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(Free42) roundoff for complex SQRT
05-11-2018, 09:06 AM
Post: #20
RE: (Free42) roundoff for complex SQRT
(04-04-2018 03:03 PM)Claudio L. Wrote:  
(04-04-2018 10:24 AM)Dan Wrote:  I used the "Friden" algorithm for square root on the AriCalculator, and sqrt(z) = sqrt(.5(a+sqrt(a^2+b^2)) )+ sqrt(0.5(-a+sqrt(a^2+b^2))). This gives exact results for 8i and other z I tried for which Re(z) = 0 and Im(z)/2 is a perfect square

This is what I used on newRPL too, but I'm probably going to change it to what Werner showed above for the 48, it saves one square root, so it's roughly 30% faster.

Actually on my system it's slower (2 - 3 times), probably because I'm using a shift and add algorithm for division, so division is much slower than square root.
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RE: (Free42) roundoff for complex SQRT - Dan - 05-11-2018 09:06 AM

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