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1
vote
0
answers
61
views
Why does the InterpolationPointsSubdivision method fails to calculate this integral correctly?
", ySpectrum["InterpolationPointsSubdivision",0.2,0.3] gives zero, while ySpectrum["AdaptiveMonteCarlo",0.2,0.3] is non-zero (as it should be, if looking at the initial data). … But how to make "InterpolationPointsSubdivision" work correctly? It does not work properly with non-rectangular regions of integration. …
5
votes
How to solve this integral equation using Mathematica?
1}];
var = Flatten[Table[co[i, j], {j, 0, jm, 1}, {i, 0, 2^j - 1, 1}]];
varM = Join[{co[-1, -1]}, var];
eq[x_] :=
Sum[NIntegrate[Cot[(x - t)/2]*h[t, i, 2^j], {t, -ac, x, ac},
Method -> {"InterpolationPointsSubdivision … ",
Method -> {"PrincipalValue", "SymbolicProcessing" -> 0}}]*
co[i, j], {j, 0, jm, 1}, {i, 0, 2^j - 1, 1}] +
NIntegrate[Cot[(x - t)/2]*h1[t], {t, -ac, x, ac},
Method -> {"InterpolationPointsSubdivision …
4
votes
Accepted
Plot nested integration of an InterpolatingFunction efficiently
= s}}], (* subtract singular part *)
{s, -L, x, L},
Method -> {"InterpolationPointsSubdivision", (* divide interval at nodes *)
"SymbolicProcessing" -> 0},
PrecisionGoal - … = xp}}], {xp, -L, x, L},
Method -> {"InterpolationPointsSubdivision",
"SymbolicProcessing" -> 0}, PrecisionGoal -> 4] +
dux*((2*L) Log[(L + x)/(L - x)])/π]];
Single-call timings …
3
votes
Integral of a Wavelet function
Verify how many interpolation points are used in the integration interval of interest:
Count[Flatten[derPhi["Grid"]], x_ /; 1/4 < x < 1/2]
63
We can then use the "InterpolationPointsSubdivision" … The count above is well within the default setting of "MaxSubregions", so that doesn't need to be adjusted:
NIntegrate[derPhi[x], {x, 1/4, 1/2},
Method -> {"InterpolationPointsSubdivision" …
5
votes
NIntegrate failed to converge and why?
You can specify the singularities sometimes with Method -> "InterpolationPointsSubdivision", but it does not work here, maybe because of the complexity of p1. …
3
votes
1
answer
342
views
Solving PDE and avoiding singularity
NumericQ, t_ /; t == 0] := (cnt++;
NIntegrate[inicos'''[xp]*Cot[\[Pi] (x - xp)/(2*L)], {xp, x - L, x, x + L},
Method -> {"InterpolationPointsSubdivision", Method -> "PrincipalValue"},
PrecisionGoal … NumericQ] := Function[x, cnt++;
NIntegrate[Interpolation[periodize@Transpose@{xv, uppp}, xp,
PeriodicInterpolation -> True]*Cot[\[Pi] (x - xp)/(2*L)], {xp, x - L, x, x + L},
Method -> {"InterpolationPointsSubdivision …
1
vote
Solving PDE and avoiding singularity
NumericQ, t_ /; t == 0] := (cnt++;
NIntegrate[inicos'''[xp]*Cot[\[Pi] (x - xp)/(2*L)], {xp, x - L, x, x + L},
Method -> {"InterpolationPointsSubdivision", Method -> "PrincipalValue"},
PrecisionGoal … NumericQ, t_ /; t == 0] := (cnt++;
NIntegrate[
inicos'''[xp]*Cot[\[Pi] (x - xp)/(2*L)], {xp, x - L, x, x + L},
Method -> {"InterpolationPointsSubdivision",
Method -> "PrincipalValue" …
4
votes
1
answer
457
views
How to speed up the integral in NDSolve?
