Mathy Question: decimal exponents with the cordic method
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Hi everyone! I'm trying to figure out how calculators calculate x^y where y is a non-integer. I've learned that they use the cordic method, but does anyone have any idea how this method works on exponents? I've seen examples with square roots and trig functions, but no exponential. A good link or simple explanation would be great if anyone knows of one. Thanks! If you have a problem with my spelling, just remember that's not my fault. I (as well as everyone else who learned to spell after 1976) blame it on Robert A. Kolpek for U.S. Patent 4,136,395.
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Hi everyone! I'm trying to figure out how calculators calculate x^y where y is a non-integer. I've learned that they use the cordic method, but does anyone have any idea how this method works on exponents? I've seen examples with square roots and trig functions, but no exponential. A good link or simple explanation would be great if anyone knows of one. Thanks! If you have a problem with my spelling, just remember that's not my fault. I (as well as everyone else who learned to spell after 1976) blame it on Robert A. Kolpek for U.S. Patent 4,136,395.
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They use the identity x^y = e ^ (y ln x) ln(x) and and e^x can be approximated by a infinite sum.
we are here to help each other get through this thing, whatever it is Vonnegut jr.
sighist || Agile Programming | doxygenpeterchen wrote: ln(x) and and e^x can be approximated by a infinite sum. Or... you can utilize your FPU to do the calculations. :-D Anyhow, it's a really cool math trick! :cool: -- Arigato gozaimashita!
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peterchen wrote: ln(x) and and e^x can be approximated by a infinite sum. Or... you can utilize your FPU to do the calculations. :-D Anyhow, it's a really cool math trick! :cool: -- Arigato gozaimashita!
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Jörgen Sigvardsson wrote: Or... you can utilize your FPU to do the calculations. ...which does the same :rolleyes:
we are here to help each other get through this thing, whatever it is Vonnegut jr.
sighist || Agile Programming | doxygenI figured as much. But I view the FPU as a black box, so to me it's as if there's a mathematician inside who calculates an exact value which it rounds. I wonder how they squeezed the mathematician into the FPU, and isn't that illegal? :~ :-D -- Arigato gozaimashita!
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I figured as much. But I view the FPU as a black box, so to me it's as if there's a mathematician inside who calculates an exact value which it rounds. I wonder how they squeezed the mathematician into the FPU, and isn't that illegal? :~ :-D -- Arigato gozaimashita!
Jörgen Sigvardsson wrote: I wonder how they squeezed the mathematician into the FPU, and isn't that illegal? Martial arts techniques perhaps ? :) "One of the Georges," said Psmith, "I forget which, once said that a certain number of hours' sleep a day--I cannot recall for the moment how many--made a man something, which for the time being has slipped my memory."
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Jörgen Sigvardsson wrote: I wonder how they squeezed the mathematician into the FPU, and isn't that illegal? Martial arts techniques perhaps ? :) "One of the Georges," said Psmith, "I forget which, once said that a certain number of hours' sleep a day--I cannot recall for the moment how many--made a man something, which for the time being has slipped my memory."
I think Marshalling Arts would be more handy for squeezing someone into an FPU. :-D -- Arigato gozaimashita!
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I think Marshalling Arts would be more handy for squeezing someone into an FPU. :-D -- Arigato gozaimashita!