# Caculated time One Point Multiplication with double and method

I am using double and add method for point multiplication in affine coordinates. How we compute 1PM in double and method?

Di Wang said one point multiplication consists of repeated addition and doubling operations, so the calculated time of point multiplication

#ADD*1ADD + #DBL*1DBL


more less equals 1PM. But when I calculate with the formula show different result:

#ADD*1ADD + #DBL*1DBL = 127#ADD*2ms + 256#DBL*3ms = 766ms


Actual 1PM = 421ms.

This is a huge difference. Can anyone explain this difference?

Double and add algorithm requires log2(n) iterations of point doubling and addition to compute the full-point multiplication.

So I think that: $2^y = n$ where $y$ is number point addition or doubling

Edited:

• I've formatted your question. Please do not use '#' for formulas but use Latex (or ask for help). I'm not sure about your equations to I've turned them into code fragments. Please edit your question again to clear things up. What do you mean with ADD*ADD? Please reread your question before hitting the post button. – Maarten Bodewes Feb 10 '16 at 9:02
• @MaartenBodewes #ADD is supposed to be the number of additions. – CodesInChaos Feb 10 '16 at 10:20