On Mon, 25 Aug 2008 03:48:54 +0000, Daniel Lenski wrote:
> * it's fast enough for 100,000 determinants, but it bogs due to
> all the temporary arrays when I try to do 1,000,000 determinants
> (=72 MB array)
I've managed to reduce the memory usage significantly by getting the
number of temporary arrays down to exactly two:
def det3(ar):
a=ar[...,0,0]; b=ar[...,0,1]; c=ar[...,0,2]
d=ar[...,1,0]; e=ar[...,1,1]; f=ar[...,1,2]
g=ar[...,2,0]; h=ar[...,2,1]; i=ar[...,2,2]
t=a.copy(); t*=e; t*=i; tot =t
t=b.copy(); t*=f; t*=g; tot+=t
t=c.copy(); t*=d; t*=h; tot+=t
t=g.copy(); t*=e; t*=c; tot-=t
t=h.copy(); t*=f; t*=a; tot-=t
t=i.copy(); t*=d; t*=b; tot-=t
return tot
Now it runs very fast with 1,000,000 determinants to do (<10X the time
required to do 100,000) but I'm still worried about the stability with
real-world data.
Dan
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