Visible to Intel only — GUID: GUID-3BDAF6D4-93F2-465F-B966-9E43F0443A8E
Visible to Intel only — GUID: GUID-3BDAF6D4-93F2-465F-B966-9E43F0443A8E
Using Floating Point for Calculations
Intel® Graphics device is much faster for floating-point add, sub, mul and so on in compare to the int type.
For example, consider the following code that performs calculations in type int4:
__kernel void amp (__constant uchar4* src, __global uchar4* dst)
…
uint4 tempSrc = convert_uint4(src[offset]);//Load one RGBA8 pixel
//some processing
uint4 value = (tempSrc.z + tempSrc.y + tempSrc.x);
uint4 tempDst = value + (tempSrc - value) * nSaturation;
//store
dst[offset] = convert_uchar4(tempDst);
}
Below is its float4 equivalent:
__kernel void amp (__constant uchar4* src, __global uchar4* dst)
…
uint4 tempSrc = convert_uint4(src[offset]);//Load one RGBA8 pixel
//some processing
float4 value = (tempSrc.z + tempSrc.y + tempSrc.x);
float4 tempDst = mad(tempSrc – value, fSaturation, value);
//store
dst[offset] = convert_uchar4(tempDst);
}
Intel® Advanced Vector Extensions (Intel® AVX) support (if available) accelerates floating-point calculations on the modern CPUs, so floating-point data type is preferable for the CPU OpenCL device as well.