I found MurmurHash recently as one of the fastest, and MurmurHash3 is the new version of MurmurHash.
I also found the complete explanation of MurmurHash in a Diagram by Ian Boyd.
This diagram really looks awesome but I understand only a bit of it since I'm still a newbie and have interest in Hashing.
It would be very helpful if someone could help me with a simple MurmurHash3 Flowchart.
Since I'm a newbie and still can't add any comment there, I also don't know how to contact Ian Boyd either, I'm trying to ask it here..
update
I made my own MurmurHash3 flowchart.
Will upload it later
I'm sorry for my noobness and bad in English. Thank you
I know I am reply late, but it may help any one else...
Murmur hashing is a non cryptographic hash function
which is used for hash based look-ups , it uses 3 basic operations as a whole Multiply, Rotate and XOR. It uses multiple constants which are just there to make it good hash function by passing 2 basic tests.
Avalanche Test
Chi-Squared Test
You can watch this video, which I made, for the detail explanation of Murmur Hashing.
Related
does anyone knows a link to examples of solvable 3SAT problems, with also the solution to the problem?
Thanks
You can construct a trivial solveable 3Sat instance, which is solveable in polynomial time. There are several ways to construct trivial solveable 3Sat problems:
Use each variable exactly one times -> each variable setting is a solution
Don't use negations -> each variable is set to true is a solution
...
I don't know a non trivial 3Sat example, which is big and solveable. Ones a year the Sat Competition is held. You can look into the benchmarks, whether there is a 3Sat benchmark.
this is what I did:
download 3 SAT examples, for for example this site:
https://www.cs.ubc.ca/~hoos/SATLIB/benchm.html
in the download items, UF means it is satisfiable, uuf it means it is unsatisfiable.
Then I add these examples to https://msoos.github.io/cryptominisat_web/, which is a version of MiniSAT (SAT solver) in the browser.
Click the play button, and MiniSAT calculates the solution.
For reference I only know python so that's what I've been working with.
I've recently been looking into making my own hashing algorithm to further my understanding on how they work, I'm not looking into creating the most cryptographically secure hashing algorithm, just something that is a bit more secure than validating passwds in plain-text.(in other words I don't care if this algorithm has copious amounts of collisions.
From what I understand about hash functions is that they use ???? to obfuscate the input password. Where I'm getting caught up is how the function takes a user input, like "password1" and translates that into numbers the system can work with, then, what exact methods do they use to obfuscate them?
Apologies if this is a stupid question but I cant find any material on this that isn't way beyond my understanding or basic enough where they gloss over what happens inside the hash algorithm.
I'm looking for a tool to convert a SBML model into a Matlab function. I've tried SBMLTranslate() function from libSBML but this returns a Matlab struct, not a function. Does anybody know if such tool exists? Thanks
There are at least three efforts in this direction:
Frank Bergmann offers an online service for SBML translation where you can upload an SBML file and it will generate a MATLAB file. The comments at the top of the generated MATLAB file explain how to use the results. The C++ source code is available on SourceForge.
Bergmann's code referenced above was used by Stanley Gu to create sbml2matlab, a Windows standalone program. Off-hand, I don't know whether Gu's version changed or enhanced the algorithm used by the Bergmann version, but it seems likely. (Note: Gu now works at Google and does not maintain this code anymore, as far as I know.)
The Systems Biology Format Converter (SBFC) is a framework written principally by Nicolas Rodriguez; it includes a collection of converters, one of which is an SBML-to-MATLAB converter. This converter is written in Java.
I have not compared the results of the translators myself yet, so cannot speak to the differences or quality of output. If you try them and have any feedback to relate, please let the authors know. Knowing what has or hasn't worked for real users will help improve things in the future.
A final caveat is that all of these have been research projects, so make sure to set your expectations accordingly. (This is not a criticism of the authors; the authors are very good – I know most of them personally – but the reality of academic development work is that we all lack the time and resources to make these systems comprehensive, hardened, polished, and documented to the degree that we wish we could.)
Does anyone know of any examples of code written in prolog to implement a DSL to generate perl code?
DCGs might be an excellent choice!
I have used a similar approach for generation of UML class diagrams (really, graphviz code for such diagrams) from simple English sentences (shameless-plug: paper here). It should be possible to do something similar with generation of Perl code instead.
In the paper above, we use a constraint store (CHR) as intermediate representation which allows some extra reasoning power. Alternatively you can build a representation as an output feature/argument of the DCG.
Note that DCGs can be useful both for the parsing of your sentences and the generation of your Perl code.
Well, not exactly what you are asking for, but maybe you can use AI::Prolog for what you are looking for. That way you may be able to use Perl and generate the Perl code you want.
I'm not sure why you would want to do that?
Perl is a very expressive language, I'm not sure why you'd want to try to generate Perl code from Prolog; in order to make it useful, you'd be getting closer and closer to Perl in your "DSL", by which point you'd be better off just writing some Perl, surely?
I think you need to expand this question a bit to cover what you're trying to achieve in a little more detail.
SWI-Prolog library(http/html_write) library builds on DCG a DSL for page layout.
It shows a well tought model for integrating Prolog and HTML, but doesn't attempt to cover the entire problem. The 'residual logic' on the client side remains underspecified, but this is reasonable, being oriented on practical issues 'reporting' from RDF.
Thus the 'small detail' client interaction logic is handled in a 'black box' fashion, and such demanded to YUI components in the published application (the award winner Cliopatria).
The library it's extensible, but being very detailed, I guess for your task you should eventually reuse just the ideas behind.
I was asked at the coding theory course to implement a compression hash function and an iteration technique of my choice.
What is supposed to mean "an iteration technique" ?
I choosed SHA-1 for the hash func.
P.S. Sorry, I'm not a native English speaker, that's why I'm asking such an ambiguous question.
It probably refers to the creation of an iterative hash function using a compression hash function as mentioned here and here.