[RESOLVED] I'm Looking For A List Of Most Efficient Algorithms

[Honduras 2811]

I never thought I would need one because I could usually find out with an Internet search, but VB .NET is starting to show up more and more in the searches, and VB6 less and less.

Does anyone have, or know where I can find, a list of what algorithms to use in what situations?

A not very good example is using Longs instead of Integers. From a memory standpoint, Integers seem to make sense, but I've been told that Longs process faster.

What I'm working on is converting some of the tables in 'Machinery's Handbook' to VB 6 applications. They aren't very complicated, so I thought I might try and make the code as efficient as possible.

[Schmidt]

Did you ever tried the '-' Operator in Google?

Your problem-description is too common - please point out a specific algorithm -
and you will get help (or at least a matching google-search-string )

Olaf

[jpbro]

It sounds like you might mean best coding practices for efficiency instead of algorithms? If so this might be some interesting reading: http://www.aivosto.com/resources.html

[dilettante]

It sounds like you might mean best coding practices for efficiency instead of algorithms?

I agree. The question is clearly asking about implementation decisions rather than algorithms.

E.g. you might find the fastest sorting algorithm known to man (for your specific situation, since "fastest" like "best" is a very situational thing). But a poor implementation might make it slower than the worst known algorithm well implemented.

People need to learn what words mean before trying to use them. With the Internet there is hardly any excuse anymore.

[szlamany]

Does this link give you any info that might help?

http://msdn.microsoft.com/en-us/libr...(v=vs.60).aspx

[Honduras 2811]

I agree. The question is clearly asking about implementation decisions rather than algorithms.

E.g. you might find the fastest sorting algorithm known to man (for your specific situation, since "fastest" like "best" is a very situational thing). But a poor implementation might make it slower than the worst known algorithm well implemented.

People need to learn what words mean before trying to use them. With the Internet there is hardly any excuse anymore.

dilettante, I don't know why you get such a kick out of irritating me.

Definition of algoritm: problem-solving computer program: a logical sequence of steps for solving a problem, often written out as a flow chart, that can be translated into a computer program.

That is exactly what I am looking for.

EDIT: The MSDN link is old news. The Aviosto link has a few interesting articles, but it's not what I'm looking for.

I'm also not looking for help with only one algorithm.

There used to be a website that was called ExtremeVB, I think, and it had a whole indexed section on algorithm optimization. If it is even the same site, it is all VB .NET now.

As I said, the example I gave was very bad. How about this? Things like when to use bit manipulation instead of VB's built in math functions.

[Schmidt]

Definition of algoritm: problem-solving computer program: a logical sequence of steps for solving a problem, often written out as a flow chart, that can be translated into a computer program.

That is exactly what I am looking for.

No, I don't think so... because you write further below:

There used to be a website that was called ExtremeVB, I think, and it had a whole indexed section on algorithm optimization. If it is even the same site, it is all VB .NET now.
... Things like when to use bit manipulation instead of VB's built in math functions.

So, that sounds more like you're looking for general-code-optimizations
(what to do, or what to avoid across a whole range of algorithms, meaning
performance-related implementation-tricks, which are useful to know in VB6).

And from the top of my head, there's really only a few things, which can be sumed up this way:
- VB6 has a built-in C-Compiler, which generates native code, that runs about factor 5-10 faster than IDE-PCode
- The native compiler will find around factor 2-3 in addition, when *all* extended "native options" are checked.
- For the native compiler to give the above speed increase, you will have to work directly on "native types"
- the above meaning: VBs standard-types (or UDTs which consist of only those simple types) and arrays of those types
- avoid Objects and their method-calls in high-frequent inner-loops (same goes for normal function-calls in heavy loops)
- to handle longer String-content, avoid working directly on the String-Type (with Left$ or Mid$),
. (use ByteArrays, or even better: SafeArray-mapped 16bit-Int-Arrays in heavy parsing-loops
- in math-routines the VB-Double (on modern CPUs) is the faster type (compared with a Single)
- well, Integer-math is still fast - but floating-point-math is not much slower these days
- use LUT-Arrays (Look-Up-Tables) - to cache (repeatedly occuring) values (pre-calculated) and access them with an "index as parameter"
- avoid an active Errorhandler in fast routines
- at least switch it off with On Error Goto 0, when you reach the fast inner loop in a function (assuming the inner-loop was well-tested before).

That's it already - many of the often occuring BitShifting-stuff in some Base-Algos can be done
either per simple addition (left shift by one bit using IntValue+IntValue) or by * or \ ... but alternatively also using LUTs.

The concrete appliance of the above, then depending on the type of algorithm of course.

Only thing left to say is, that all those tips only play a role in high-frequented loops (with loop-counts
in the tens of thousands or higher) - it doesn't matter at all, if you used a Variant-Type - or normal
VB-String-functions - or even the often frowned upon Split("1,2,3",",")(0) sequences, as long as you
use them only in normal Click- or GUI-Events which come along only "any few seconds" due to
occasional UserInteraction - a better look can be taken again, when you have constantly running Timers
(with short intervals below 100) ... but in my experience there's really only a few "hot-spots", where
extensive optimizations will make sense - but those spots exist of course - they are usually relatively
easy to identify (e.g. when you time larger blocks - and stuff gets commented out and later back-in) ...
as said, this will be mostly routines, where some higher loop-counts were applied.

HTH

Olaf

[Arnoutdv]

There used to be a website that was called ExtremeVB, I think, and it had a whole indexed section on algorithm optimization. If it is even the same site, it is all VB .NET now

Do you mean vbSpeed:
http://www.xbeat.net/vbspeed/

[Honduras 2811]

Do you mean vbSpeed:
http://www.xbeat.net/vbspeed/

Purrrfect. That's the one. TYVM.