=================================================================== RCS file: /home/cvs/OpenXM/src/asir-doc/parts/groebner.texi,v retrieving revision 1.13 retrieving revision 1.14 diff -u -p -r1.13 -r1.14 --- OpenXM/src/asir-doc/parts/groebner.texi 2004/09/13 09:23:30 1.13 +++ OpenXM/src/asir-doc/parts/groebner.texi 2004/09/14 01:32:34 1.14 @@ -1,4 +1,4 @@ -@comment $OpenXM: OpenXM/src/asir-doc/parts/groebner.texi,v 1.12 2003/12/27 11:52:07 takayama Exp $ +@comment $OpenXM: OpenXM/src/asir-doc/parts/groebner.texi,v 1.13 2004/09/13 09:23:30 noro Exp $ \BJP @node グレブナ基底の計算,,, Top @chapter グレブナ基底の計算 @@ -1069,7 +1069,7 @@ beforehand, and some heuristic trial may be inevitable より一般的なものとなる. \E \BEG -Term orders introduced in the previous section can be generalized +Term orderings introduced in the previous section can be generalized by setting a weight for each variable. \E @example @@ -1097,9 +1097,9 @@ In this example, the weights for the first, the second variable are set to 1, 2 and 3 respectively. Therefore the total degree of @code{<<1,1,1>>} under this weight, which is called the weight of the monomial, is @code{1*1+1*2+1*3=6}. -By setting weights, different term orders can be set under a term -order type. For example, a polynomial can be made weighted homogeneous -by setting an appropriate weight. +By setting weights, different term orderings can be set under a type of +term ordeing. In some case a polynomial can +be made weighted homogeneous by setting an appropriate weight. \E \BJP @@ -1131,7 +1131,62 @@ is also considered as a refinement of comparison by we It compares two terms by using a weight vector whose elements corresponding to variables in a block is 1 and 0 otherwise, then it applies a tie breaker. +\E +\BJP +weight vector の設定は @code{dp_set_weight()} で行うことができる +が, 項順序を指定する際の他のパラメタ (項順序型, 変数順序) と +まとめて設定できることが望ましい. このため, 次のような形でも +項順序が指定できる. +\E +\BEG +A weight vector can be set by using @code{dp_set_weight()}. +However it is more preferable if a weight vector can be set +together with other parapmeters such as a type of term ordering +and a variable order. This is realized as follows. +\E + +@example +[64] B=[x+y+z-6,x*y+y*z+z*x-11,x*y*z-6]$ +[65] dp_gr_main(B|v=[x,y,z],sugarweight=[3,2,1],order=0); +[z^3-6*z^2+11*z-6,x+y+z-6,-y^2+(-z+6)*y-z^2+6*z-11] +[66] dp_gr_main(B|v=[y,z,x],order=[[1,1,0],[0,1,0],[0,0,1]]); +[x^3-6*x^2+11*x-6,x+y+z-6,-x^2+(-y+6)*x-y^2+6*y-11] +[67] dp_gr_main(B|v=[y,z,x],order=[[x,1,y,2,z,3]]); +[x+y+z-6,x^3-6*x^2+11*x-6,-x^2+(-y+6)*x-y^2+6*y-11] +@end example + +\BJP +いずれの例においても, 項順序は option として指定されている. +最初の例では @code{v} により変数順序を, @code{sugarweight} により +sugar weight vector を, @code{order}により項順序型を指定している. +二つ目の例における @code{order} の指定は matrix order と同様である. +すなわち, 指定された weight vector を左から順に使って weight の比較 +を行う. 三つ目の例も同様であるが, ここでは weight vector の要素を +変数毎に指定している. 指定がないものは 0 となる. 三つ目の例では, +@code{order} による指定では項順序が決定しない. この場合には, +tie breaker として全次数逆辞書式順序が自動的に設定される. +この指定方法は, @code{dp_gr_main}, @code{dp_gr_mod_main} など +の組み込み関数でのみ可能であり, @code{gr} などのユーザ定義関数 +では未対応である. +\E +\BEG +In each example, a term ordering is specified as options. +In the first example, a variable order, a sugar weight vector +and a type of term ordering are specified by options @code{v}, +@code{sugarweight} and @code{order} respectively. +In the second example, an option @code{order} is used +to set a matrix ordering. That is, the specified weight vectors +are used from left to right for comparing terms. +The third example shows a variant of specifying a weight vector, +where each component of a weight vector is specified variable by variable, +and unspecified components are set to zero. In this example, +a term order is not determined only by the specified weight vector. +In such a case a tie breaker by the graded reverse lexicographic ordering +is set automatically. +This type of a term ordering specification can be applied only to builtin +functions such as @code{dp_gr_main()}, @code{dp_gr_mod_main()}, not to +user defined functions such as @code{gr()}. \E \BJP