TomM

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17 years, 17 days

Professor of Economics SUNY Stony Brook I use Maple for Research: To test theoretical modelling ideas with various kinds of general equilibrium deterministic and stochastic models in Macroeconomics and Urban Economics. Graduate classes: In Macroeconomics and Econometric classes. Undergraduate classes: In Urban Economics and Computational Methods classes. Note: You can communicate with me in German and French as well as English.

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These are questions asked by TomM

When I create a component, here a label component, and set a name property and then click OK, that name seems to go into some list never to be erased. If I then delete the first name and put in a new name and click OK. thus saving it, and the then try to use that name again on a different component, I am told that the name is already in use. Well, no existing component has the name, but it is still in Maple's list of components. If I go to edit an action for any component and input %+command completion, I get a list of components which includes the deleted name which does not belong to any existing component. Since the name is on this list, I cannot reuse the component name.

How do I clean up this erroneous list of component names, so that a mistake in naming one component doesn't forever prevent me from using it on the component for which it was intended?

 

I have a Text Region (made with T tool) which does contain some math elements. However, as I understand it, such a region should not be executable. When execution is attempted (by using ! with the cursor in the region), the cursor should sinply jump to the next group (executable or not). Instead, I get the following output error line as though it were an execution group and the cursor remains in the region.

Error, "=" unexpected

How is this possible?  Is there s code hidden behind the visible text that causes this?

This happens even after I copy the whole text in the region to a text region in another worklsheet.

The toggle button in the embedded components has a default image which points up and down. Is there any way to rotate this image so that it points left and right?  I though I might actually just rotate the default image gif(?) directly, but the properties window does not give the location of the gif(?) used for this image. I also can't locate the image file simply looking at the Maple program folder. Otherwise, I have to go find or create an image of my own.

When Matrix or Vector output that has variables with assumptions on them (and therefore with tildes on them) is copied and pasted to the expression argument of a map( ) function, the map code cannot find the assumptions. Of course, when it is pasted in appears in the input with the tildes.  It then seems to not recognize the tildes as indicating assumptions on the base name.

If, on the other hand, the output is directly saved to a name, and that name is used in the input to the map( ) function, then the assumptions are recognized and the output is correct. It seems that in this case, the tilde is an output phenomenon that is not recognized on input. Apparently, the save output is not saved with the tilde.

Here is a simple example:

> assume(a>0, b<0);
   v:=<a,b>;

   see_assump:=proc(x)
     print(getassumptions(x));
     x;
   end proc:

map(see_assump, v);

map(see_assump, <a~, b~>;
map(see_assump, <copied from output of v assignment statement above>);

The first map statement shows the assumptions, the second two just give empty brackets { }.

Attempting to use more complicated procs that require the assumptions in the map( ) function leads to incorrect answers or failure to evaluate in the last two cases.

With Maplets, it is possible to create popup windows to tell or ask the user something, but only when it is appropriate. That is, it is not there all the time. A particular usage would be to give the user a facilitating question when they have incorrect entries.

Is that possible in some way with Möbius apps also? Or does one have to always keep a blank TextArea available, just a blank space if invisible perhaps but using up space in the presentation nonetheless, to give the student the information?

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