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[spectral]

Hi,

I have a compilation error :

"expression must have arithmetic, enum, or pointer type"

   if (Li != (clSpectrum)(0.f))

      ^

But I don't know why ! The OpenCL spec tell that we can do this... even that we can do "Li != 0.f" !

Please, can you advice ?

float3 Li = ... if (Li != (float3)(0.f))

[LeeHowes]

clSpectrum isn't typedefed to a float3 or scalar, I imagine? It's a struct of some sort?

I would guess that the problem is that OpenCL doesn't define comparison on arbitrary structs. float3 has the comparison operators overloaded on it, and unfortunately as OpenCL C has pretensions of being C rather than C++ you cannot overload other operators on structures.

That's my guess. I've never actually checked to see if struct comparisons work, though.

[himanshu_gautam]

I tried the following kernel:

__kernel void test(global float *A, global float *B) {
   int pos = get_global_id(0);
   float4 LI = {0.1f,0.4f,87.87f,0.0f};
   float4 LI1 = {0.0f,0.4f,0.8f,0.0f};
 if(LI != LI1)
 {
 
 }
}

and got the same error.

Thanks for repeating the issue. It has been reported to concerned people.

[himanshu_gautam]

Okay. ITs nothing wrong with the implementation. actually you cannot put vectors directly in a if condition. The above comparison will result a vector but if takes a scalar. Do this instead and it works

if(all(L1 != L))

{}

[spectral]

Oups, sorry, I just have this

#define clSpectrum float3

So, it is a float3 and not a custom typedef !

What I want is to do this :

if (Li.x != 0 || Li.y != 0 || Li.z != 0) ...

why I cannot write this as if (Li != 0) ??? The specification tell that we can do this !!!

[himanshu_gautam]

Li != 0 is valid. But it appears to be returning a vector type which "if" cannot handle.

[gopal_hc]

Hi,

I also got the same error while compiling following code:

uint8 i = 0;

for(i = 0; i < 8; i++)

{

    //body of loop

}

/tmp/OCLdm84ZS.cl", line 623: error: expression must have arithmetic, enum,

          or pointer type

          for(i = 0; i < 8; i++)

I fixed the error by changing uint8 to int. The reason i understood as explained by "Lee Howes"  is that  OpenCL does not define comparision on arbitrary structure. Correct me if I understood wrong !!!