summation optimization
- To: mathgroup at smc.vnet.net
- Subject: [mg15326] summation optimization
- From: "Arturas Acus" <acus at itpa.lt>
- Date: Fri, 8 Jan 1999 04:15:16 -0500
- Sender: owner-wri-mathgroup at wolfram.com
Hello,
Suppose I wish to do multiple sums explicitly. Which one method is
preferable and how much time it can save? What about memory usage?
Method 1:
Sum[a[i,j],{i,?,?},{j,?,?}]+
Sum[b[i,k,m],{i,?,?},{k,!,!},{m,*,*}]
Method 2:
Sum[Sum[a[i,j],{j,?,?}]+Sum[b[i,k,m],{k,!,!},{m,*,*}],{i,?,?}]
Generally, how much grouping of similar indices can be effective?
Arturas Acus
Institute of Theoretical
Physics and Astronomy
Gostauto 12, 2600,Vilnius
Lithuania
E-mail: acus at itpa.lt
Fax: 370-2-225361
Tel: 370-2-612906