Problem with interpolating function returned by NDEigensystemFindRoot gives strange results when used on an interpolating function with vector outputIntegrating Squared of Interpolating Function with respect to one variableFunctionInterpolation with vector output and scalar inputHow to speed up NIntegrate when using an interpolating function output from NDEigensystem?3DPlot, Logarithmic x and y axes, Interpolating functionHow to quickly evaluate the same interpolating function many times?How to take derivative of the argument of an interpolating functionUsing NDEigensystem to find 100 eigenvaluesUsing multiple boundary conditions with NDEigensystemHow to increase the integration domain of NDEigensystem without a “non-Hermitian” error?
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Problem with interpolating function returned by NDEigensystem
FindRoot gives strange results when used on an interpolating function with vector outputIntegrating Squared of Interpolating Function with respect to one variableFunctionInterpolation with vector output and scalar inputHow to speed up NIntegrate when using an interpolating function output from NDEigensystem?3DPlot, Logarithmic x and y axes, Interpolating functionHow to quickly evaluate the same interpolating function many times?How to take derivative of the argument of an interpolating functionUsing NDEigensystem to find 100 eigenvaluesUsing multiple boundary conditions with NDEigensystemHow to increase the integration domain of NDEigensystem without a “non-Hermitian” error?
.everyoneloves__top-leaderboard:empty,.everyoneloves__mid-leaderboard:empty,.everyoneloves__bot-mid-leaderboard:empty margin-bottom:0;
$begingroup$
I'm trying to evaluate interpolating function returned by NDEigensystem at a point but Mathematica won't evaluate it.
vals, funs = NDEigensystem[-Laplacian[u[x], x], u[x], x, 0, [Pi], 4];
f = funs[[3]] (*3rd eigenfunction*)
Plot[f[x], x, 0, Pi] (*this plot returns blank plot*)
Plot[f, x, 0, Pi] (*this plot works fine*)
f[2]
As you can see, f[2] is not evaluated. Any help with the problem with the plot and function evaluation would be appreciated.
interpolation finite-element-method
edited Jul 15 at 13:33
user21
22.7k7 gold badges66 silver badges107 bronze badges
asked Jul 15 at 12:30
Omar NagibOmar Nagib
1234 bronze badges
$endgroup$
add a comment |
$begingroup$
I'm trying to evaluate interpolating function returned by NDEigensystem at a point but Mathematica won't evaluate it.
vals, funs = NDEigensystem[-Laplacian[u[x], x], u[x], x, 0, [Pi], 4];
f = funs[[3]] (*3rd eigenfunction*)
Plot[f[x], x, 0, Pi] (*this plot returns blank plot*)
Plot[f, x, 0, Pi] (*this plot works fine*)
f[2]
As you can see, f[2] is not evaluated. Any help with the problem with the plot and function evaluation would be appreciated.
interpolation finite-element-method
edited Jul 15 at 13:33
user21
22.7k7 gold badges66 silver badges107 bronze badges
asked Jul 15 at 12:30
Omar NagibOmar Nagib
1234 bronze badges
$endgroup$
add a comment |
$begingroup$
I'm trying to evaluate interpolating function returned by NDEigensystem at a point but Mathematica won't evaluate it.
vals, funs = NDEigensystem[-Laplacian[u[x], x], u[x], x, 0, [Pi], 4];
f = funs[[3]] (*3rd eigenfunction*)
Plot[f[x], x, 0, Pi] (*this plot returns blank plot*)
Plot[f, x, 0, Pi] (*this plot works fine*)
f[2]
As you can see, f[2] is not evaluated. Any help with the problem with the plot and function evaluation would be appreciated.
interpolation finite-element-method
edited Jul 15 at 13:33
user21
22.7k7 gold badges66 silver badges107 bronze badges
asked Jul 15 at 12:30
Omar NagibOmar Nagib
1234 bronze badges
$endgroup$
I'm trying to evaluate interpolating function returned by NDEigensystem at a point but Mathematica won't evaluate it.
