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In mathematics, for positive integers ''k'' and ''s'', a '''vectorial addition chain''' is a sequence ''V'' of ''k''-dimensional vectors of nonnegative integers ''v''<sub>''i''</sub> for −''k'' + 1 ≤ ''i'' ≤ ''s'' together with a sequence ''w'', | |||
such that | |||
:''v''<sub>-k+1</sub> = [1,0,0,,...0,0] | |||
:''v''<sub>-k+2</sub> = [0,1,0,,...0,0] | |||
::: . | |||
::: . | |||
: ''v''<sub>0</sub> = [0,0,0,,...0,1] | |||
: ''v''<sub>i</sub> =''v''<sub>j</sub>+''v''<sub>r</sub> for all 1≤i≤s with -k+1≤j,r≤i-1 | |||
: ''v''<sub>s</sub> = [''n''<sub>0</sub>,...,''n''<sub>k-1</sub>] | |||
: ''w'' = (''w''<sub>1</sub>,...''w''<sub>s</sub>), ''w''<sub>i</sub>=(j,r). | |||
For example, a vectorial addition chain for [22,18,3] is | |||
:''V''=([1,0,0],[0,1,0],[0,0,1],[1,1,0],[2,2,0],[4,4,0],[5,4,0],[10,8,0],[11,9,0],[11,9,1],[22,18,2],[22,18,3]) | |||
:''w''=((-2,-1),(1,1),(2,2),(-2,3),(4,4),(1,5),(0,6),(7,7),(0,8)) | |||
Vectorial addition chains are well suited to perform multi-[[exponentiation]].{{citation needed|date=April 2013}}{{vague|date=April 2013}} | |||
:'''Input''': Elements ''x''<sub>''0''</sub>,...,''x''<sub>''k-1''</sub> of an [[abelian group]] ''G'' and a vectorial addition chain of dimension ''k'' computing [''n''<sub>''0''</sub>,...,''n''<sub>''k-1''</sub>] | |||
:'''Output''':The element ''x''<sub>''0''</sub><sup>''n''<sub>''0''</sub></sup>...''x''<sub>''k-1''</sub><sup>''n''<sub>''r-1''</sub></sup> | |||
:# '''for''' ''i'' =''-k''+1 '''to''' 0 '''do''' ''y''<sub>''i''</sub> <math>\leftarrow</math> ''x''<sub>''i+k-1''</sub> | |||
:# '''for''' ''i'' = 1 '''to''' ''s'' '''do''' ''y''<sub>''i''</sub> <math>\leftarrow</math>''y''<sub>''j''</sub>×''y''<sub>''r''</sub> | |||
:#'''return''' ''y''<sub>''s''</sub> | |||
==Addition sequence== | |||
An '''addition sequence''' for the set of integer ''S ={n<sub>0</sub>, ...,n<sub>r-1</sub>}'' is an [[addition chain]] ''v'' that contains every element of ''S''. | |||
For example, an addition sequence computing | |||
:{47,117,343,499} | |||
is | |||
:(1,2,4,8,10,11,18,36,'''47''',55,91,109,'''117''',226,'''343''',434,489,'''499'''). | |||
It's possible to find addition sequence from vectorial addition chains and vice versa, so they are in a sense dual.<ref>Cohen, H., Frey, G. (editors): Handbook of elliptic and hyperelliptic curve cryptography. Discrete Math. Appl., Chapman & Hall/CRC (2006)</ref> | |||
==See also== | |||
*[[Addition chain]] | |||
*[[Addition-chain exponentiation]] | |||
*[[Exponentiation by squaring]] | |||
*[[Non-adjacent form]] | |||
==References== | |||
{{reflist}} | |||
[[Category:Addition chains]] | |||
Latest revision as of 19:44, 26 March 2013
In mathematics, for positive integers k and s, a vectorial addition chain is a sequence V of k-dimensional vectors of nonnegative integers vi for −k + 1 ≤ i ≤ s together with a sequence w, such that
- v-k+1 = [1,0,0,,...0,0]
- v-k+2 = [0,1,0,,...0,0]
- .
- .
- v0 = [0,0,0,,...0,1]
- vi =vj+vr for all 1≤i≤s with -k+1≤j,r≤i-1
- vs = [n0,...,nk-1]
- w = (w1,...ws), wi=(j,r).
For example, a vectorial addition chain for [22,18,3] is
- V=([1,0,0],[0,1,0],[0,0,1],[1,1,0],[2,2,0],[4,4,0],[5,4,0],[10,8,0],[11,9,0],[11,9,1],[22,18,2],[22,18,3])
- w=((-2,-1),(1,1),(2,2),(-2,3),(4,4),(1,5),(0,6),(7,7),(0,8))
Vectorial addition chains are well suited to perform multi-exponentiation.Potter or Ceramic Artist Truman Bedell from Rexton, has interests which include ceramics, best property developers in singapore developers in singapore and scrabble. Was especially enthused after visiting Alejandro de Humboldt National Park.Template:Vague
- Input: Elements x0,...,xk-1 of an abelian group G and a vectorial addition chain of dimension k computing [n0,...,nk-1]
- Output:The element x0n0...xk-1nr-1
Addition sequence
An addition sequence for the set of integer S ={n0, ...,nr-1} is an addition chain v that contains every element of S.
For example, an addition sequence computing
- {47,117,343,499}
is
- (1,2,4,8,10,11,18,36,47,55,91,109,117,226,343,434,489,499).
It's possible to find addition sequence from vectorial addition chains and vice versa, so they are in a sense dual.[1]
See also
References
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- ↑ Cohen, H., Frey, G. (editors): Handbook of elliptic and hyperelliptic curve cryptography. Discrete Math. Appl., Chapman & Hall/CRC (2006)