Large errors using Intel OpenCL for CPUs about vkfft HOT 8 OPEN

Hello,

I have not yet managed to make this runtime work with my machine, but this issue resembles the low accuracy of sincos functions on Intel iGPUs. There is a fix for intel vendor id that it forces to precompute all twiddle factors in LUT there, my guess would be that vendor id is different in this case and the fix is not applied. Can you try setting config.useLUT = 1 and see if this fixes the issue?

Best regards,
Dmitrii

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That fixes it. Thank you so much!

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Great! However, I am not sure how to make this permanent as this is an issue of this particular specification.

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Would it make sense to enable useLUT by default whenever the platform vendor is Intel, whatever type of device it is?

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It already is on by default for vendor 0x8086 (Intel) though. Can you check the vendorID value for your device? The command is clGetDeviceInfo(device, CL_DEVICE_VENDOR_ID, sizeof(cl_int), &vendorID, 0);

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How very clever of them! :)

It's a little odd. They actually create two different platforms, each with a single device. The first one is called "Intel(R) FPGA Emulation Platform for OpenCL(TM)" and the device has vendor ID 0x1172. The second one is called "Intel(R) OpenCL" and the device has vendor ID 0x8086. The platform vendor for both of them is "Intel(R) Corporation".

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This vendor id apparently belongs to Altera Corporation. I guess I can add a special check for CL_PLATFORM_VENDOR to be Intel(R) Corporation as it is the common factor.

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Altera is now part of Intel. They bought it some years back.

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