Changeset 920a1e in git

Timestamp:

Mar 2, 2010, 7:56:03 PM (13 years ago)

Author:

Viktor Levandovskyy <levandov@…>

Branches:

(u'spielwiese', '0d6b7fcd9813a1ca1ed4220cfa2b104b97a0a003')

Children:

92f22582e01a56afdab3e7f9e6f70f47bf4230e5

Parents:

e1cb99e6603e14230e36591822670ccc7436520a

Message:

*levandov: protocol added, slimgb set as default choice, minor fixes 

git-svn-id: file:///usr/local/Singular/svn/trunk@12578 2c84dea3-7e68-4137-9b89-c4e89433aadc

File:

• Singular/LIB/ncdecomp.lib (modified) (17 diffs)

Singular/LIB/ncdecomp.lib

@@ -14 +14 @@
 PROCEDURES:
 CentralQuot(M,G);       central quotient M:G,
-CentralSaturation(M,T); central saturation ((M:T):...):T) ( = M:T^{\infty}),
+CentralSaturation(M,T); central saturation ((M:T):...):T) ( = M:T^infinity),
 CenCharDec(I,C);        decomposition of I into central characters w.r.t. C
 IntersectWithSub(M,Z);  intersection of M with the subalgebra, generated by pairwise commutative elements of Z.
@@ -35 +35 @@
 static proc CharKernel(list L, int i)
 {
+ // todo: think on more effective way of doing it...
 // compute \cup L[j], j!=i
   int sL = size(L);
@@ -57 +58 @@
   }
 //  print("intersecting kernels...");
-  module Cres = intersect(Li[1..size(Li)]);
+  module Cres = intersect(Li[1..size(Li)]); // uses std, try modulo!
   return(Cres);
 }
@@ -97 +98 @@
   if (attrib(A,"isSB")!=1)
   {
-    A = std(A);
+    A = slimgb(A);
   }
   if (attrib(B,"isSB")!=1)
   {
-    B = std(B);
+    B = slimgb(B);
   }
   int ANSWER = 1;
@@ -152 +153 @@
    I = std(I);
    poly C=4*e*f+h^2-2*h;  // C in Z(U(sl2)), the central element
-   ideal G = (C-8)*(C-24);  // G normal factor in Z(U(sl2)), subideal in the center
+   ideal G = (C-8)*(C-24);  // G normal factor in Z(U(sl2)) as an ideal in the center
    ideal R = CentralQuot(I,G);  // same as I:G
    R;
@@ -239 +240 @@
     ERROR("ideal in the 2nd argument is not in the center of the base ring!");
   }
-
+  int ppl = printlevel-voice+2;
 // M = A/I
 //1. Find the Zariski closure of Supp_Z M
@@ -270 +271 @@
   }
   @Ker = @Ker,I;
-  ideal @JcapZ = eliminate(@Ker,t);
+  //  ideal @JcapZ = eliminate(@Ker,t);
+  dbprint(ppl,"// -1-1- starting the computation of preimage in Z");
+  dbprint(ppl-1, @Ker);
+  ideal @JcapZ = slimgb(@Ker);
+  @JcapZ = nselect(@JcapZ,intvec(1..nvars(@A)));
+  dbprint(ppl,"// -1-2- finished the computation of preimage in Z");
+  dbprint(ppl-1, @JcapZ);
 // do not forget parameters of a basering!
+// hmmm: todo ringlist
   string strZ="ring @@Z=("+charstr(@A)+"),(@z(1.."+string(sZ)+")),dp;";
 //  print(strZ);
@@ -277 +285 @@
   setring @@Z;
   ideal @JcapZ = imap(@ZplusA,@JcapZ);
-  @JcapZ = std(@JcapZ);
+  dbprint(ppl,"// -1-3- starting the cosmetic Groebner basis in Z");
+  @JcapZ = slimgb(@JcapZ); // evtl. groebner?
 //  @JcapZ;
+  dbprint(ppl,"// -1-4- finished the cosmetic Groebner basis in Z");
+  dbprint(ppl-1, @JcapZ);
   int sJ = vdim(@JcapZ);
+  dbprint(ppl,"// -1-5- the K-dimension of support is "+string(sJ));
