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bio website verbeia.com/mathematica/tips/…
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visits member for 2 years, 2 months
seen 4 hours ago

Jul
21
comment Logarithmic slider
Amazing that you went so deep into undocumented functions!
Jul
13
comment Help in NIntegration Methods - Takes too long, why?
You might be able to answer your problem if you study the page here.
May
18
comment How to create internally optimized expression for computing with high WorkingPrecision?
performing arithmetic operations in the right way can reduce round off errors. One important example is use of HornerForm (a built in function) for computing polynomials. Most text books on numerical methods show a few other tricks for specific cases. It's all about avoiding catastrophic cancelation, which is the loss of precision due to subtracting numbers that are nearly equal but not close to zero.
May
18
comment How to create internally optimized expression for computing with high WorkingPrecision?
It might work better if you make jacobianMatrix a CompiledFunction. That will help if FindMinimum uses MachinePrecision to get close to the optimal solution, and switch to higher precision for fine tuning.
Jan
31
comment What are the use cases for different scoping constructs?
Yet another scoping construct that I didn't see mentioned is DynamicModule.
Jan
12
comment Interactive steam tables and phase diagrams in Mathematica
For years I have wondered why Wolfram hasn't included each steam table as an InterpolatingFunction.
Oct
28
comment A good way to manage code in a complicated CDF?
I saw SaveDefinitions before, but couldn't remember what it's called. I think that's the solution to my problem. Although I haven't had a chance to try it. I would accept it as an answer if you entered your comment as an answer.
Aug
28
comment Creating a Tooltip that knows what platform is currently being used
This is the best criteria to use. However, failure to use Dynamic (See RM's solution) is real cause of my problem.
Aug
19
comment Compiled version of (Norm/@coordinates)
Silly me, I checked the list of compileable functions and didn't see it. I also didn't know about Internal`Square.
Aug
14
comment How to switch between different CDFs in CDF Player?
@ Mark McClure See my edit above
Jul
29
comment What is the difference between Set and SetDelayed?
I discuss that in great detail here.
Jun
18
comment The difference between 0. and 0
We also have 0.0*I which is a complex number that is approximately zero. Also have 0.0''200 which is a real number known to have absolute value less than 10^-200. I find it inconsistent that Head[Re[0.0 I]] is Real, but Head[Re[1.0''200 I ]] is Integer.
Jun
12
comment Can't get DynamicModule[{..},..EventHandler[] ] working
Sorry for being a pain, but I still haven't learned how to format the code. Much of the time I come here using my iPhone which has many features in stack exchange missing. Sometime when I am at home, I will try to contact one of you on chat and learn some stuff. Want my email address?
Jun
12
comment When to make (file.nb) instead of (file.cdf)?
there is more to it than that. WRI could have made it so you can't use the Option Inspector to modify a CDF file. They could have made it so you can't use Drawing Tools in a CDF file. It turns out you can use Mathematica to do these things, but you can't know that from looking at the file with a text editor. I found out that I can do those things because I tried and they worked. The problem is that there are a few hundred other features that may or may not work.
May
13
comment Does Mathematica have advanced indexing?
I like the UnitStep, ReplacePart solutions a lot. Some of the other solutions are very complicated and sure to turn off people who are new to Mathematica. .... I think I finally figured out how and when to 'Add Comment' in this forum :)
Apr
13
comment How does Interpolation really work?
I understand cubic spline interpolation has a few different varieties depending what the derivative does at the end points. I thought InterpolationOrder->3 used a cubic spline interpolation. Is a cubic spline interpolation a specific case of a B-Spline?
Apr
6
comment Expression evaluation inside of FindRoot inside a Compiled Function
In that case you still might be able to improve performance if your compiled code includes a root-finding method built from scratch. It looks like you are doing root finding in 1D. If you know you can start with two points where the function changes sign Brent's method is a great choice. I could provide a Mma implementation of Brent's method. If you can't use Brent's method, another method such as Newton's method or secant method might work well. They are both easy to implement. You may also need to roll your own version of other function that can't be compiled.
Mar
19
comment Quality of random numbers
To learn about issues with the legacy Random numbers check MathGroup. Search for "Andrzej Kozlowski Random" and I think you will see those issues explained and discussed.
Feb
22
comment Are there any cases when For[] loops are reasonable?
In my RootSearch package I call an iterative algorithm which looks for a root where there is likely to be a root. That algorithm calls a function which calls a function and so on. A few functions deep it may be discovered that the function whose roots we a looking fo is not defined at the new approximation of the root. When that happens I use Throw to give up on the iterative algorithm in that neighborhood. I don't know if you call that an exception. Also, we can use Check to take certain action when we compute 0/0 etc.
Feb
22
comment Root finding in Mathematica
Maybe Roots is what he is looking for. He might also want to use ToRules on the result Roots returns.