Noel Carboni wrote:
Artificial intelligence trying to express itself? Cosmic rays? Kirlean messages from Beyond?
Sun spots...we've had a lot of solar flares lately...or mini black holes.
Have you tried the same test on two different raw conversions from one and the same file done on different days but with the same 64-bit binary?
Good point. One wonders whether maybe there are functions in there based on random numbers.
I've just tried it, since I saved PSD files when I was doing the comparisons yesterday. No dice - exact same results, different day.
Adobe needs to realize that it's NOT okay to produce inconsistent results, and that continuing to build on a foundation that does that WILL lead to trouble. This is a lot of decades of software engineering experience talking.
Differences are expected due to the use of floating-point math in the image processing, and 32-bit and 64-bit compilers result in different instructions being generated.
Thanks for your response, Eric.
I understand what you're saying, but a several bit difference in a 15 bit result is actually quite a lot to be attributed to math inaccuracy due to floating point operations. Even single precision 32 bit floating point operations should give you 24 bits of precision. A few bits at the end shouldn't add up to a visible difference, unless decisions are being made in the code based on results (e.g., if noise > threshold, do something).
Perhaps you don't use the Strict Floating Point Model, because if you did that should give you consistent results.
I've been through the decision of which floating point model to use in my own software, initially thinking that the Fast model would be better for speed (obviously), but as it turns out the repeatability of results with the Strict model is well worth the tiny bit of extra time it takes for the results to be predictable. You might want to reconsider using Strict, as I have, especially if these are not just round-off errors but decisions being made in the code based on floating point results. Looking around on the web, I see more folks than just I have made that specific choice.
Food for thought.
Thanks for testing this, Noel.