Array performance

[guy]

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]

Re: Array performance

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.tic kcount
your process
dim endtime as integer = environment.tic kcount - start

Cor
[color=blue]
> from using FxCop and reading MSDN i understand that i should not use[/color]
properties to access arrays, i should use methods instead,[color=blue]
> however when i try the code below the MSIL for method and property access[/color]
is identical, bar a slight differenc in code size and stack size.[color=blue]
> What is the correct way to access an array, given that i need to perform[/color]
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)[color=blue]
>
> 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[/color]

[Cor Ligthert]

Re: Array performance

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

[guy]

Re: Array performance

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" wrote:
[color=blue]
> 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
>
>
>[/color]

[Cor Ligthert]

Re: Array performance

Hi Guy,

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

Cor

[guy]

Re: Array performance

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" wrote:
[color=blue]
> Hi Guy,
>
> And why do you not use the standard arrays as the arraylist, hashtable,
> sortedlist and more of those?
>
> Cor
>
>
>[/color]

[Cor Ligthert]

Re: Array performance

Hi Guy,

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

Cor

"guy" <guy@discussion s.microsoft.com > schreef in bericht
news:115643F8-4496-4A25-AA26-0EC0EE077564@mi crosoft.com...[color=blue]
> 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[/color]
very rough estimate is 60K*60K*2 accesses ie 7,200,000,000[color=blue]
> plus 30K array shifts so i need real performance!
> there is virtuallt no other processing, just array crunching
>
> guy
>
> "Cor Ligthert" wrote:
>[color=green]
> > Hi Guy,
> >
> > And why do you not use the standard arrays as the arraylist, hashtable,
> > sortedlist and more of those?
> >
> > Cor
> >
> >
> >[/color][/color]

[Cor Ligthert]

Re: Array performance

Hi Guy,

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

microsoft.publi c.dotnet.langua ges.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