Array performance

[Guest]

from using FxCop and reading MSDN i understand that i should not use properties to access arrays, i should use methods instead,
however when i try the code below the MSIL for method and property access is identical, bar a slight differenc in code size and stack size.
What is the correct way to access an array, given that i need to perform actions on sections of the array as well as individual elements. Do I just access it directly? (in my actual app the array is 2 dimensional, approx 64k elements)

sample code:-
Private _a(100) As Integer
Public Property a() As Integer()
Get
Return _a
End Get
Set(ByVal Value() As Integer)
_a = Value
End Set
End Property
Public Function GetA() As Integer()
Return _a
End Function
Public Function SetA(ByVal x() As Integer) As Integer()
_a = x
End Function

 

[Cor Ligthert]

Hi guy,

To test those things you can just set it in a loop than you know the
difference, not with a single

As timer you can take
dim start as integer = environment.tickcount
your process
dim endtime as integer = environment.tickcount - start

Cor

from using FxCop and reading MSDN i understand that i should not use

properties to access arrays, i should use methods instead,

however when i try the code below the MSIL for method and property access

is identical, bar a slight differenc in code size and stack size.

What is the correct way to access an array, given that i need to perform

actions on sections of the array as well as individual elements. Do I just
access it directly? (in my actual app the array is 2 dimensional, approx
64k elements)

 

[Cor Ligthert]

Hi Guy,

What do you want to archieve in my opinon are you only passing a complete
array in all your samples, is that what you want to archieve?

So the time difference will me minimal between a method and a property

Cor

 

[Guest]

Hi Cor,
I need to perform processing on individual elements, for which a method would be fine, however I also need to do things like shifting blocks of elements up or down the array

Looks like I will just have to process the array directly

thanks

guy

 

[Cor Ligthert]

Hi Guy,

And why do you not use the standard arrays as the arraylist, hashtable,
sortedlist and more of those?

Cor

 

[Guest]

Hi Cor,
I actually need to process a 2D array approx(300,200)
so 60K elements , which are 4 byte strucures. In the course of a run a very rough estimate is 60K*60K*2 accesses ie 7,200,000,000
plus 30K array shifts so i need real performance!
there is virtuallt no other processing, just array crunching

guy

 

[Cor Ligthert]

Hi Guy,

Fixed or not Fixed?
With what I mean do you know in advance the size of it?

Cor

Hi Cor,
I actually need to process a 2D array approx(300,200)
so 60K elements , which are 4 byte strucures. In the course of a run a

very rough estimate is 60K*60K*2 accesses ie 7,200,000,000

 

[Cor Ligthert]

Hi Guy,

Go over to the language vb , I think that this needs a wider discussion than
only my opinion.

microsoft.public.dotnet.languages.vb

I agree it is not only language, however there you get more opinions.

(That is not that I will nog give my idea about this in that newsgroup,
however I think it is good to have in this huge array more opinions.)

Cor