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Mar 6 |
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Collecting roots of different equations and create a list You can use Select or Cases to filter out real roots. Please see update |
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Mar 6 |
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Collecting roots of different equations and create a list Yes, sure. please see update |
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Mar 6 |
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Copy and pasted graphics are fuzzy may be you can make the example code more complete by adding the line that generated the residualsdata |
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Mar 6 |
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2D Heat equation: inconsistent boundary and initial conditions the IC and BC look to be consistent. But something to look at, your I.C. lead to $k\left( \frac{\partial^{2}u}{\partial x^{2}}+\frac{\partial^{2}u}{\partial y^{2}}\right) =-5k\pi^{2}\cos\left( \pi x\right) \sin\left( 2\pi y\right) $. Hence from the pde itself, this means at $t=0,\frac{\partial u}{\partial t}=-5k\pi^{2}\cos\left( \pi x\right) \sin\left( 2\pi y\right)$ Now see if this is consistent with the B.C.'s shown. I could not find conflict. But it could be becuase you have neumann boundary conditions at the 2 other sides, it could not verify the consistency there, that is all. |
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Mar 5 |
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How is the Mathematica kernel structured internally, and how does evaluation work? You are mixing things. Java is open source. The source code is there to see and for any one to read. The internals of the JVM itself is all there to see. There is a whole book on Java VM. Mathematica is closed source. So all what you can learn about its internals, is whatever we are allowed to see through the glass windows, that is all. Also see Why You Do Not Usually Need to Know about Internals reference.wolfram.com/mathematica/tutorial/… |
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Mar 5 |
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Evaluate Numerator and Denominator Separately +1 good answer. Better than user having to use Hold in the call. Will delete my answer. Yours is much better. |
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Mar 5 |
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Evaluate Numerator and Denominator Separately The ComplexInfinity is coming from M evaluating 1/x to ComplexInfinity BEFORE it even reaches your function. When you write foo[1/0] then M simplifies 1/0 to ComplexInfinity right away. |
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Mar 4 |
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How is the Mathematica kernel structured internally, and how does evaluation work? @belisarius True. But it describes the main kernel loop. Which I assume remain the same all these years? I would not know ofcourse, only someone who works inside WRI would know for sure. Just thought it was interesting read. I know I enjoyed reading it (even though a lot of it was over my head ;) |
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Mar 4 |
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How is the Mathematica kernel structured internally, and how does evaluation work? see "Mathematica Internals: A Tutorial " by Daivd Withoff library.wolfram.com/infocenter/Demos/4683 |
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Mar 4 |
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Vertical “fractions” with more than 2 parts It will help to say, what is it you are trying to actually accomplish. What is the purpose of this? Just for formatting expressions on the screen? |
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Mar 3 |
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Construct a sum that evaluates its arguments but doesn't evaluate further .. !Mathematica graphics notice the use of Sum and not sum and also it took the variable body. I wish M has something like these. I think Inert functions in Maple are much easier to use than Mathematica Defer Hold and its family of functions. I always get confused by which of those Hold functions to use and when and where to use them. |
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Mar 3 |
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Construct a sum that evaluates its arguments but doesn't evaluate further Nice. But this has limitations I found. For example, if I write the body as separate variable outside, then use that variable body inside the sum, it will not evaluate body . Here is screen shot of what I mean: !Mathematica graphics So it forces one to put everything in that expression. Maple actually does all this sort of thing a little better than M. Maple has what is called Inert functions. There are Sum and sum. The Sum is for display. Then one calls value to evaluate it. Here is an example of same problem in Maple.... |
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Mar 3 |
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Variable substitution in sum's index It seems the Sum will either evaluates to something and if not, then it remain as is. i.e if M can't evaluate it, then it will leave it as is. It will not look inside it to see it it can simplify the internal for specific index. No point. The sum does not evaluate. Since Sum[1/Sqrt[n!], {n, 1, Infinity]}] does not evaluate. I tried this on Maple and Maxima, and they both do the same as M. So, this will require special function to handle this specific case. |
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Mar 3 |
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The built-in function If behaves strangely in a procedure/function I could not follow your code. But you say ` program to generate sequences of "1", "2" and "3" with no equal consecutive pairs.` Is this sort of what you mean? lst = {1, 2, 3}; Permutations[#] & /@ Subsets[lst] This gives !Mathematica graphics if this is not what you want, then may be give small example of input/output needed. (ps. not good idea to use procedural coding in M, no goto, etc...) |
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Mar 3 |
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The built-in function If behaves strangely in a procedure/function example? If should behave the same way inside a Module or outside. If you find that If does not do so, this would qualify as a huge bug and should be submitted to supprt@wolfram.com for more investigation. But again, you should provide an example of what you mean as this could be a user error. |
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Mar 2 |
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How to write a differential operator in Mathematica @acl, I changed the order. I assumed you meant it should be Function[f,x] vs, Function[x,f] just to make it look better. @jens, sorry I am not following your suggestion. First I would never use global thing. I hate global variables, anything global, I will never ever use global variables, ever ever will do that. As for your second suggestion to use the first slot in f, but the argument to f is used inside the cos and sin functions as well? Why make it complicated? Why not simply pass the function and its argument separate? May be I am missing what you mean, an example will help? |
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Mar 2 |
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How can I change the color of the bar in a ProgressIndicator? I do not think this is possible. This control uses platform native widget, color is whatever the OS decides on it. |
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Feb 24 |
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How to dynamically toggle curves on/off in a crowded Plot? You say The buttonbar above the plot is not a natural interface. Clicking on the curve or legend would be a natural action to toggle a curve's visibility. But in this case, what would the user click on to toggled it back? Hence one needs a button there all the time, like you show above yourself. If one toggles the legend to remove the curve, then there is no where to click any more to bring it back. I see nothing wrong with the way you have it above. It seems very natural. |
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Feb 24 |
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Distance between point and line segments @MikeZ. Thanks. I forgot the Abs on the distance from the formula in the reference. I will add that now. As for the perpendicular dashed lines, I added that myself. It depends on which side to take the angle with. So I need to look at this more to make it more robust. So, for now, will remove the dashed lines as I do not have time to look at it. But the distances is correct. |
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Feb 24 |
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Include a CDF file in sites.google did you try this wordpress.org/extend/plugins/wolfram-cdf-plugin |
