Re: sum and for loop too slow...

Hi,
1000000 are many, so you should be careful about what you do.

You sum up 27*100000 times more or less the same, so the first
suggestion I have is:devide sum(0:0.001:2000+zeta(i,j)) into
sum(0:0.001:1995)+sum(1995.001:0.001:2000+zeta)

And the first part is not dependent on i,j ...

Titus

"Evan" <evanmason@xxxxxxxxx> schrieb im Newsbeitrag
news:1146661276.745599.229150@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Hi, can anyone suggest a way to speed up the following bit of code:


pressure = zeros(27,1000000);

for i=1:27
for j=1:1000000
pressure(i,j) = sum(0 : 0.001 : 2000+zeta(i,j));
end
end

'zeta' is an array (27,1000000) containing random floats between -5 and
5. Ideally I'd like to get rid of the 'for' loops as these are taking
all the time, but not sure how/if possible?

Many thanks,

Evan



.

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