Andreas Lauschke
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 3h comment Applied Linear Algebra | Prove the intersection of two subspaces So many ways in M. RowReduce, MatrixRank, dimension of NullSpace, ... and the question looks like homework. Apr14 comment Can Enterprise Edition really encrypt code for distribution via CDF? @Kuba, sorry for the long wait, I was absent for a while. Yes, the key-based RSA encryption is indeed encryption. Parts of Encrypt seem to be bolted on to OpenSSL, although I can't tell yet to what extent OpenSSL is used. If it's coded correctly, it will probably be all right. A friend of mine informed me that the Windows version doesn't seem to encrypt RSA without the padding routine, contrary to the documentation, but as I'm not a Windows user, I couldn't check that. Tests with PowerMod show that the keys and exponents work correctly, so I'd call it encryption. Oct4 reviewed Approve Expand a rational function in a one degree partial fraction, but not include a two degree expression? Sep29 reviewed Approve ParametricNDSolve KKT Constraint Directly Sep28 revised Faster Integer Approximation of pi added 185 characters in body Sep28 answered Faster Integer Approximation of pi Sep28 comment Faster Integer Approximation of pi The best rational approximations to a real number are the continued fractions, a classic result. In fact, you can only get a better approximation than the convergent if you increase the denominator. There are numerous simple proofs/theorems about this, the earliest, to my knowledge, from Lagrange (unless you count Euclid in 300 BC, because the Euclidean algorithm gives you the c. f. approximation). So the comment from ybeltukov above and the answer from ubpqdn below are dead-on (as Rationalize gives you the c. f. approximation). Sep24 awarded Autobiographer Sep16 comment Kernel crashes when plotting $z=\sqrt{(x^2 + y^2)}^0$ completely agreed with previous commenters that "don't do that" is the wrong response. The kernel should NEVER crash, and for that it doesn't matter how the crash was produced. The crash itself is the problem. The existence of a work-around is never sufficient to accept a kernel crash. It's like saying "if a certain plane type repeatedly crashes, don't use the plane, drive by car". We can't acquit the faulty system just because we can adapt our behavior (how we cope with the problem). It's still a problem. Sep4 reviewed Approve What is the best distribution for my histogram? Aug24 reviewed Approve How do I set up conditions at infinity? Aug13 comment Is this 30% slowdown in Mathematica 10 due to DownValues lookup time? There will be a 10.0.1 not too long in the future, there's just too much problematic in M10. From what I hear through the grapevine, there should be a 10.0.1 not too far in the future. M10 has many performance problems of various types, and the cloud technology still has several shortcomings, and they know it. Aug7 awarded Custodian Aug7 reviewed Approve Substituting values in 3j symbols Jul31 comment BitShiftRight produces incorrect results in Version 10 part 2: If you were to use it recursively, parallel or not, you would only get 52 bits on each precision level. The two things could be related if M is using integers in the same schema as rationals with no modular remainder; it wouldn't be hard to screw up the bit arithmetic if everything was being stored in an array of IEEE 64 bit floating point numbers using Intel's vector system. When you apply DeveloperPackedArrayQ[v2] to the example you get True. Jul31 comment BitShiftRight produces incorrect results in Version 10 part 1: Here's a guess/suspicion I venture to suggest as a comment, which could be the cause. Try: max = \$MaxNumber. After trying to contemplate that magnitude for a moment: max = Log[2, max] is Log[2, max]. So to me it looks as if WRI may have implemented a precision scheme, using the IEEE 64 bit floating point algorithm recursively by using the parallel framework.IEEE 64 bit gets 53 bit precision by always using the same first bit. Jul25 comment Using J/Link with Wolfram Programming Cloud initial testing revealed that OnlineM lets you load JLink with Needs["JLink"], but then upon ReinstallJava[] the kernel quits. I've also seen that it uses Java 7 update 13, which is quite depressing, given that the current Java is Java 8 update 11 since Jul 15. I'd assume that CloudM uses the same as OnlineM, but haven't been able to test yet. Jul21 comment Mathematica policy for correctness of results a) What you describe is not warranty, it would be liability. b) WRI DOES actually provide warranty, if you read the terms. If the disk is broken, they'll send you a new one, and that is the maximum remedy. c) Liability in software is generally not offered, and if it's contractually agreed, then it's based on a custom contract, and not for standard software. But such contracts are rarely done, and the terms will usually specify things like free from liability, hold harmless, and indemnify. d) you really don't seem familiar with the regular business practices in the software industry. Jun28 awarded Yearling Mar11 comment Elliptic curve cryptography in Mathematica @Tyler: yes, I know Python is popular for crypto work. But you can't easily integrate it with M (at least to my knowledge), whereas with JLink it's right at your fingertips to leverage over from M to the JVM, and you mentioned "practical" in a comment.