Distribution of floating-point operations in scientific computing
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I am looking for data about the distribution of floating-point operations - what percentage are additions/subtractions, what percentage are multiplications, etc. My Google-fu isn't working today, so I would appreciate any pointers.
If you have an important point to make, don't try to be subtle or clever. Use a pile driver. Hit the point once. Then come back and hit it again. Then hit it a third time - a tremendous whack. --Winston Churchill
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I am looking for data about the distribution of floating-point operations - what percentage are additions/subtractions, what percentage are multiplications, etc. My Google-fu isn't working today, so I would appreciate any pointers.
If you have an important point to make, don't try to be subtle or clever. Use a pile driver. Hit the point once. Then come back and hit it again. Then hit it a third time - a tremendous whack. --Winston Churchill
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I am looking for data about the distribution of floating-point operations - what percentage are additions/subtractions, what percentage are multiplications, etc. My Google-fu isn't working today, so I would appreciate any pointers.
If you have an important point to make, don't try to be subtle or clever. Use a pile driver. Hit the point once. Then come back and hit it again. Then hit it a third time - a tremendous whack. --Winston Churchill
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I am looking for data about the distribution of floating-point operations - what percentage are additions/subtractions, what percentage are multiplications, etc. My Google-fu isn't working today, so I would appreciate any pointers.
If you have an important point to make, don't try to be subtle or clever. Use a pile driver. Hit the point once. Then come back and hit it again. Then hit it a third time - a tremendous whack. --Winston Churchill
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42 The time unit is arbitrary.
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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I'd need crack to want to read it!
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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I'd need crack to want to read it!
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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I am looking for data about the distribution of floating-point operations - what percentage are additions/subtractions, what percentage are multiplications, etc. My Google-fu isn't working today, so I would appreciate any pointers.
If you have an important point to make, don't try to be subtle or clever. Use a pile driver. Hit the point once. Then come back and hit it again. Then hit it a third time - a tremendous whack. --Winston Churchill
Are you looking for exact values (measured values) or statistics? For statistical purposes it is 25% each :-)
Skipper: We'll fix it. Alex: Fix it? How you gonna fix this? Skipper: Grit, spit and a whole lotta duct tape.
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I am looking for data about the distribution of floating-point operations - what percentage are additions/subtractions, what percentage are multiplications, etc. My Google-fu isn't working today, so I would appreciate any pointers.
If you have an important point to make, don't try to be subtle or clever. Use a pile driver. Hit the point once. Then come back and hit it again. Then hit it a third time - a tremendous whack. --Winston Churchill
This can't be answered since FMA (Multiply–accumulate operation - Wikipedia[^]) has been introduced because it would require to know the distribution of zero FMA arguments.
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I remember reading that someone had performed such an analysis, but I can't find any pointers to it. The idea was that additions/subtractions are more common than multiplications, which in turn are much more common than divisions/square root. This implies that optimizing the less common operations is likely to give a lower return than optimizing the more common operations. As I said, my Google-fu is non-functional today. :(
If you have an important point to make, don't try to be subtle or clever. Use a pile driver. Hit the point once. Then come back and hit it again. Then hit it a third time - a tremendous whack. --Winston Churchill
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Are you looking for exact values (measured values) or statistics? For statistical purposes it is 25% each :-)
Skipper: We'll fix it. Alex: Fix it? How you gonna fix this? Skipper: Grit, spit and a whole lotta duct tape.
Kornfeld Eliyahu Peter wrote:
For statistical purposes it is 25% each :)
Actually, it isn't. A review of floating-point programs that I have written shows that addition/subtraction is more common than multiplication, and these are much more common than division/square root. I am writing various floating-point libraries, and would like this information so I can know where to spend my optimization time.
If you have an important point to make, don't try to be subtle or clever. Use a pile driver. Hit the point once. Then come back and hit it again. Then hit it a third time - a tremendous whack. --Winston Churchill
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I am looking for data about the distribution of floating-point operations - what percentage are additions/subtractions, what percentage are multiplications, etc. My Google-fu isn't working today, so I would appreciate any pointers.
If you have an important point to make, don't try to be subtle or clever. Use a pile driver. Hit the point once. Then come back and hit it again. Then hit it a third time - a tremendous whack. --Winston Churchill
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Looks to me that every body is wrong. There are clearly more zeros than ones. Each byte is packed with leading zeros. The ones are big-time losers. QED. :laugh:
Wrong thread?
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Wrong thread?
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I am looking for data about the distribution of floating-point operations - what percentage are additions/subtractions, what percentage are multiplications, etc. My Google-fu isn't working today, so I would appreciate any pointers.
If you have an important point to make, don't try to be subtle or clever. Use a pile driver. Hit the point once. Then come back and hit it again. Then hit it a third time - a tremendous whack. --Winston Churchill
What for ?
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What for ?
I'm writing a floating-point package in C++ that provides: 1. A full implementation of the binary part of the IEEE-754-2008 Standard for Floating-Point Arithmetic (single-, double- and quad-precision) 2. Implementation of higher-precision formats, compatible with the Standard (up to binary1024). I have a basic implementation written using the "standard" algorithms, and would like some idea of where to invest time on improvements. Obviously, spending a lot of time on an operation that is rarely executed is not the best use of my time... :)
If you have an important point to make, don't try to be subtle or clever. Use a pile driver. Hit the point once. Then come back and hit it again. Then hit it a third time - a tremendous whack. --Winston Churchill
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Woops! Yes, it should be the thread below. :-O You will understand my difficulty when you see my next thread. :laugh:
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I'm writing a floating-point package in C++ that provides: 1. A full implementation of the binary part of the IEEE-754-2008 Standard for Floating-Point Arithmetic (single-, double- and quad-precision) 2. Implementation of higher-precision formats, compatible with the Standard (up to binary1024). I have a basic implementation written using the "standard" algorithms, and would like some idea of where to invest time on improvements. Obviously, spending a lot of time on an operation that is rarely executed is not the best use of my time... :)
If you have an important point to make, don't try to be subtle or clever. Use a pile driver. Hit the point once. Then come back and hit it again. Then hit it a third time - a tremendous whack. --Winston Churchill
Daniel Pfeffer wrote:
I'm writing a floating-point package in C++
That was not clear from your original question. So I will dig in here: I would not think about that. All basic operations will be used often (more or less) and should be therefore optimised as far as possible. Because division is the slowest operation it might be the first candidate even used probably less than the other operations. When a calculation uses divisions, a better implementation would probably reduce the overall calculation time by a greater factor than without division optimsation but with addition and multiplication optimisation.
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Daniel Pfeffer wrote:
I'm writing a floating-point package in C++
That was not clear from your original question. So I will dig in here: I would not think about that. All basic operations will be used often (more or less) and should be therefore optimised as far as possible. Because division is the slowest operation it might be the first candidate even used probably less than the other operations. When a calculation uses divisions, a better implementation would probably reduce the overall calculation time by a greater factor than without division optimsation but with addition and multiplication optimisation.
OK, that makes sense. Thanks.
If you have an important point to make, don't try to be subtle or clever. Use a pile driver. Hit the point once. Then come back and hit it again. Then hit it a third time - a tremendous whack. --Winston Churchill
