Re: strange booleanconvert behavior?

*To*: mathgroup at smc.vnet.net*Subject*: [mg127239] Re: strange booleanconvert behavior?*From*: Peter Pein <petsie at dordos.net>*Date*: Wed, 11 Jul 2012 02:16:42 -0400 (EDT)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*Delivered-to*: mathgroup-newout@smc.vnet.net*Delivered-to*: mathgroup-newsend@smc.vnet.net*References*: <jtgbqo$49b$1@smc.vnet.net>

Am 10.07.2012 06:42, schrieb Francisco Gutierrez: > Dear Group: > Say I have the following expression: > num1={{a,b,c,d},{a,b,c,e},{a,b,c,f},{a,b,c,g},{a,b,c,h},{a,b,c,i},{a,b,c,j},{a,b,c,k},{a,b,c,l},{a,b,c,m},{a,b,c,n}} > > I transform it into a logical expression: > n= > um2=Apply[Or,Apply[And,#]&/@num1] > > I want to simplify this to a CNF, and the obvious function to use is Boolean Convert. Suppose I apply it to NINE elements of num2: > BooleanConvert[Take[num2,9],"CNF"] > The output is > a&&b&&c&&(d||e||f||g||h||i||j||k||l) > > It works perfectly well! > > However, if I apply BooleanConvert to the whole expression I get back a bunch of crap. Also if I apply it to 10 elements of num2. > In sum, it appears that BooleanConvert only works well for 9 expressions or less. Tried this with other two examples, and found > exactly the same result. > > All this in Mathematica 8 > > Can somebody help me? > Francisco > Hi Francisco, using similar to your 'num2' num2 = Or @@ Table[And[a, b, c, last], {last, ToExpression@CharacterRange["d", "z"]}] I observed that FullSimplify works up to seventeen terms: FullSimplify[Take[num2, 17]] results in a && b && c && (d || e || f || ... || t) I've got no idea what the "ConversionMethodParameters" in the following input are but I multiplied suspicious values by 100 and it works :) SetSystemOptions[ "BooleanComputationOptions" -> {"ConversionMethodParameters" -> {1200, 1., 10000, False}}]; BooleanConvert[num2, "CNF"] results in a && b && c && (d || e || f || ... || z) Any esoteric knowledge about the SystemOptions and how Experimental`SystemOptionsEditor[] works are welcome and highly appreciated. Greetings, Peter