   if (sJ==-1)
   {
@@ -287 +299 @@
 //  print(@JcapZ);
 // 2. compute the min.ass.primes of the ideal in the center
+  dbprint(ppl,"// -2-1- starting the computation of minimal primes in Z");
   list @L = minAssGTZ(@JcapZ);
   int sL = size(@L);
+  dbprint(ppl,"// -2-2- finished the computation of " + string(sL)+ " minimal primes in Z");
 //  print("etL:");
 //  @L;
@@ -294 +308 @@
   if (sL ==1)
   {
+    dbprint(ppl-1,"// -2-3- the whole module is gen. weight module itself");
     setring @A;
     map @M = @@Z,Center[1..size(Center)];
@@ -308 +323 @@
       @R[2] = ideal(@R[2]);
     }
-    @R[2] = std(@R[2]);
+    dbprint(ppl-1,"// -2-4- final cosmetic Groebner basis");
+    @R[2] = slimgb(@R[2]);
     @R[3] = vdim(@R[2]);
-    return(@R);
-  }
+    return(list(@R)); // for compliance with output a list
+  }
+  dbprint(ppl-1,"// -2-3- there are several characters");
+  dbprint(ppl,"// -*- computing Groebner bases of components (commutative)");
   list @CharKer;
   for(i=1; i<=sL; i++)
   {
-    @L[i] = std(@L[i]);
-  }
+    @L[i] = slimgb(@L[i]);
+  }
+  dbprint(ppl,"// -*- finished computing Groebner bases of components");
 // 3. compute the intersections of characters
+  dbprint(ppl,"// -3- compute the intersections of characters");
   for(i=1; i<=sL; i++)
   {
     @CharKer[i] = CharKernel(@L,i);
   }
-//  print("Charker:");
-//  @CharKer;
+  dbprint(ppl,"// -3- the intersections of characters is done");
+  //  dbprint(ppl-1,@CharKer);
 // 4. Go back to the algebra and compute central saturations
   setring @A;
@@ -329 +349 @@
   list L = @M(@CharKer);
   list R,@R;
+  dbprint(ppl,"// -4- compute the central saturations");
+  dbprint(ppl-1,@CharKer);
   for(i=1; i<=sL; i++)
   {
@@ -341 +363 @@
       @R[2] = ideal(@R[2]);
     }
-    @R[2] = std(@R[2]);
+    @R[2] = slimgb(@R[2]);
     @R[3] = vdim(@R[2]);
      R[i] = @R;
   }
+  dbprint(ppl,"// -4- central saturations are done");
   return(R);
 }
 example
-{ "EXAMPLE:"; echo = 2;
+{ "EXAMPLE:"; echo = 2; printlevel=0;
    option(returnSB);
    def a = makeUsl2(); // U(sl_2) in characteristic 0
@@ -401 +424 @@
       if (p!=0)
       {
-        "Error: generators of the subalgebra do not commute.";
-        return(ideal(0));
+        ERROR("generators of the subalgebra do not commute.");
+        //        return(ideal(0));
       }
     }
@@ -410 +433 @@
   setring B;
   string s1,s2;
+  // todo: make ringlist from it!
   s1 = "ring @Z = (";
   s2 = s1 + charstr(basering) + "),(z(1.." + string(nz)+")),Dp";
@@ -417 +441 @@
   map F = @Z,Z;
   setring @Z;
-  ideal PreM = preimage(B,F,M);
-  PreM = std(PreM);
+  ideal PreM = preimage(B,F,M); // reformulate using gb engine? todo?
+  PreM = slimgb(PreM);
   setring B;
   ideal T = F(PreM);
@@ -428 +452 @@
   ring R=(0,a),(e,f,h),Dp;
   matrix @d[3][3];
-  @d[1,2]=-h;
-  @d[1,3]=2e;
-  @d[2,3]=-2f;
+  @d[1,2]=-h;   @d[1,3]=2e;   @d[2,3]=-2f;
   def r = nc_algebra(1,@d); setring r; // parametric U(sl_2)
   ideal I = e,h-a;