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41653
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location Ann Arbor, MI
age 76
visits member for 1 year, 6 months
seen 1 hour ago

I am a retired software developer. I retired at the end of 2003 and since then my computer programming activities have been for recreational purposes. I find Mathematica excellent for that.

I started using Mathematica in 1997 (Ver. 3). I am currently using Ver. 9. Although I have used Mathematica for all kinds of stuff, I use it mostly to pursue my long standing interest in Euclidean geometry, both in the classical Greek synthetic form and in the more modern analytical form.


3h
comment How to get integer/rational and real eigenvectors to be the same?
possible duplicate of Eigenvector Anomaly
1d
comment Aligning controls and their labels to grid?
Add an empty string in position {1,3) of your slider declarations. For example, Control[{{speed, 1}, 1, 30}] becomes Control[{{speed, 1, ""}, 1, 30}]. Then no variable name will show up on the left of the slider.
1d
comment Splitting a list into list of lists
What you want is Partition
1d
comment draw graphics in cycle
This question appears to be off-topic because it is too localized; i.e, it applies only to the local situation and needs of its poster and answers will not benefit others.
1d
comment Shift text upwards in graphics so characters with descenders clear horizontal lines
@Mr.Wizard. Edited answer to add code. It was posted in the chat room where we discussed this question. Sorry I didn't think to show it.
2d
comment Shift text upwards in graphics so characters with descenders clear horizontal lines
Click on the stack exchange logo on the site toolbar. On the drop down menu, click on "chat"
2d
comment Shift text upwards in graphics so characters with descenders clear horizontal lines
Your sample code doesn't reproduce your problem on my system. Both h and g are aligned to same baseline, with the descender of the g going below the line. Might be good to discuss this in chat. I'll open a chat room.
2d
comment Shift text upwards in graphics so characters with descenders clear horizontal lines
How do you want it adjusted? And with respect to what? Also, I think you need to post more code. Context is important here. An example pruned down to two or three time lines will do.
2d
comment How to solve Stokes equations with non-vanishing boundary condition on two spheres?
I think you get help with the formulation of your problem form Mathematics.SE first and then come back here for help on implementation after the formulation is solid.
2d
comment Open a pre-existing CDF file from a stand-alone CDF file
As I understand it, CDF documents that are written to run in the free CDF player cannot access the file system of the computer they are running on. This is a matter of system security.
2d
comment How do I constrain movement for lists of Locators using 2nd argument of Dynamic?
To clarify the point of my previous comment, the reported behavior is not a property peculiar to locators, but applies to any dynamic graphic.
2d
comment How do I constrain movement for lists of Locators using 2nd argument of Dynamic?
The behavior you describe is general to expressions displayed dynamically. For example, if you create a 3D graphics object, evaluate it, rotate the object in the output image with the mouse, and delete the output, when you re-evaluate the 3D graphic, the new output image appears in the rotated position of the deleted image.
Apr
15
comment Need to create a function to generate all permutations of Range[$n$]
14! is a rather large number, so I understand why you might not want to store all the permutations in memory. However, even if you accomplish your goal of generating the permutations one-by-one, how long do you think it will take to score more than 87 billion lists of 14 integers?
Apr
14
comment Counting the number of instances of one sub-string within a given string within a lower- and upper-bound gap of a second sub-string
OK, I think it's clear enough now that @LeonidShifrin can solve it for us :)
Apr
14
comment Counting the number of instances of one sub-string within a given string within a lower- and upper-bound gap of a second sub-string
As I see it now, string2 is the target, the item of interest, while string1 is a landmark that only serves to define the gap. Is this correct?
Apr
14
comment Counting the number of instances of one sub-string within a given string within a lower- and upper-bound gap of a second sub-string
So string2 is special in the sense that if the values of string1 and string2 are exchanged, the resulting value of the count may be different?
Apr
14
comment Counting the number of instances of one sub-string within a given string within a lower- and upper-bound gap of a second sub-string
The problem may be clear in your mind, but I find it completely confusing. What has string1 and string2 to do with your example code? How does bigString come into play? You never mention it your text description of the problem.
Apr
14
comment How to change the appearance of a group opener?
@Sylvia. On OS X a group opener is a right facing triangle. I think it is stored in /Applications/Mathematica.app/Contents/Resources/RightArrow.icns, and I think one would have to change that icon file to change the appearance of a group opener. However, I am too timid to try the experiment on my system, so I don't know for sure.
Apr
14
comment DSolve failing to solve second-order ODE with two boundary conditons
One possibility is that somewhere in your earlier session x was assigned a value, so your equation was no longer the symbolic expression you thought it was.
Apr
14
comment DSolve failing to solve second-order ODE with two boundary conditons
The easiest way -- if you are new to Mathematica -- is to save your notebook and restart Mathematica and reload the notebook. Or -- if you are feeling more adventurous, you can select Quit Kernel > Local from the Evaluation menu.