Questions related to functional methods, e.g. functional differentiation and integration.
This tag is used for questions related to functional methods, e.g. functional differentiation and integration.
Questions tagged [functional]
39 questions
6
votes
1 answer
How to define a functional by the way it acts on its own output
I want to define a functional E by using the property E[ E[f[x]] ] := E[f[x]] for some arbitrary function f[x]. Meaning, that I want Mathematica to evaluate every expression E[ E[f[x]] ] to E[f[x]] for all functions f[x]. How do I make this in…
Demoncracy
- 63
- 3
6
votes
1 answer
How to compute symbolically the Legendre transform of a function?
Is it possible to compute symbolically the Legendre transform of a function in Mathematica?
I find no LegendreTransform function.
a06e
- 11,327
- 4
- 48
- 108
5
votes
4 answers
How do I define functionals in Mathematica?
When I write W[f_] := Integrate[f[x], {x, 0, π}] I may rightly conclude that
W[Sin] = 2, W[Cos] = 0, W[Log] = π (-1 + Log[π]) etc. But I am unable to define W[Sin + Cos] or W[Sin[Sin]] etc. Please help.
Quasar Supernova
- 1,678
- 8
- 13
2
votes
0 answers
Different delays in notebook and command-line?
I was surprised by the following sequence of expressions:
Remove[foo$, bar$];
foo$ = Function[Set[bar$, 42]];
At this point, I expected foo$ to be defined and bar$ not to be defined, because I had not called the function named foo$ yet. Indeed, the…
Reb.Cabin
- 8,661
- 1
- 34
- 62
1
vote
2 answers
Define a functional and nest it with its arguments
I'm looking for a definition of a functional f which works correctly with varying arguments t while it will be nested.
For example, I've the following code
f[g__[t__]] := g[t] + g[t - s]
For an input function in[t] I'll…
Drakonomikon
- 191
- 7