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Nov
20
comment Why does LyapunovSolve solve non-standard form?
Ican't tell now, but just to note that Matlab also solves the same form as Mathematica: mathworks.com/help/control/ref/lyap.html.
Nov
19
comment Why does LyapunovSolve solve non-standard form?
whereas the standard form of the Lyapunov function When one says the standard is this and that, it will nice to show a link?
Nov
19
comment Better Autocompelete for the Front-End
Since version 9, autocomplete behaves the way it does in modern IDEs except for one big shortcoming how-to-keep-the-ctrlshiftk-help-menu-remain-in-display-while-typing (and there is no answer to this as of version 10.01)
Nov
19
comment How does Mathematica integrate?
For example it fails on Integrate[x^3 ExpIntegralE[1, x], x] as of version 10.01, M can now solve this and gives this: -x^3 ExpIntegralE[2, x] - 3 (x^2 ExpIntegralE[3, x] + 2 (x ExpIntegralE[4, x] + ExpIntegralE[5, x])) which is the same as the expression you show. (after some simplifications)
Nov
18
comment Catastrophic loss of precision
Please change the letter l to something else, say L0. I can figure if I am looking at a 1 or l in your code, they look very much the same.
Nov
17
comment How to extract a list of available Method-s
@AlexeiBoulbitch I've added another function to filter only those options which has the Method-> on them and only show those. I kept the original function as is.
Nov
16
comment For loops in Mathematica
n = 5; For[i = 1, i <= n, i++, For[j = 1, j <= n, j++, If[i != j , Print["i=", i, " j=", j] ] ] ] screen shot to confirm the result !Mathematica graphics
Nov
16
comment Troubles with FindFit for ODE
This code (from documentation) works The code does not work. screen shot: !Mathematica graphics you might be missing some additional code. Please post complete working code.
Nov
16
comment “Independent” Variables in Manipulate
if you make your code readable, may be you'll get better help. I can't even read the code. This is how it looks on my notebook !Mathematica graphics may be it will help if you start by removing all the subscript boxes stuff.
Nov
14
comment Creating an orrery
most folks here use Mathematica, and systemModeler is separate program from Mathematica. I suggest asking at community.wolfram.com they have special group for system modeler there.
Nov
14
comment How to indroduce a value for the functions inside a matrix?
@Mike it works ok for me. Make sure to restart the kernel before to clear things. screen shot !Mathematica graphics since you are using D in there, you can't now use numbers for x,y, they have to remain symbols.
Nov
14
comment How to indroduce a value for the functions inside a matrix?
@Mike please post source code in the question itself (append at bottom, leaving original unchanged). Hard to debug from screen shots
Nov
14
comment How to indroduce a value for the functions inside a matrix?
@Mike if what you mean is that you are having a new problem and unable to figure it out, then you can post a new question and someone will try to help.
Nov
14
comment Calculating integral by Romberg Algorithm
@ShutaoTang one hr? No, it runs in Matlab just as fast as with Mathematica. I can't imagine why this would take one hr. May be your friend has a bug in the code. They can run the Matlab profiler on it to find where the slow down is.
Nov
14
comment Calculating integral by Romberg Algorithm
@belisarius it is not functional because the original HW here and here was in Matlab actually, and I just did now a quick 1:1 translation on the fly. (did not want to change many things so not to break it :)
Nov
14
comment How to indroduce a value for the functions inside a matrix?
btw, your e1Psi1 and e1Psi2 and e1Psi3 are not functions. There is no pattern in the lhs, and function normally defined with := and not =. All what you have there is just normal expression assignments.
Nov
14
comment How to indroduce a value for the functions inside a matrix?
I am not following your question very well. If you want to assign values to the x,y, inside psi, just so psi/.{x->1,y->2} should do it.
Nov
14
comment Calculating integral by Romberg Algorithm
what does HW assignmentmean it means it was a home work, for school. I took a class and this was one HW.
Nov
14
comment Calculating integral by Romberg Algorithm
I understand what this is doing. My point is that, you should first work on the algorithm to make sure it works, but eliminating any un-needed extra fancy complexity. You can always fine tune things later if needed. I'll try to look up my HW and post my code.
Nov
14
comment Calculating integral by Romberg Algorithm
I do not understand why you are dealing with Precision stuff in the implementation of this algorithm. I've implemented this also for a HW assignment but do not have time to post it now. I think you are making things much more complicated than needed with adding Precision in there.