Confuse about LDS sample

Discussion created by riza.guntur on Aug 14, 2009
Latest reply on Aug 16, 2009 by riza.guntur

Up until now I still don't get it.

Does instance() work like usual without conflicting with instanceInGroup()?

If we have streams bigger than GROUP_SIZE, will it have different lds? Or can't access other lds?

Why Stream of type VectorType/float4 can read from array of ScalarType/float?

What is the range of instanceInGroup().x there? Is it the same of GROUP_SIZE?

How do I know my thread is in different group from other threads? 


What it means:


//Reading from last Thread


item = 4 * (GROUP_SIZE - 1 - instanceInGroup().x )+ 0;

How come it reads from last thread?

If instanceInGroup().x returns 0 to 63 then 4*(64-1- anywhere from 0 to 63) + 0 = reverse.... really?



The shared VectorType lds[256]; is used only in offset 0 right? If so, the algorithm can work with some modification and run with only 64 lds elements right?

So the algorithm means reverse summing column of a and b then put in c... If my thoughts are correct...


Can I build 2d/3d LDS? How big its maximum?

In lds sample, one group is one row right?

Can I specify 2d group in 3d stream?

Sorry for redundant questions.