matrix multiplication (newbie question)

Sven Schreiber svetosch at gmx.net
Wed Nov 8 16:00:03 CST 2006


Johannes Loehnert schrieb:
> Hi,
> 
> in extension to the previous answers, I'd like to say that it is strongly 
> preferable to use dot(A,dot(B,C)) or dot(dot(A,B),C) instead of A*B*C.
> 
> The reason is that with dot(), you can control of which operation is performed 
> first, which can *massively* influence the time needed, depending on the 
> involved matrices. A*B*C will always be evaluated left-to-right (if I 
> remember correctly).
> 

Well what about A*(B*C)?

-------------------------------------------------------------------------
Using Tomcat but need to do more? Need to support web services, security?
Get stuff done quickly with pre-integrated technology to make your job easier
Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo
http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642




More information about the Numpy-discussion mailing list