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22h
comment Call library function in compile
I agree that it's a bug. When you get an unexpected StringJoin::string message by doing something that to all appearances should be perfectly allowable, I don't think we can describe it any other way.
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awarded  Enlightened
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awarded  Nice Answer
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comment Can I code a conditional jump between cells in a notebook?
@N.J.Evans f[x_, ...]["Tarragon"] := ... would be more versatile, due to the fact that one cannot define Hold* attributes that affect subvalues.
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comment Invoking WorkingPrecision slows down Eigenvalue calculation drastically?
If 128-bit precision is good enough for you, you might find some libraries that support IEEE long doubles.
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comment Invoking WorkingPrecision slows down Eigenvalue calculation drastically?
Why do you say it is arbitrarily selected? It is based on the 53-bit significand of an IEEE754-compliant machine (64-bit) double precision quantity. I suppose it is arbitrary in the sense that we have 64-bit processors rather than, say, 71-bit ones, but there are reasons for that standardization. Anyway, I would think the answer is probably no, unless you can find some libraries that can calculate eigenvalues at arbitrary precision. It is not trivial to do, so I'm not sure how many such even exist outside of software like Mathematica and Maple.
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comment Invoking WorkingPrecision slows down Eigenvalue calculation drastically?
@DanielLichtblau thanks. That is very useful.
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comment Invoking WorkingPrecision slows down Eigenvalue calculation drastically?
@DanielLichtblau in "Some Notes on Internal Implementation" it says, "For dense arrays, LAPACK algorithms extended for arbitrary precision are used when appropriate." In the past I have tended to take this statement quite literally, but given your comment, it seems in doubt--or, at least, if LAPACK has been extended, BLAS has not been, even though it is a dependency of LAPACK. What is your point of view about this?
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answered Invoking WorkingPrecision slows down Eigenvalue calculation drastically?
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awarded  Nice Answer
Aug
24
comment What is the best way to transfer arbitrary-precision reals using WSTP?
Do you mean binary-coded decimal (BCD)? I am not sure if there is any way to produce this in Mathematica. For that matter, a byte array is not so easy either. The only native arrays are of signed 64-bit integers. There is the undocumented RawArray object, but I don't know if it can be passed through MathLink, even if you can somehow represent a floating-point number in this way.
Aug
23
comment What is the best way to transfer arbitrary-precision reals using WSTP?
"Apparently not the best way"--why? As far as I know, it is the best way (simply because it is the only direct way) to do it using MathLink. But certainly a more efficient way would be preferable, and in that sense, it is a good question. Perhaps one can try partitioning the number into a list of digits in some large base and transfer a numerical array, but I'm not sure if GMP can easily reconstruct a number represented this way.
Aug
22
comment CUDALink not working on Linux-64 and Asus GTX460
Thank you for your contributions, although please note that it is extremely poor form to post identical answers to multiple questions. If you really think the question is a duplicate and can be answered identically, then flag it as such. I have upvoted one of your three answers (since it is obviously a good answer), but the other two (this one and this one) do not seem appropriate to their respective questions, i.e. the issue encountered by the OP was obviously different.
Aug
22
reviewed Close Create set of data from vector curve
Aug
22
comment Create set of data from vector curve
This is not a free coding service. Unless someone has already solved this problem for themselves, it is unlikely that you will find anyone willing to implement it for you. On the other hand, if you make a start, you will probably find someone willing to help. But at the least you are going to have to teach yourself something about SVG objects and coordinate systems. Bear in mind that SVG is a presentation format, and not intended to contain quantitative information, so your task is not a simple one given an arbitrary SVG file.
Aug
22
reviewed Leave Open Table generation with SetDelayed function
Aug
22
reviewed Leave Open slwcon and eincr in integrating multivariate Gaussian random variables
Aug
22
reviewed Close How to accelerate Simplify and Series?
Aug
22
comment How to accelerate Simplify and Series?
Let me be clearer: this question cannot be answered, apart from pure speculation, unless you give an actual example of f or a function like it. Performance of Series and Simplify is not necessarily related to the mathematical characteristics that you assume are relevant. As it is now, the only person in a position to answer your question is you. As to your numbered points: 1. probably not, but you can easily try the experiment yourself; 2. Parallelize does not work like that.
Aug
21
awarded  Enlightened