vals, funs = NDEigensystem[-Laplacian[u[x], x], u[x], x, 0, [Pi], 4];
f = funs[[3]] (*3rd eigenfunction*)
Plot[f[x], x, 0, Pi] (*this plot returns blank plot*)
Plot[f, x, 0, Pi] (*this plot works fine*)
f[2]
As you can see, f[2] is not evaluated. Any help with the problem with the plot and function evaluation would be appreciated.
interpolation finite-element-method
interpolation finite-element-method
edited Jul 15 at 13:33
user21
22.7k7 gold badges66 silver badges107 bronze badges
asked Jul 15 at 12:30
Omar NagibOmar Nagib
1234 bronze badges
edited Jul 15 at 13:33
user21
22.7k7 gold badges66 silver badges107 bronze badges
asked Jul 15 at 12:30
Omar NagibOmar Nagib
1234 bronze badges
edited Jul 15 at 13:33
user21
22.7k7 gold badges66 silver badges107 bronze badges
edited Jul 15 at 13:33
user21
22.7k7 gold badges66 silver badges107 bronze badges
edited Jul 15 at 13:33
user21
22.7k7 gold badges66 silver badges107 bronze badges
22.7k7 gold badges66 silver badges107 bronze badges
asked Jul 15 at 12:30
Omar NagibOmar Nagib
1234 bronze badges
asked Jul 15 at 12:30
Omar NagibOmar Nagib
1234 bronze badges
asked Jul 15 at 12:30
Omar NagibOmar Nagib
1234 bronze badges
1234 bronze badges
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
$begingroup$
Change u[x] to u
vals, funs =NDEigensystem[-Laplacian[u[x], x], u , x, 0, [Pi], 4]
now
Plot[funs[[3]][x],x,0,Pi]
does what you are looking for.
To plot all the eigenfunctions try Plot[Through[funs[x]],x,0,Pi]
answered Jul 15 at 12:57
Ulrich NeumannUlrich Neumann
12.3k7 silver badges19 bronze badges
$endgroup$
$begingroup$
Thank you so much, this fixed my problem.
$endgroup$
– Omar Nagib
Jul 15 at 13:33
$begingroup$
You're welcome!
$endgroup$
– Ulrich Neumann
Jul 15 at 13:33
$begingroup$
On a related note, how can I define new functions using my interpolating function f (or manipulate interpolating functions in general)? For example in my above code, if I define ff=f+2 or ff=2*f, I'm not able to evaluate this function (e.g., ff[2] does not evaluate). Or how can I define new function ff= Sin[x]*f for example?
$endgroup$
– Omar Nagib
Jul 15 at 13:50
1
$begingroup$
Tryff = FunctionInterpolation[2 funs[[3]][x], x, 0, Pi]orfff = Function[x, funs[[3]][x] + 2]
$endgroup$
– Ulrich Neumann
Jul 15 at 13:53
1
$begingroup$
There are no errors in both variants( of my comment). Perhaps the second variant is preferable.
$endgroup$
– Ulrich Neumann
Jul 15 at 14:09
|
show 1 more comment
Your Answer
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
Change u[x] to u
vals, funs =NDEigensystem[-Laplacian[u[x], x], u , x, 0, [Pi], 4]
now
Plot[funs[[3]][x],x,0,Pi]
does what you are looking for.
To plot all the eigenfunctions try Plot[Through[funs[x]],x,0,Pi]
answered Jul 15 at 12:57
Ulrich NeumannUlrich Neumann
12.3k7 silver badges19 bronze badges
$endgroup$
$begingroup$
Thank you so much, this fixed my problem.
$endgroup$
– Omar Nagib
Jul 15 at 13:33
$begingroup$
You're welcome!
