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  • 0 posts edited
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  • 26 votes cast
Jul
30
comment Substitute a function's definition for its name
@Guesswhoitis.: Can you explain how to do this? I recognized the (potential) problem of clashing variables but don't know how to handle this in Mathematica. (I can handle it in other languages, but my Math'ca isn't so good yet.)
Jul
30
accepted Substitute a function's definition for its name
Jul
30
asked Substitute a function's definition for its name
Dec
4
comment Inverse of LogIntegral
Works great, thanks! I tweaked the WorkingPrecision and PrecisionGoal upward and all was good.
Dec
4
accepted Inverse of LogIntegral
Dec
4
comment Inverse of LogIntegral
@DanielLichtblau: Thanks. (Maybe that should be an answer.) Mathematica is still giving me answers I don't believe (say, integrating up to 10^200 giving an answer of 2*10^7 instead of < 0.1) but at this point it seems hopeless. At least it works for small numbers.
Dec
4
comment Inverse of LogIntegral
(The true answer should be about 0.01125, or 19 orders of magnitude smaller.)
Dec
4
comment Inverse of LogIntegral
@DanielLichtblau: That's not a sensible answer, though. The li^{-1}(x) > x (in fact ~ x log x), so the integral should be less than the integral of 1/x over the same region, which is about 4.6.
Dec
4
comment Inverse of LogIntegral
@Artes: With an NIntegrate::inumr error. I've edited in code.
Dec
4
revised Inverse of LogIntegral
expand, as requested
Dec
4
asked Inverse of LogIntegral
Aug
5
comment Use of Strassen's algorithm
@TysonWilliams: BLAS does use Strassen in DGEMMS*. But Daniel's description of why to avoid that algorithm for floating-point calculations is apt.
Jul
2
awarded  Curious
May
28
awarded  Nice Question
May
22
comment How do I get Mathematica to return a function call unevaluated?
Hah! So at least I wasn't too far off the mark, just careless. Thanks for pointing this out!
May
22
awarded  Yearling
May
22
comment How do I get Mathematica to return a function call unevaluated?
@gpap: What do you get for AlgebraicQ /@ {7, Pi, Pi + E, I}?
May
22
comment How do I get Mathematica to return a function call unevaluated?
@gpap: I can't imagine how, honestly. I mean, clearly that should work if I gave it a non-Real, but for a Real it should return Element[x, Algebraics] because that's what you're telling it to return. Very strange, I'd be interested to learn more about this case.
May
22
revised How do I get Mathematica to return a function call unevaluated?
final answer
May
22
revised How do I get Mathematica to return a function call unevaluated?
flesh out