Editing Quadratic sieve (section)

==Parameters from realistic example==

To illustrate typical parameter choices for a realistic example on a real implementation including the multiple polynomial and large prime optimizations, the tool [http://sourceforge.net/projects/msieve/ msieve] was run on a 267-bit [[semiprime]], producing the following parameters:

* Trial factoring cutoff: 27 bits
* Sieve interval (per polynomial): 393216 (12 blocks of size 32768)
* Smoothness bound: 1300967 (50294 primes)
* Number of factors for polynomial ''A'' coefficients: 10 ''(see [[#Multiple polynomials|Multiple polynomials]] above)''
* Large prime bound: 128795733 (26 bits) ''(see [[#Large primes|Large primes]] above)''
* Smooth values found: 25952 by sieving directly, 24462 by combining numbers with large primes
* Final matrix size: 50294 &times; 50414, reduced by filtering to 35750 &times; 35862
* Nontrivial dependencies found: 15
* Total time (on a 1.6&nbsp;GHz UltraSPARC III): 35 min 39 seconds
* Maximum memory used: 8 MB