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 Feb 20 answered Puzzle with Mathematica Feb 20 comment Implementation of a matrix formula @J.M. Oh, you're right, row.Transpose[pts, {1, 3, 2}].col can be further simplified to col.(row.pts) in this case, the speed improvement is negligible though. (Transpose is so fast. ) Feb 20 comment Why is ListPlot[] so slow for coordinate pairs? Can we speed it up? @AlbertRetey Your guess is right, at least according to the AbsoluteTime[]-t measurement, but this leads to another problem, that is, the AbsoluteTime[]-t measurement seems to be inaccurate, too, if my sense of time is correct! (Maybe I should pinch a stopwatch?) Feb 19 awarded Popular Question Feb 18 revised Why is ListPlot[] so slow for coordinate pairs? Can we speed it up? added 1 character in body Feb 18 comment Why is ListPlot[] so slow for coordinate pairs? Can we speed it up? @Kuba Yeah, I noticed it just now, too. Quite surprising I should say, I thought ListPlot is just a Graphics generator! Feb 18 revised Why is ListPlot[] so slow for coordinate pairs? Can we speed it up? added 216 characters in body Feb 18 revised Why is ListPlot[] so slow for coordinate pairs? Can we speed it up? added 216 characters in body Feb 18 answered Why is ListPlot[] so slow for coordinate pairs? Can we speed it up? Feb 18 revised Why does Solve work in v9.0.1 but not in v10.3.1 added 9 characters in body; edited tags; edited title Feb 18 revised Why does Solve work in v9.0.1 but not in v10.3.1 added 9 characters in body; edited tags; edited title Feb 18 revised Why does Solve work in v9.0.1 but not in v10.3.1 added 9 characters in body; edited tags; edited title Feb 14 comment Problem with solving an optimal control system with Shooting Method Interesting…I'd like to mention that, v10 seems to be necessary to solve the equation with the simpler solution, in v9.0.1 and v8.0.4 it failed. And the Expand seems to be redundant, at least according to my test on Wolfram Cloud. BTW, how did you find the good initial guess for the not-that-simple solution? Feb 13 revised Error propagation code deleted 1 character in body Feb 13 comment Error propagation code @DineshKumar Glad it helps. If you feel satisfied with my answer, you can vote it up by clicking the gray triangles and accept it by clicking the checkmark sign. Feb 13 revised Declaring functions in NDSolve? edited tags; edited title Feb 13 answered Declaring functions in NDSolve? Feb 13 comment How to handle a special Neumann-like boundary condition in NDSolve? @LCFactorization ?NumericQ is necessary to suppress the warning, if you don't mind the warning, simply use solL[xl_]. There're many examples for the usage of ?NumericQ in this site, you can have a search. Feb 13 comment How to handle a special Neumann-like boundary condition in NDSolve? @LCFactorization It's just derivative symbol, when xL gets a numeric value, solL[xl] will evaluate to a InterpolatingFunction. As to the reading material part, have you ever read Leonid Shifrin's excellent book? Here's the unfinished Chinese edition: tieba.baidu.com/p/3230448463 Feb 12 comment How to handle a special Neumann-like boundary condition in NDSolve? @LCFactorization See my edit. If you still have difficulty in understanding, evaluate solL[14] alone and check the output. Notice that precisely speaking, $x_0$ is not undetermined, but to be determined.