8 Jun
2005
8 Jun
'05
7:07 a.m.
On Wed, Jun 08, 2005 at 09:50:42AM +0100, Simon Jenkins wrote:
Suppose I sum a vector of 5 million integers and it
takes 6 seconds. And
assume - (generously![1]) - that I switch to using an array and now it
only takes 1 second. Hmmm... a 6 * speedup! So I look to see where else
my code could benefit from this super performance boost.
Aha! Here's a vector of 5,000 oscillator structures, and it takes 5
seconds to initialise them all. Switch to using an array and... erm...
now it only takes 4.995 seconds to initialise them all.
When all you need is the random access of a C array (or maybe even less,
just sequential acces), and this is something you should know _before
writing one letter of code_, why waste your time by writing it first using
a vector and changing it afterwards ? Just write it using an array _from
the start_. It takes no more time or effort than using a vector.
--
FA