Currently, Boost only implements the random_device class for Linux (maybe *nix) systems. Does anyone know of existing implementations for other OS-es? Ideally, these implementations would be open-source. If none exist, how should I go about implementing a non-deterministic RNG for Windows as well as Mac OS X? Do API calls exist in ei...
So I've had at least two professors mention that backtracking makes an algorithm non-deterministic without giving too much explanation into why that is. I think I understand how this happens, but I have trouble putting it into words. Could somebody give me a concise explanation of the reason for this? ...
If you set up a table's column to be a computed column whose Formula calls a Function, it becomes a pain to change that underlying Function. With every change, you have to find every single column whose Formula that references the Function, remove the reference, save the Table, alter the Function, add everything back, and save again. Ev...
I have the following function: SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO ALTER FUNCTION [dbo].[IP4toBIGINT]( @ip4 varchar(15) ) RETURNS bigint WITH SCHEMABINDING AS BEGIN -- oc3 oc2 oc1 oc0 -- 255.255.255.255 -- Declared as BIGINTs to avoid overflows when multiplying later on DECLARE @oct0 bigint, @oct1 b...
According to MSDN SQL BOL (Books Online) page on Deterministic and Nondeterministic Functions, non-deterministic functions can be used "in a deterministic manner" The following functions are not always deterministic, but can be used in indexed views or indexes on computed columns when they are specified in a deterministic manner. ...
Situation: condition check in C++ or C# with many criteria: if (condition1 && condition2 && condition3) { // Do something } I've always believed the sequence in which these checks are performed is not guaranteed. So it is not necessarily first condition1 then condition2 and only then condition3. I learned it in my times with C++. ...
I have made a quite few genetic algorithms; they work (they find a reasonable solution quickly). But I have now discovered TDD. Is there a way to write a genetic algorithm (which relies heavily on random numbers) in a TDD way? To pose the question more generally, How do you test a non-deterministic method/function. Here is what I have ...
Is it possible to implement McCarthy's amb-operator for non-deterministic choice in C#? Apparently .NET lacks continuation support but yield return could be useful. Would this be possible in other static .NET-languages like F#? ...
The problem is that when I run the code below, on a single core, sometimes it runs correctly,and sometimes I get segmentation fault. Probably this problem will occure more frequently on a multi-core machine. I need to know where this non-determinism is introduces in my program and how can I resolve it.thanks. int numThreads = 4; class...
I know in Prolog you can do something like someFunction(List) :- someOtherFunction(X, List) doSomethingWith(X) % and so on This will not iterate over every element in List; instead, it will branch off into different "machines" (by using multiple threads, backtracking on a single thread, creating parallel universes or what...
After a bit of searching and reading the documentation, it's clear that you can write user defined functions in SQL Server that are marked as either deterministic or nondeterministic depending on which built-infunctions are used within the body. RAND() is listed under the nondeterministic functions (see msdn article). So why can't I use...
I have the following user-defined function: create function [dbo].[FullNameLastFirst] ( @IsPerson bit, @LastName nvarchar(100), @FirstName nvarchar(100) ) returns nvarchar(201) as begin declare @Result nvarchar(201) set @Result = (case when @IsPerson = 0 then @LastName else case when @FirstName = '' then @LastName el...
I have some code that I have inherited which is part of a class for iterating, accessing the directory content and uses boost::filesystem::path. The code reads in part: struct directory_iterator_impl { private: void skip_dots(const path& p, const char* who) { static const std::string d("."); static const std::string dd(".."...
I know that I can not compare two floating point or double numbers for absolute equality on C++/C. If for some reason, I write a if condition which uses the absolute equality, is it guaranteed that the if condition will return the same result on different runs of the program for same data? Or it is purely non-deterministic and the result...
Normally it is said that multi threaded programs are non-deterministic, meaning that if it crashes it will be next to impossible to recreate the error that caused the condition. One doesn't ever really know what thread is going to run next, and when it will be preempted again. This off course has to do with the OS Thread scheduling alg...