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http://community.wolfram.com/groups/-/m/t/1206507
When I launch wolframscript form shell, it always prints "Updating from Wolfram Research server ..." after In[1]:=
Like this:
$ wolframscript
Wolfram Language 11.2.0 Engine for Mac OS X x86 (64-bit)
Copyright 1988-2017 Wolfram Research, Inc.
In[1]:= Updating from Wolfram Research server ...
If I type `wolframscript -code 1+1 > foo.txt`, everything is OK.
`cat foo.txt` will return:
2
But if I type `wolframscript -code 9^9^9 > bar.txt`, "Updating from Wolfram Research server ..." will be added at the beginning of bar.txt.
`head -c 100 bar.txt` will return:
Updating from Wolfram Research server ...
4281247731757470480369871159305635213390554822414435141747
Waiting or disconnecting the network can't solve this problem.Zhou Zhuang2017-10-21T01:39:34ZSignificant digits
http://community.wolfram.com/groups/-/m/t/1205988
hz = N[28 2^(-(n/6)) , {Infinity, 3}];
Column[Table[{n, hz}, {n, 36, 41}]]
Why do I get two different types of results digitwise?Nelson Zink2017-10-21T00:01:44ZMathematica's benefits and difficulties
http://community.wolfram.com/groups/-/m/t/1205525
Hi! We are college students and we are doing a project that we have to talk about the software Mathematica. We would like to know the difficulties and benefits that you found while using the program. Thank you!!Amanda Correa2017-10-19T11:11:06ZGet gradient of PredictorFunction with respect to input?
http://community.wolfram.com/groups/-/m/t/1203073
For special forms of the PredictorFunction, there is an analytical formula for the gradient of the predictor wrt the input, x. For example, in a Gaussian Process, the prediction at $x$ is the posterior mean $m(x)$, and it is a linear combination of the kernel used
$$ m(x) = \sum a_{n} * k(x_n, x) $$
Hence, it is possible to obtain analytically the gradient of the mean wrt $x$ by taking a linear combination of the gradient of $k$. I was wondering, is it already implemented in the Wolfram function `Predict[]` or maybe `PredictorFunction[]` ? If not, is there an easy way to find the pieces needed? E.g. kernel parameters and kernel used, and possibly its gradient wrt $x$?
ThanksUmberto Noe2017-10-16T01:41:36ZUse NIntegrate with vectors?
http://community.wolfram.com/groups/-/m/t/1202204
Is there a way to get Mathematica to provide a meaningful answer - perhaps semi-numerically - for the following numerical integral over vectors? Note that it is OK to assume a value for \Alpha. Additionally the vector $\vec{x}$ is not being integrated over. So, if absolutely essential, different values of $\vec{x}$ could be taken for the numerical integration.
$Assumptions = Element[p1v | p3v | p4v | p5v | xv, Vectors[3, Reals]];
a = Simplify[ReleaseHold[Hold[E^((-I)*p1v . xv)]]]
b = Simplify[ReleaseHold[Hold[(p1v . p1v + p3v . p3v)/
((p3v - p1v)*(p3v - p1v)*(\[Alpha]^2*p3v . p3v + 1)^2)]]]
jj = FullSimplify[a*b]
Now, the following symbolic integral doesn't seem to work, i.e. Mathematica just spits back the input
Integrate[(p1v . p1v + p3v . p3v)/(E^(I*p1v . xv)*
((p1v - p3v)^2*(1 + \[Alpha]^2*p3v . p3v)^2)),
{p1v, -Infinity, Infinity}, {p3v, -Infinity, Infinity}]
but neither do the following NIntegrate commands work
NIntegrate[(p1v . p1v + p3v . p3v)/(E^(I*p1v . xv)*
((p1v - p3v)^2*(1 + p3v . p3v)^2)), {p1v, 0, 1}, {p3v, 0, 1},
{xv, 0, 1}]
NIntegrate::inumr: The integrand (E^(-I p1v.xv) (p1v.p1v+p3v.p3v))/((p1v-p3v)^2 (1+p3v.p3v)^2) has evaluated to non-numerical values for all sampling points in the region with boundaries {{0,1},{0,1},{0,1}}.
Note that above, \Alpha was taken to be zero, and a simultaneous integration over $\vec{x}$ was attempted, if Mathematica can't do any kind of semi-numerical integration.
The following NIntegrate doesn't work either - probably because I don't know how to make Mathematica perform a numerical integration with an algebraic parameter.
NIntegrate[(p1v . p1v + p3v . p3v)/(E^(I*p1v . xv)*
((p1v - p3v)^2*(1 + p3v . p3v)^2)), {p1v, 0, 1}, {p3v, 0, 1}]
NIntegrate::inumr: The integrand (E^(-I p1v.xv) (p1v.p1v+p3v.p3v))/((p1v-p3v)^2 (1+p3v.p3v)^2) has evaluated to non-numerical values for all sampling points in the region with boundaries {{0,1},{0,1}}.
If there is a way to conclusively know before integration whether the integrals are non-convergent, that would be very helpful, but that's also unknown to me how to do that in Mathematica.Arny Toynbee2017-10-12T16:51:05Z