Defactoring: Difference between revisions

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=== minors'n'back defactoring ===
=== MADAM defactoring ===


Another technique which was experimented with took advantage of the fact that the list of minor determinants (or simply "minors") of a mapping is guaranteed to include any common factor as its entries' GCD. So, if one simply converted a mapping to its list of minors, removed the GCD (at which point you would have what in RTT is called a [[User:Cmloegcmluin/RTT_How-To#multimaps|canonical multimap]], or [[wedgie]]), and then performed an "anti-minors" operation to get back to a mapping form, any common factors should be removed.  
Another technique which was experimented with took advantage of the fact that the list of minor determinants (or simply "minors") of a mapping is guaranteed to include any common factor as its entries' GCD. So, if one simply converted a mapping to its list of minors, removed the GCD (at which point you would have what in RTT is called a [[User:Cmloegcmluin/RTT_How-To#multimaps|canonical multimap]], or [[wedgie]]), and then performed an "anti-minors" operation to get back to a mapping form, any common factors should be removed.  


Following Gene Ward Smith's method for computing anti-minors as described [[Mathematical_theory_of_regular_temperaments#Wedgies|here]] and [[Basic_abstract_temperament_translation_code|here]], the anti-minors method was developed. Unfortunately it required defactoring to work. So it couldn't be used as part of a defactoring solution itself.
Inspired by Gene Ward Smith's method for computing anti-minors as described [[Mathematical_theory_of_regular_temperaments#Wedgies|here]] and [[Basic_abstract_temperament_translation_code|here]], an anti-minors method was implemented in Wolfram Language. It was found that a defactoring algorithm based on '''M'''inors '''A'''nd '''D'''ivide-out-GCG, '''A'''nti-'''M'''inors, or '''MADAM defactoring''', does indeed work. However, it runs 10 to 20 times slower than Smith defactoring and column Hermite defactoring, and it is not compellingly easier to understand than either of them, so it is not considered to be of significant interest.


=== duality in LA and VEA ===
=== duality in LA and VEA ===