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8h
comment Fitting data with interdependence
Might be useful to check responses and comments here.
8h
comment Finding planetary conjunctions with Mathematica (project-level)
It is very difficult to comment on code that is not shown. A guess is that you will need to restrict some functions to only operate on explicitly numeric input, e.g. earthangle[jd_?NumericQ,...] := ...
1d
comment Points on discriminant variety?
I think it is akin to the difference between Sylvester and Bezout formulation of ordinary resultants. One is larger, but more sparse. The use of Jacobian determinant corresponds to the smaller (only one polynomial...) denser (...but it's a very large polynomial) approach.
1d
comment Why am I getting different answers for integral depending on method?
I am not seeing the 54.16.. result. I am using version 10.latest.
1d
comment Points on discriminant variety?
How will that arbitrary v be specified? This is a bit of an unfamiliar for me. Seems mildly related to u-resultants, maybe.
1d
answered Points on discriminant variety?
1d
comment Points on discriminant variety?
I don't know, it seemed like a reasonable question to me. Just a bit underspecified. Maybe there is a concern that we not discriminate against varieties (one can never be too careful).
1d
awarded  Nice Answer
1d
comment Failure in use of SetPrecision with Filter
For what it's worth, I brought the warning messages to the attention of the Control developers. To me they look like uses of N[] in internal code, and very possibly are entirely benign (that's my guess at least).
1d
comment Failure in use of SetPrecision with Filter
Please do post it, I'm swamped.
1d
comment Points on discriminant variety?
You are interested in points on the zero set that satisfy what condition? Multiplicity, for particular gammaN values? Vanishing leading coefficients in a Groebner basis? Something else?
1d
comment Failure in use of SetPrecision with Filter
You might be able to make it give a result using Block[{$MinPrecision = np, $MaxPrecision = np},f2 = SetPrecision[e1, np];...] on the fdata2 part.
Aug
28
comment FindMaximum failing on a trivial problem
(1) It's not a bug. (2) As the error message states, domain constraints such as integrality are only supported in FindMinimum for linear programming. (3) The change from * to + made it into a linear problem. As others have noted.
Aug
28
comment Mathematica Lattice Reduce Command
@Guesswhoitis Actually it was implemented a few years ago, we just never told anyone. Was available via undocumented SystemOption. Some day I may even wrap up L1+ (if it doesn't wrap me up first).
Aug
28
comment Multivariate resultant in Mathematica?
Well, you are using purely symbolic coefficients in your example, so it is going to be a difficult one. Problems with rational coeffs might fare better, maybe allow for more polynomials and variables. Or maybe those crash. It's been a long time since I even looked (briefly) at that code; I didn't write it and was not up to the task of debugging it.
Aug
28
comment Multivariate resultant in Mathematica?
I am glad to see you located that function and also got sensible results. Or resultants. Whatever.
Aug
28
comment Mathematica Lattice Reduce Command
@Guesswhoitis I had no idea that was in the documentation (even worse, it had to be me that put it there). As of 10.2 we use a method due to Nguyen and Stehle. Sometimes referred to as L^2 (though there are now at least two such).
Aug
28
comment Keep leading/trailing zeroes (like Defer except with numbers) in a given number
I believe you can use results from Precision and Accuracy to assess number of significant figures.
Aug
27
comment Keep leading/trailing zeroes (like Defer except with numbers) in a given number
I should mention that all this is probably the wrong way to go about it. Check Precision and Accuracy and RealDigits; those should have what you need in order to get significant figures.
Aug
27
comment Keep leading/trailing zeroes (like Defer except with numbers) in a given number
You can, I think, manipulate the NumberForm by invoking ToString. Might take some fiddling around though.