Solved

# Parallel.For Loop Q?

Posted on 2011-03-24
758 Views
How can I use Step in a Parallel.For loop?

For Instance, I can do this:
For i As Integer = 0 To 100 Step 10
'Do Something
Next

But this:
Parallel.For(0, 100 Step 10, Function(i)
'Do Something
End Function)

0
Question by:kevp75
• 5
• 4
• 2

LVL 23

Assisted Solution

wdosanjos earned 150 total points
ID: 35209034
AFAIK, there is no way to set the Step on a Parallel.For (it is always 1).  You can work around this limitation by calculating your index as below:

``````Parallel.For(0, 10, Function(i)
Dim index As Integer = i * 10
'Do Something
End Function)
``````
0

LVL 27

Expert Comment

ID: 35209077
0

LVL 25

Author Comment

ID: 35209183
Arun, i don't understand how it applies to my need
0

LVL 25

Author Comment

ID: 35215073
hello?
0

LVL 27

Accepted Solution

nmarun earned 350 total points
ID: 35220467
Have a look here: http://www.lovethedot.net/2009/02/parallelfor-deeper-dive-parallel.html - tells you there's no way to give a step-size for the Parallel.For method.

Arun
0

LVL 25

Author Comment

ID: 35221874
it doesn't say anywhere in that article that a step size cannot be used.
0

LVL 27

Expert Comment

ID: 35221998
The article says:

you wouldn’t be able to modify the iterator inside the loop as you can in for

Arun
0

LVL 25

Author Comment

ID: 35243486
ah
0

LVL 23

Expert Comment

ID: 35243671
BTW, I provided the answer way before the accepted solution.
0

LVL 27

Expert Comment

ID: 35270503
wdosanjos, Although you did answer the question before, I think your 'AFAIK' (your first post) intimated the author that you were not sure and that there might be a way of doing this. But when I provided a documented way of telling this, the author was convinced. So I'm ok with a half-split of points on this. Sorry, this was an oversight by me, should have seen this before.

kevp75, Please split the points between wdosanjos and I.

Arun
0

LVL 25

Author Closing Comment

ID: 35278971
tank you
0

## Featured Post

### Suggested Solutions

Calculating holidays and working days is a function that is often needed yet it is not one found within the Framework. This article presents one approach to building a working-day calculator for use in .NET.
International Data Corporation (IDC) prognosticates that before the current the year gets over disbursing on IT framework products to be sent in cloud environs will be \$37.1B.
Access reports are powerful and flexible. Learn how to create a query and then a grouped report using the wizard. Modify the report design after the wizard is done to make it look better. There will be another video to explain how to put the final p…
This tutorial demonstrates a quick way of adding group price to multiple Magento products.