Wolfram Mathematica

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xzczd

02:04

@zhk Try the following:

sol[x_] := Module[{y},
  NDSolveValue[{2.5 - (0.25 + 0.5 I) w[y] + (1. + 0.1 I) (w^\[Prime]\[Prime])[y] == 0,
    w[1 + 0.1 Sin[0.1 x]] == 0, w[-1 - 0.1 Sin[0.1 x]] == 0},
   w, {y, -1 - 0.1 Sin[0.1 x], 1 + 0.1 Sin[0.1 x]}]]

helper[x_, y_] :=
 Piecewise[{{sol[x][y], -1 - 0.1 Sin[0.1 x] <= y <= 1 + 0.1 Sin[0.1 x]}}, 0]

dat = Re@Table[helper[x, y], {x, -10, 10, 1/10}, {y, -10, 10, 1/10}] // ListPlot3D

The key point is the Module, without it, the code will fail, because Plot3D and Table internally use Block to localize variable (in this case x and y) so the y in NDSolve is influenced. You can try removing the Module and see what will happen.

zhk

02:52

@xzczd it generates plot but the x and y axis vary from 0..200 which suppose to vary x=-10..10, y=-1 - 0.1 Sin[0.1 x] <= y <= 1 + 0.1 Sin[0.1 x]

zhk

03:15

@xzczd I got that right now, with this dat = Partition[
Flatten[Table[{x, y, Re@helper[x, y]}, {x, 0, 1, 1/5}, {y, -1, 1, 1/5}]], 3]
But why fixing y when its not fixed

zhk

03:36

@xzczd thx dear. its perfect

xzczd

03:48

@zhk Oh you want y to be between that interval in the plot, too? Then this should be more suitable:

Clear@sol
sol[x_] := sol[x] =
  Module[{y},
   NDSolveValue[{2.5 - (0.25 + 0.5 I) w[y] + (1. + 0.1 I) w''[y] == 0,
     w[1 + 0.1 Sin[0.1 x]] == 0, w[-1 - 0.1 Sin[0.1 x]] == 0},
    w, {y, -1 - 0.1 Sin[0.1 x], 1 + 0.1 Sin[0.1 x]}]]

Flatten[Re@Table[{x, y, sol[x][y]}, {x, -10, 10, 2 10/100}, {y, -1 - 0.1 Sin[0.1 x],
     1 + 0.1 Sin[0.1 x], 2 (1 + 0.1 Sin[0.1 x])/100}], 1] // ListPlot3D

zhk

@xzczd its fantastic! thx alot dear

7 hours later…

Jacob Akkerboom

10:53

This tutorial is broken for me (it is also in the doc center at WebServices/tutorial/AmazonExample). I didn't really try to understand it, but I think something goes wrong when evaluating the code cell, i.e. in the very first step. Does it work for anyone else?

2 hours later…

kirma

12:44

Important Friday question popped to my mind: what would happen if one would place a bottle of vodka in a clear glass bottle on a low earth orbit? Would it boil, would it freeze, would it do both depending on which dominates first, sun or shade, or would it magically stay inbetween?

Assuming an airtight bottle with normal air pressure inside, of course.

2 hours later…

Andrei Onoie

15:04

Hey, does anyone know why Limit[Integral[1/Sqrt[x^3 + x + 1], {x, n, n + 1}], n -> Infinity] doens't compute ?

J. M.

15:32

@kirma Sounds like an xkcd question. :D

kirma

15:51

@J.M. Yep, that came to my mind, too.

2 hours later…

Semiclassical

17:57

Suppose I've got a graph which I know to be bipartite (through BipartiteGraphQ). Is there an easy way to determine which vertices are in which partition?

...oh, duh. of course there is. just use graph distance. Ignore me!