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Jan
28
comment The inverse Fourier transform of a rather complex function
Because t is actually discrete I tried to table the values of t and then calculating the inverse transformation with u being the only variable in the function f. Why not just use Fourier and InverseFourier since your data is discrete?
Jan
28
comment Does mixed-paradigm functional programming have more advantages in numerical simulation?
@MichaelE2 mixed programming is basically when the code looks like it was written in Matlab or Fortran and converted to Mathematica syntax.
Jan
28
comment Graphics3D: Objects with holes
@kguler nice. To answer OP question, then one can just do cub1 = Cuboid[{0, 0, 0}, {20, 2, 20}]; cub2 = Cuboid[{12, 0, 8}, {17, 2, 17}]; r2 = RegionDifference[cub1, cub2]; RegionPlot3D[r2] !Mathematica graphics but the edges need some work. Original question at community.wolfram.com/groups/-/m/t/430092?p_p_auth=EAP2rQun
Jan
28
comment Does mixed-paradigm functional programming have more advantages in numerical simulation?
@Mr.Wizard I see. I thought meta is about those meta-physics like questions about Mathematica. I see questions like What third-party packages do you use? and such. Any way. it was a suggestion.
Jan
28
comment No legends in parametric plot
see parametricplot-and-plotlegends-dont-seem-to-cooperate
Jan
28
comment Does mixed-paradigm functional programming have more advantages in numerical simulation?
This might be better asked in Meta ?
Jan
28
comment How can I change variable passed to a function?
I think a better way to do this is to make a local variable in the module, assign that the value of the input, then make modification on the local variable, and return that at the end. This is in the spirit of how Mathematica programming is done.
Jan
27
comment Testing for a vector of reals
David, your solution returns True for realVector[{1, 2, 3}], I think the OP wants this to return False. This happens because integer also returns True for Element[#,Reals], so a Head test is needed.
Jan
26
comment What's real analogue for FromDigits?
RealDigits? as in RealDigits[ToExpression["1234.234532"]] gives {{1, 2, 3, 4, 2, 3, 4, 5, 3, 2, 0, 0, 0, 0, 0, 0}, 4}
Jan
24
comment Problem with control structures on getting root values on array
it is not too clear what you are asking. But why not create the list you want, and at the end use DeleteDuplicates to remove duplicates.
Jan
24
comment Maximize[Cos[x - 1], x] is not evaluated
Strange. Wonder why this works Maximize[Cos[x - 1.], x] giving {1., {x -> 1.}}
Jan
24
comment ControlType -> None Vs. Module inside Manipulate (i.e. making everything local)
If you make the variables local to a Module inside Manipulate expression, then their values are no longer saved between refreshes of the expression. So you can't use them to store counters and other values that you want to remain saved as the simulation is running. Basically a new clean copy of these variables are made each time the expression is refreshed. So, rule of thumb: If you want to save the value of something between refreshes, you need to use {{x,0},None}. For (2), you should not make variables in Initializations. Only function definitions. Variables there become global.
Jan
19
comment Evaluate the Limit
Try Limit[((1 + 3 x)/(1 + 4 x^2 + 3 x^4))^3, x -> 1] this gives 1/8
Jan
19
comment Solving a second order non-linear differential equation
@Dr.WolfgangHintze For a symbolic solution try to DSolve the ODE without initial conditions. You will find the Inverse function of Integrals containing the error function Erf On which version M gave solution to this? Using version 10.02, it does not. It returns unevaluated. screen shot: !Mathematica graphics
Jan
18
comment PDE: Solving Burgers' equation with initial value given by a self consistency equation
the function $m(x)$ is defined in terms of itself?
Jan
17
comment Integrating a compound expression
M can't find analytical antiderivative. you can try different upper limits, build table of data, and try to do an interpolation function of the result.
Jan
17
comment Integrating a compound expression
is there something I could do and solve the integral you can try numerical integration. You would need to assign numerical value for the symbols. btw, you have typos in there. BesselJ is written as Besse1J. There is no digit 1 in the name, it is the letter l. Here is the code: expr = (a r Exp[-r] - b r Sin[k (r - d)] Exp[-r]) BesselJ[0, k r];, with numerical integration it works: NIntegrate[expr /. {k -> 1, a -> 1, d -> 2, b -> 3}, {r, 0, 10}] gives 1.49
Jan
17
comment Parsing string with nested information
can you please enter the problem is Mathematica synatx? Is the problem meant to be: problem = a { b { c d } e } a a { b b c c } ? I do not understand what path node list of the tree information here. You mean TreeForm ? can you give a link that explains what it is?
Jan
15
comment AdjacencyMatrix: Unexpected output
it is correct. The node numbering in the matrix are actually listed as VertexList[r] , which is {1, 2, 4, 3, 5, 6, 7}
Jan
15
comment How to accumulate elements in a list using Reap and Sow
Is this what you mean? AbsoluteTiming[ Last@Reap@Do[ Sow[{}]; If[i > 10, Sow[RandomReal[]]; Do[ If[RandomReal[] >= p, Sow[RandomReal[]] ], {j, 1, i}] ], {i, 1, T} ] ]