Changeset 9a92d9 in git

Timestamp:

Mar 31, 2005, 1:45:00 PM (18 years ago)

Author:

Michael Brickenstein <bricken@…>

Branches:

(u'spielwiese', '8d54773d6c9e2f1d2593a28bc68b7eeab54ed529')

Children:

1903b7f98b7252fcf5bf02cbecaa4d79d4d87556

Parents:

e707b8e1bd2fb81722355c5ae845fef978f73085

Message:

*bricken: multinomial coeff. clever calculated


git-svn-id: file:///usr/local/Singular/svn/trunk@7803 2c84dea3-7e68-4137-9b89-c4e89433aadc

File:

• kernel/fast_mult.cc (modified) (4 diffs)

kernel/fast_mult.cc

@@ -480 +480 @@
 static void MC_iterate(poly f, int n, ring r, int f_len,number* facult, int* exp,poly* f_terms,kBucket_pt erg_bucket,int pos,int sum, number coef, poly & zw, poly tmp, poly** term_pot){
   int i;
-
+  
   if (pos<f_len-1){
     poly zw_l=NULL;
+    number new_coef;
     for(i=0;i<=n-sum;i++){
       exp[pos]=i;
-      number new_coef=n_IntDiv(coef,facult[i],r);
+      if(i==0){
+        new_coef=n_Copy(coef,r);
+      }
+      else {
+        number old=new_coef;
+        number old_rest=n_Init(n-sum-(i-1),r);
+        new_coef=n_Mult(new_coef,old_rest,r);
+        n_Delete(&old_rest,r);
+        n_Delete(&old,r);
+        number i_number=n_Init(i,r);
+        old=new_coef;
+        new_coef=n_IntDiv(new_coef,i_number,r);
+        n_Delete(&old,r);
+        n_Delete(&i_number,r);
+      }
+      //new_coef is 
+      //(n                          )
+      //(exp[0]..exp[pos] 0 0 0 rest)
       poly zw_real=NULL;
       MC_iterate(f, n, r, f_len,facult, exp,f_terms,erg_bucket,pos+1,sum+i,new_coef,zw_real,tmp,term_pot);
@@ -494 +512 @@
         zw_l=zw_real;
       }
-      n_Delete(& new_coef,r);
-    }
+      //n_Delete(& new_coef,r);
+    }
+    n_Delete(&new_coef,r);
     if (pos==f_len-2){
       int len=n-sum+1;
@@ -505 +524 @@
     i=n-sum;
     exp[pos]=i;
-    number new_coef=n_IntDiv(coef,facult[i],r);
+    number new_coef=nCopy(coef);//n_IntDiv(coef,facult[i],r); //really consumed???????
     buildTermAndAdd(n,facult,f_terms,exp,f_len,erg_bucket,r, new_coef,zw, tmp,term_pot);
     // n_Delete(& new_coef,r);
@@ -554 +573 @@
   poly zw=NULL;
   poly tmp=p_Init(r);
-  MC_iterate(f,n,r,f_len,&facult[0], &exp[0], &f_terms[0],erg_bucket,0,0,facult[n],zw,tmp, term_potences);
-
-
-
+  number one=n_Init(1,r);
+  MC_iterate(f,n,r,f_len,&facult[0], &exp[0], &f_terms[0],erg_bucket,0,0,one/*facult[n]*/,zw,tmp, term_potences);
+
+
+  n_Delete(&one,r);