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Sep 19, 2019 at 6:10 comment added Federico Poloni Consider asking on Computational Science: there are more experts there on actually computing stuff numerically, and I wouldn't be surprised if someone has already encountered this exact same problem.
Sep 19, 2019 at 4:04 history edited Michael Hardy CC BY-SA 4.0
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Jul 22, 2016 at 5:48 comment added Michael @MattF.: Does indefinite integral has the closed form? I won't integrate to $\infty$.
Jul 22, 2016 at 5:46 comment added Michael @BrianBorchers: Things like that, but possibly with different values of $c$ in the kernel of $e^{-x^c-y^c}$. The case $c=2$, a.k.a. Gaussian distribution, is the one that led to the question and is the most useful for this application. However, the case $c=1.5$, a.k.a. Holtsmark distribution, is also very useful in that context.
Jul 22, 2016 at 4:23 comment added user44143 If all you need is the definite integral $\int_{-\infty}^{\infty} \exp(-x^2)\,\text{erf}(x+a)\,dx$, it has the closed form $\sqrt{\pi}\, \text{erf}(a/\sqrt{2})$. Mathematica does not know this, but it is 4.3.13 in Geller and Ng's paper at nvlpubs.nist.gov/nistpubs/jres/73B/jresv73Bn1p1_A1b.pdf. You can prove it by expanding erf as an integral of $y$, and then changing variables with a 45-degree rotation of the $xy$-plane.
Jul 22, 2016 at 4:08 answer added Manfred Weis timeline score: 0
Jul 22, 2016 at 0:48 comment added Brian Borchers You'd do well to explain exactly what integral you actually want to evaluate. It seems unlikely that the strategy you're suggesting would be optimal. Is it just $\int_{-\infty}^{c} e^{-x^2 }\mbox{erf}(x+a)dx$?
Jul 22, 2016 at 0:30 comment added Michael @BrianBorchers: edited the question with the reason why I need that.
Jul 22, 2016 at 0:30 history edited Michael CC BY-SA 3.0
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Jul 22, 2016 at 0:13 comment added Brian Borchers Do you need to compute the Gaussian probability density or the comulative desnity (integral of the pdf from $-\infty$ to $x$) The former is trivial using an $\exp$ library function. The second is actually somewhat of a challenge.
Jul 21, 2016 at 23:10 answer added J.J. Green timeline score: 3
Jul 21, 2016 at 22:12 history asked Michael CC BY-SA 3.0