$endgroup$
– Ulrich Neumann
Jul 15 at 13:33
$begingroup$
On a related note, how can I define new functions using my interpolating function f (or manipulate interpolating functions in general)? For example in my above code, if I define ff=f+2 or ff=2*f, I'm not able to evaluate this function (e.g., ff[2] does not evaluate). Or how can I define new function ff= Sin[x]*f for example?
$endgroup$
– Omar Nagib
Jul 15 at 13:50
1
$begingroup$
Tryff = FunctionInterpolation[2 funs[[3]][x], x, 0, Pi]orfff = Function[x, funs[[3]][x] + 2]
$endgroup$
– Ulrich Neumann
Jul 15 at 13:53
1
$begingroup$
There are no errors in both variants( of my comment). Perhaps the second variant is preferable.
$endgroup$
– Ulrich Neumann
Jul 15 at 14:09
|
show 1 more comment
$begingroup$
Change u[x] to u
vals, funs =NDEigensystem[-Laplacian[u[x], x], u , x, 0, [Pi], 4]
now
Plot[funs[[3]][x],x,0,Pi]
does what you are looking for.
To plot all the eigenfunctions try Plot[Through[funs[x]],x,0,Pi]
answered Jul 15 at 12:57
Ulrich NeumannUlrich Neumann
12.3k7 silver badges19 bronze badges
$endgroup$
$begingroup$
Thank you so much, this fixed my problem.
$endgroup$
– Omar Nagib
Jul 15 at 13:33
$begingroup$
You're welcome!
$endgroup$
– Ulrich Neumann
Jul 15 at 13:33
$begingroup$
On a related note, how can I define new functions using my interpolating function f (or manipulate interpolating functions in general)? For example in my above code, if I define ff=f+2 or ff=2*f, I'm not able to evaluate this function (e.g., ff[2] does not evaluate). Or how can I define new function ff= Sin[x]*f for example?
$endgroup$
– Omar Nagib
Jul 15 at 13:50
1
$begingroup$
Tryff = FunctionInterpolation[2 funs[[3]][x], x, 0, Pi]orfff = Function[x, funs[[3]][x] + 2]
$endgroup$
– Ulrich Neumann
Jul 15 at 13:53
1
$begingroup$
There are no errors in both variants( of my comment). Perhaps the second variant is preferable.
$endgroup$
– Ulrich Neumann
Jul 15 at 14:09
|
show 1 more comment
$begingroup$
Change u[x] to u
vals, funs =NDEigensystem[-Laplacian[u[x], x], u , x, 0, [Pi], 4]
now
Plot[funs[[3]][x],x,0,Pi]
does what you are looking for.
To plot all the eigenfunctions try Plot[Through[funs[x]],x,0,Pi]
answered Jul 15 at 12:57
Ulrich NeumannUlrich Neumann
12.3k7 silver badges19 bronze badges
$endgroup$
Change u[x] to u
vals, funs =NDEigensystem[-Laplacian[u[x], x], u , x, 0, [Pi], 4]
now
Plot[funs[[3]][x],x,0,Pi]
does what you are looking for.
To plot all the eigenfunctions try Plot[Through[funs[x]],x,0,Pi]
answered Jul 15 at 12:57
Ulrich NeumannUlrich Neumann
12.3k7 silver badges19 bronze badges
answered Jul 15 at 12:57
Ulrich NeumannUlrich Neumann
12.3k7 silver badges19 bronze badges
answered Jul 15 at 12:57
Ulrich NeumannUlrich Neumann
12.3k7 silver badges19 bronze badges
answered Jul 15 at 12:57
Ulrich NeumannUlrich Neumann
12.3k7 silver badges19 bronze badges
12.3k7 silver badges19 bronze badges
$begingroup$
Thank you so much, this fixed my problem.
$endgroup$
– Omar Nagib
Jul 15 at 13:33
$begingroup$
You're welcome!
