I might be missing something but why does temperature 0 imply determinism? Neural nets don’t work with real numbers, they work with floating points numbers so despitetemperature 0 implying an argmax there’s no reason there arent justmultiple maxima. AFAICT GPT3 uses half precision floating point numbers so there’s quite a lot of space for collisions.
It’s extremely unlikely that two biggest logits have the exact same value — there are still a lot of floating point numbers even with float16!!
The reason there’s no determinism is because of a combination of lower precision and nondeterministic reduce operations (eg sums). For example, the order in which terms are accumulated can vary with the batch size, which, for models as large as GPT3, can make the logits vary by up to 1%.
Oh interesting didn’t realise there was so much nondeterminism for sums on GPUs
I guess I thought that there’s only 65k float 16s and the two highest ones are going to be chosen from a much smaller range from that 65k just because they have to be bigger than everything else.
I might be missing something but why does temperature 0 imply determinism? Neural nets don’t work with real numbers, they work with floating points numbers so despitetemperature 0 implying an argmax there’s no reason there arent justmultiple maxima. AFAICT GPT3 uses half precision floating point numbers so there’s quite a lot of space for collisions.
It’s extremely unlikely that two biggest logits have the exact same value — there are still a lot of floating point numbers even with float16!!
The reason there’s no determinism is because of a combination of lower precision and nondeterministic reduce operations (eg sums). For example, the order in which terms are accumulated can vary with the batch size, which, for models as large as GPT3, can make the logits vary by up to 1%.
Oh interesting didn’t realise there was so much nondeterminism for sums on GPUs
I guess I thought that there’s only 65k float 16s and the two highest ones are going to be chosen from a much smaller range from that 65k just because they have to be bigger than everything else.