-8, 0.275e-8, 0.423e-8, 0.579e-8, 0.724e-8, 0.860e-8, 0.102e-7, 0.117e-7, 0.132e-7, 0.148e-7, 0.165e-7], datatype = float[8]);

I entered them both in the default Document mode.

1. You can use subscripts. Note that there are two different types literal and index/rtable. To use a literal subscript, which is what it sounds like you want, use [ctrl]+[shfit]+[-] and not [shfit]+ [-]. As an example to see the differences, try typing in this:

restart

i:=2

x [shfit]+ [-] i (this will come up as x_2)

y [ctrl] + [shfit] + [-] i (this will come us as y_i)

 

2. For greek letters, type in the name of the letter and press [ctrl]+[space] or [esc]+[space] and a keyboard shortcut menu should pop up. Select the letter from the options and it will be dropped in (it may also happen automatically if there are no other Maple commands that are close to the letter you are typing in).

The key idea is that the choice of modelling coordinates (i.e. the variables that will appear in your mathematical equations that describe the system) directly influences both the number and complexity of the resulting equations.
For instance, a single pendulum can be modelled with a single coordinate, theta (representing the revolute joint angle), resulting in a single dynamic equation (ODE).
Alternatively, it could be modelled with absolute coordinates (xyz translation of the pendulum mass as well as 3 angles representing the mass’s orientation in 3Space).  In this case you obtain 6 ODEs (one for each coordinate) as well as 5 kinematic constraint equations, accounting for the fact that the 6 variables are not independent of one another.

These are all determined by initial conditions. If you set your IC to ignore, then IC's aren't taken into account and the simplest form of equations are generated to simulate your model. If you set it to treat as guess, then it will try to use your IC's, and if you set it to strictly enforce, your IC's are used and odds are that your coordinate system will change.

Hope this helps.

If you include the option symbolic, it will simplify as you expected.

Each version of Maple will install in its own folder, so this won't be a problem.

Try looking at ?plot and ?plot,details. This should get you what you need.

Is this what you're asking for? If so, you can use ?Eigenvectors to get you started.

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