[R] Matrix mulitplication

Peter Dalgaard p.dalgaard at biostat.ku.dk
Tue Feb 17 00:35:03 CET 2004


(Ted Harding) <Ted.Harding at nessie.mcc.ac.uk> writes:

> Sorry! Missed a trick here:
> 
>     At <- t(A)
>     Bt <- t(B)
>     E  <- B%*%A
>     Et <- t(E)
>     A%*%solve(Et%*%E + C)%*%Et%*%D
> 
> (saves 2 multiplications at the relatively cheap cost of 1 transpose)

Well, you might consider getting rid of the first two transposes since
you're not actually using them for anything....


-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)             FAX: (+45) 35327907




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