Changeset 30bb07 in git for Singular/LIB/presolve.lib

Timestamp:

May 29, 2009, 12:07:01 PM (15 years ago)

Author:

Hans Schönemann <hannes@…>

Branches:

(u'spielwiese', 'fe61d9c35bf7c61f2b6cbf1b56e25e2f08d536cc')

Children:

667a9c0d30591ae4298e16548bf5886508bd3968

Parents:

a2b50cb2b820afde605ed45cb52930a5913927cc

Message:

*hannes: 1.33


git-svn-id: file:///usr/local/Singular/svn/trunk@11855 2c84dea3-7e68-4137-9b89-c4e89433aadc

File:

• Singular/LIB/presolve.lib (modified) (13 diffs)

Singular/LIB/presolve.lib

@@ -1 +1 @@
 ///////////////////////////////////////////////////////////////////////////////
-version="$Id: presolve.lib,v 1.34 2009-05-29 09:26:48 Singular Exp $";
+//changed GMG 20.5.09: degreepart, linearpart, elimpart
+///////////////////////////////////////////////////////////////////////////////
+version="$Id: presolve.lib,v 1.35 2009-05-29 10:07:01 Singular Exp $";
 category="Symbolic-numerical solving";
 info="
@@ -92 +94 @@
           (default: v = 1,...,1)
          _[2]: remaining generators of id
+NOTE:    if id is of type int/number/poly it is converted to ideal, if id is
+         of type intmat/matrix/vector to module and then the corresponding
+         generators are computed
 EXAMPLE: example degreepart; shows an example
 "
@@ -144 +149 @@
          _[1]: generators of id of total degree <= 1
          _[2]: remaining generators of id
+NOTE:    all variables have degree 1 (independent of ordering of basering)
 EXAMPLE: example linearpart; shows an example
 "
@@ -179 +185 @@
 "
 {
-   int ii,n,k;
-   string o, newo;
+   int ii,n,k,ringchange;
+   string o;
    intvec getoption = option(get);
    option(redSB);
@@ -194 +200 @@
    if ( n < nvars(BAS) )
    {
-      rest = maxi[n+1..nvars(BAS)];
+      rest = maxi[n+1..nvars(BAS)];     //variables which are not substituted
    }
    attrib(rest,"isSB",1);
@@ -205 +211 @@
    //## gmg, geŠndert 9/2008: interred sehr lange z.B. bei Leonard1 in normal,
    //daher interred ersetzt durch: std nur auf linearpart angewendet
-   //Ordnung muss global sein, sonst egal (da Lin affin linear)
-
-//--------------- replace ordering by dp if it is not global -----------------
-   if ( ord_test(BAS) <= 0 )
-   {
+   //Wechsel zu dp Ordnung (da Lin affin linear)
+
+//--------------- replace ordering different from dp by dp -------------------
+   o = "dp("+string(n)+")";
+   if( ! find(ordstr(BAS),o) or find(ordstr(BAS),"a") )
+   {
+      ringchange = 1;                         //remember change of ring
       intvec V;
       V[n]=0; V=V+1;                          //weights for dp ordering
@@ -230 +238 @@
       lin = lin,id1;
       lin = std(lin);
-      id = simplify(NF(id,lin),2);   //instead of subst
+      id = simplify(NF(id,lin),2);   //instead of subst, (### is faster)
       id1 = linearpart(id)[1];
    }
@@ -275 +283 @@
 //------------------ go back to original ring end return  ---------------------
 
-   if ( ord_test(BAS) <= 0  )           //i.e there was a ring change
+   if ( ringchange  )                   //i.e there was a ring change
    {
       setring BAS;
@@ -347 +355 @@
 
    list L = elimlinearpart(i,n);
+   ideal lin, eva, sub, neva, phi = L[1], L[2], L[3], L[4], L[5];
    if ( e == 0 )
    {
        return(L);
    }
-   ideal lin, eva, sub, neva, phi = L[1], L[2], L[3], L[4], L[5];
+
 //-------- direct substitution of variables if possible and if e!=0 -----------
 // first find terms lin1 in lin of pure degree 1 in each polynomial of lin
@@ -382 +391 @@
 -z ergibt ich auch i[2]-z*i[3] mit option(redThrough)
 statt interred kann man hier auch NF(i,i[3])+i[3] verwenden
-hier liefert elimpart(i) 2 Substitutionen (x,y) elimpart(interred(i))
+hier lifert elimpart(i) 2 Substitutionen (x,y) elimpart(interred(i))
 aber 3 (x,y,z)
 Da interred oder NF aber die Laenge der polys vergroessern kann, nicht gemacht
@@ -421 +430 @@
    //kin = polys of lin which contained a pure degree 1 part.
    kin = simplify(kin,2);
-   l = ncols(kin);                    //l != 0 since lin1 != 0
+   l = size(kin);                      //l != 0 since lin1 != 0
    poly p,kip,vip, cand;
    int count=1;
@@ -432 +441 @@
             {
                p = kin[kk]/var(ii);
-               if ( deg(p) == 0 )  //this means that kin[kk]= p*var(ii) + h,
-                                   //with p=const and h not depending on var(ii)
+               //if ( deg(p) == 0 )
+               //old test, does not work if some var has deg 0
+               //geaendert Mai 09 gmg
+
+               if( p!=0 & p == jet(p,0) )
+                   //this means that kin[kk]= p*var(ii) + h,
+                   //with p=const !=0 and h not depending on var(ii)
                {
                   //we look for the shortest candidate to substitute var(ii)
@@ -448 +462 @@
                   }
                 }
-            }     
+            }
             if ( cand != 0 )
             {
                   p = cand/var(ii);
-                  kip = cand/p;      //normalized polynomial of kin w.r.t var(ii)
+                  kip = cand/p;     //normalized polynomial of kin w.r.t var(ii)
                   eva = eva+var(ii); //var(ii) added to list of elimin. vars
                   neva[ii] = 0;