xzczd
Reputation
5,931
Next privilege 10,000 Rep.
Access moderator tools
 Mar28 reviewed Close Integrated Solution Graphics Mar28 comment 4th-order Runge-Kutta method to solve a system of coupled ODEs Just copy and paste (Ctrl+C and Ctrl+V under Windows), as you copy and paste any thing. BTW, if you add a white space before "@" and "xzczd", the reminder won't work. It should be "@xzczd". Mar28 comment 4th-order Runge-Kutta method to solve a system of coupled ODEs Select your code and press Ctrl+Shift+I before copying. And you can also use this to convert your code to make it look better. Mar26 revised How to modify a PDE inside NDSolve according to an if condition deleted 10 characters in body Mar26 answered How to modify a PDE inside NDSolve according to an if condition Mar26 comment How to modify a PDE inside NDSolve according to an if condition Well, I still suggest you to add the missing b.c.s, though NDSolve gives an answer currently, it's not that clear what boundary is added. Mar26 comment Delete duplicates by a criteria And your syntax for DeleteDuplicates is even incorrect. Mar26 comment How to modify a PDE inside NDSolve according to an if condition Is the function f[t, y, x] or f[t, x] or f[y, x]? And you still miss 2 boundary conditions. (A rule of thumb for the necessary number of i.c. or b.c. is that it should be usually equal to the highest order of the corresponding derivative.) Mar26 comment Complete definition of special functions in Mathematica I prefer pressing F1. Mar25 awarded Popular Question Mar23 comment How to accelerate my code? @Purboo "I think I need to learn Compile first." - Before that, I suggest you to read the last paragraph of this answer. "Sometimes it is not easy to write code using functions like Apply, Map and Thread. " - Yeah, sometimes, but quite rare in my opinion, in most cases, it's just because you're not familiar enough with the coding style of Mathematica. Mar22 comment Coupled non-linear differential equations @Ricoleto As mentioned above, it's just a result of trial and error. Sadly it seems not to be able to handle Tmax=10, and I haven't think out a corresponding solution yet. I think it might help if you add some background information about your equations to your question. BTW, I just noticed that the b.c. in your code is different from what you claimed in the text i.e. $m(0,t)=m(\pi L,t)=v(0,t)=v(\pi L,t)$, is it intended? Mar21 reviewed Approve Square both sides of an equation? Mar21 revised How to propel the integration of time a little bit further? Numerical solution can not evolve to the max time added 134 characters in body Mar21 revised How to propel the integration of time a little bit further? Numerical solution can not evolve to the max time added 134 characters in body Mar21 answered How to propel the integration of time a little bit further? Numerical solution can not evolve to the max time Mar21 revised Coupled non-linear differential equations deleted 2 characters in body Mar21 comment Coupled non-linear differential equations Seems that this hasn't been done yet: Hello, welcome to Mathematica.SE! I suggest the following: 1) As you receive help, try to give it too, by answering questions in your area of expertise. 2) Read the faq! 3) When you see good questions and answers, vote them up by clicking the gray triangles, because the credibility of the system is based on the reputation gained by users sharing their knowledge. Also, please remember to accept the answer, if any, that solves your problem, by clicking the checkmark sign! Mar21 comment I have several functions and how I know which one is the maximum in a certain range? Please post your code instead of the picture so we can test it easily. Mar21 revised Coupled non-linear differential equations a new observation added.