Changeset 15e59a in git for Singular/LIB/general.lib

Timestamp:

Nov 16, 2006, 11:56:18 AM (16 years ago)

Author:

Hans Schönemann <hannes@…>

Branches:

(u'jengelh-datetime', 'ceac47cbc86fe4a15902392bdbb9bd2ae0ea02c6')(u'spielwiese', 'a800fe4b3e9d37a38c5a10cc0ae9dfa0c15a4ee6')

Children:

84375a9ec076945718aaeff4eda7ff2df15f6cd9

Parents:

7dfc59a71d8f9f93f9fb6c331496cdf9b42a89ed

Message:

*king: new sum/lsum


git-svn-id: file:///usr/local/Singular/svn/trunk@9489 2c84dea3-7e68-4137-9b89-c4e89433aadc

File:

• Singular/LIB/general.lib (modified) (5 diffs)

Singular/LIB/general.lib

@@ -3 +3 @@
 //eric, added absValue 11.04.2002
 ///////////////////////////////////////////////////////////////////////////////
-version="$Id: general.lib,v 1.50 2006-07-20 14:51:56 Singular Exp $";
+version="$Id: general.lib,v 1.51 2006-11-16 10:55:58 Singular Exp $";
 category="General purpose";
 info="
@@ -958 +958 @@
 }
 ///////////////////////////////////////////////////////////////////////////////
+
+proc lsum (int n, list l)
+{ if (n>10)
+  { return( lsum(n/2,list(l[1..(n/2)])) + lsum(n-n/2, list(l[(n/2+1)..n])) );
+  }
+  else
+  { def Summe=l[1];
+    for (int i=2;i<=n;i++)
+    { Summe=Summe+l[i];
+    }
+    return(Summe);
+  }
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
 proc sum (id, list #)
 "USAGE:    sum(id[,v]); id ideal/vector/module/matrix/intvec/intmat/list,
@@ -1013 +1029 @@
    }
    if( ty=="int" or ty=="intvec" or ty=="intmat" )
-   {
+   {                                                 //case: id = intvec
       if ( ty == "int" ) { intmat S =id; }
       else { intmat S = intmat(id); }
       intvec i = S[1..nrows(S),1..ncols(S)];
       kill id;
-      intvec id = i;                                 //case: id = intvec
+      intvec id = i;
    }
 //------------------- consider intvec v and empty sum  -----------------------
@@ -1035 +1051 @@
 //-------------------------- finally, add objects  ---------------------------
    n = size(id);
-   def f(1) = id[1];
-   for( j=2; j<=n; j=j+1 ) { def f(j)=f(j-1)+id[j]; }
-   return(f(n));   int n,j,tt;
+   if (n>10)
+   { return( lsum(n/2,list(id[1..(n/2)])) + lsum(n-n/2, list(id[(n/2+1)..n])) );
+   }
+   else
+   { def Summe=id[1];
+     for (int lauf=2;lauf<=n;lauf++)
+     { Summe=Summe+id[lauf];
+     }
+     return(Summe);
+   }
 }
 example
 {  "EXAMPLE:"; echo = 2;
-   ring r= 0,(x,y,z),dp;
+   ring r1 = 0,(x,y,z),dp;
    vector pv = [xy,xz,yz,x2,y2,z2];
    sum(pv);
@@ -1050 +1073 @@
    intvec iv = 1,2,3,4,5,6,7,8,9;
    sum(iv,2..4);
-}
+   iv = intvec(1..100);
+   sum(iv);
+   ring r2 = 0,(x(1..10)),dp;
+   sum(x(3..7),intvec(1,3,5));
+}
+///////////////////////////////////////////////////////////////////////////////
+
+
 ///////////////////////////////////////////////////////////////////////////////