OpenEuphoria

RE: hash

• Posted by Derek Parnell <Derek.Parnell at SYD.RABOBANK.COM> Jun 20, 2002
• 423 views

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My recommendation is rather than supply the hashing parameters like this,
supply the expected number of elements instead. Other than that, you need to
experiment. The speed is dependant on the number of elements and the
elements' contents. The sequence of the elements is not relevant.

> -----Original Message-----
> From: tone.skoda at gmx.net [mailto:tone.skoda at gmx.net]
> Sent: Friday, 21 June 2002 14:32
> To: EUforum
> Subject: hash
> 
> 
> 
> I want to use hash table into which to save some formulas 
> (strings) to later
> (when I get new formula) check
> if that formula is already in hash table (was already 
> evaluated once), data
> is discarded.
> I'm using hash.e from Derek Parnell. I create table like this:
> Got_formulas_ht = Hash_NewTable( {40,40,10,20,20} )
> and I have no idea what this argument should be. If I change 
> it the speed
> doesn't change.
> So I'm asking how should that argument look?
> Size of table is unknown, grows infinite, I get about 300 
> unique formulas
> per 30 seconds.
> BTW this is strange: if I use sorted sequence and binary 
> search it it works
> with same speed.
> 
> Here are some sample formulas which I save into hash table:
> 
> 4*a
> 3*a+b
> 3*a+c
> 3*a+d
> 2*a+2*b
> 2*a+b+c
> 2*a+b+d
> 2*a+2*c
> 2*a+c+d
> 2*a+2*d
> a+3*b
> a+2*b+c
> a+2*b+d
> a+b+2*c
> a+b+c+d
> a+b+2*d
> a+3*c
> a+2*c+d
> a+c+2*d
> a+3*d
> ...
> pow(b,pow(pow(b,b),a))
> pow(b,pow(pow(b,b),b))
> pow(b,pow(pow(b,b),c))
> ...
> (b+2*c)*b
> (b+2*c)*c
> (b+2*c)*d
> a*(b+c+d)
> ...
> 
> 
> 
> 

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