NumericQ, t_ /; t == 0] := (cnt++;
c*NIntegrate[D[ic[xp], {xp, 3}]*Cot[\[Pi] (x - xp)/(2*L)], {xp, x - L, x, x + L},
Method -> {"InterpolationPointsSubdivision", Method -> {"PrincipalValue", " … NumericQ, t_ /; t == 0] := (cnt2++;
c*NIntegrate[D[ic[xp], {xp, 2}]*int[D[ic[xp], xp], x, t]*Cot[\[Pi] (x - xp)/(2*L)], {xp, x - L, x, x + L},
Method -> {"InterpolationPointsSubdivision", Method …
11
votes
Solving partial differential equation involving Hilbert transform
NumericQ, t_ /; t == 0] := (cnt++;
NIntegrate[-Cos[xp]/ (x - xp), {xp, x - L, x, x + L},
Method -> {"InterpolationPointsSubdivision",
Method -> "PrincipalValue"}, PrecisionGoal -> 8 … VectorQ, t_] := Function[x, cnt++;
NIntegrate[
Interpolation[periodize@Transpose@{xv, uppp}, xp,
PeriodicInterpolation -> True]/ (x - xp), {xp, x - L, x,
x + L}, Method -> {"InterpolationPointsSubdivision …
10
votes
Solving an integro-differential equation with Mathematica
NumericQ, t_ /; t == 0] := (cnt++;
NIntegrate[
D[0.1*Cos[\[Pi]/L*xp], {xp, 3}]*Cot[\[Pi] (x - xp)/(2*L)],
{xp, x - L, x, x + L},
Method -> {"InterpolationPointsSubdivision", Method … cnt++;
NIntegrate[
Interpolation[periodize@Transpose@{xv, uppp}, xp,
PeriodicInterpolation -> True]*Cot[\[Pi] (x - xp)/(2*L)],
{xp, x - L, x, x + L},
Method -> {"InterpolationPointsSubdivision …
3
votes
Accepted
Interpolation works slowly
weak singularities, which require dense sampling to get an accurate estimate or require the integration region to be broken up according to the pieces of the piecewise interpolation, which is what the "InterpolationPointsSubdivision … i1 = NIntegrate[
DistrToyInterpolated[thh, Eh], {thh, 0, Pi}, {Eh, 125, 3000},
Method -> {"InterpolationPointsSubdivision",
"MaxSubregions" -> 315*3000/5, (* slight overestimate from interpolation …
5
votes
Accepted
Can I obtain more precise integration of highly oscillating integral?
The "InterpolationPointsSubdivision" preprocessor of NIntegrate seems like the right move, but it was much faster and with a much better result to do a simple, straightforward implementation of an integration …
3
votes
Accepted
Integrating over colors
From here, we can use the sRGB conversion functions from this answer, and then use NIntegrate[] with the setting Method -> "InterpolationPointsSubdivision":
(* gamma correction *)
sRGBGamma = Function … 12.92 z, z <= 0.0031308}},
1.055 z^(1/2.4) - 0.055]],
Listable];
NIntegrate[Clip[#, {0, 1}]/λ^4, {λ, 385, 700},
Method -> "InterpolationPointsSubdivision …
-1
votes
3
answers
925
views
Problem with NIntegrate over a highly-oscillatory integrand
To do that, I the function
Si2[a_, b_] := NIntegrate[Sin[x - y]/(x y), {x, a, b}, {y, x, b},
AccuracyGoal -> 25, PrecisionGoal -> 25, WorkingPrecision -> 40,
MaxRecursion -> 1000000, Method -> "InterpolationPointsSubdivision … Note that I use the InterpolationPointsSubdivision method because I saw in various answers that it is a good method to evaluate numerically a highly-oscillatory integrand. …
1
vote
How to speed up integration of interpolation function?
opts = {{},
Method ->
"InterpolationPointsSubdivision", {Method -> {Automatic,
"SymbolicProcessing" -> 0}, PrecisionGoal -> 3}};
res =
Table[
With[{x = 5, y = 5, o1 = o},
Prepend …