$endgroup$
– Ulrich Neumann
Jul 15 at 13:33
$begingroup$
On a related note, how can I define new functions using my interpolating function f (or manipulate interpolating functions in general)? For example in my above code, if I define ff=f+2 or ff=2*f, I'm not able to evaluate this function (e.g., ff[2] does not evaluate). Or how can I define new function ff= Sin[x]*f for example?
$endgroup$
– Omar Nagib
Jul 15 at 13:50
1
$begingroup$
Tryff = FunctionInterpolation[2 funs[[3]][x], x, 0, Pi]orfff = Function[x, funs[[3]][x] + 2]
$endgroup$
– Ulrich Neumann
Jul 15 at 13:53
1
$begingroup$
There are no errors in both variants( of my comment). Perhaps the second variant is preferable.
$endgroup$
– Ulrich Neumann
Jul 15 at 14:09
|
show 1 more comment
$begingroup$
Thank you so much, this fixed my problem.
$endgroup$
– Omar Nagib
Jul 15 at 13:33
$begingroup$
You're welcome!
$endgroup$
– Ulrich Neumann
Jul 15 at 13:33
$begingroup$
On a related note, how can I define new functions using my interpolating function f (or manipulate interpolating functions in general)? For example in my above code, if I define ff=f+2 or ff=2*f, I'm not able to evaluate this function (e.g., ff[2] does not evaluate). Or how can I define new function ff= Sin[x]*f for example?
$endgroup$
– Omar Nagib
Jul 15 at 13:50
1
$begingroup$
Tryff = FunctionInterpolation[2 funs[[3]][x], x, 0, Pi]orfff = Function[x, funs[[3]][x] + 2]
$endgroup$
– Ulrich Neumann
Jul 15 at 13:53
1
$begingroup$
There are no errors in both variants( of my comment). Perhaps the second variant is preferable.
$endgroup$
– Ulrich Neumann
Jul 15 at 14:09
$begingroup$
Thank you so much, this fixed my problem.
$endgroup$
– Omar Nagib
Jul 15 at 13:33
$begingroup$
Thank you so much, this fixed my problem.
$endgroup$
– Omar Nagib
Jul 15 at 13:33
$begingroup$
You're welcome!
$endgroup$
– Ulrich Neumann
Jul 15 at 13:33
$begingroup$
You're welcome!
$endgroup$
– Ulrich Neumann
Jul 15 at 13:33
$begingroup$
On a related note, how can I define new functions using my interpolating function f (or manipulate interpolating functions in general)? For example in my above code, if I define ff=f+2 or ff=2*f, I'm not able to evaluate this function (e.g., ff[2] does not evaluate). Or how can I define new function ff= Sin[x]*f for example?
$endgroup$
– Omar Nagib
Jul 15 at 13:50
$begingroup$
On a related note, how can I define new functions using my interpolating function f (or manipulate interpolating functions in general)? For example in my above code, if I define ff=f+2 or ff=2*f, I'm not able to evaluate this function (e.g., ff[2] does not evaluate). Or how can I define new function ff= Sin[x]*f for example?
$endgroup$
– Omar Nagib
Jul 15 at 13:50
1
1
$begingroup$
Try
ff = FunctionInterpolation[2 funs[[3]][x], x, 0, Pi] or fff = Function[x, funs[[3]][x] + 2]$endgroup$
– Ulrich Neumann
Jul 15 at 13:53
$begingroup$
Try
ff = FunctionInterpolation[2 funs[[3]][x], x, 0, Pi] or fff = Function[x, funs[[3]][x] + 2]$endgroup$
– Ulrich Neumann
Jul 15 at 13:53
1
1
$begingroup$
There are no errors in both variants( of my comment). Perhaps the second variant is preferable.
$endgroup$
– Ulrich Neumann
Jul 15 at 14:09
$begingroup$
There are no errors in both variants( of my comment). Perhaps the second variant is preferable.
$endgroup$
– Ulrich Neumann
Jul 15 at 14:09
|
show 1 more comment
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