[Jprogramming] Membership using interval index

[Henry Rich]

It would be reasonable to use fit to specify test-for-ordered:

e.!.0 1

would say, 'exact, y is probably sorted'

You would need a way to indicate tolerant comparison.  Maybe

e.!.__ 1

would say 'tolerant, default tolerance, y is probably sorted'.

Better: any negative tolerance could call for default tolerance.


You would want something the whole i. family could benefit from.

Henry Rich

Roger Hui wrote:
> e signals error if the left argument has an
> item larger than the largest item in the right:
> 
>    1e9 2e9 e P
> |index error: e
> |   1000000000 2000000000     e P
> 
> I wonder if the interpreter should look for
> sorted y in x e. y as a special case.
> 
> 
> 
> ----- Original Message -----
> From: John Randall <randall at andromeda.rutgers.edu>
> Date: Wednesday, May 20, 2009 13:56
> Subject: [Jprogramming] Membership using interval index
> To: Programming forum <programming at jsoftware.com>
> 
>> I have been trying to write a version of e. for sorted arrays, using
>> I. , since it appears to offer performance benefits.  My 
>> attempt is
>> the verb e below:
>>
>> e=:[ = ] {~ I.~
>>
>> time=:6!:2
>> P=:i.&.(p:^:_1) 1e6
>>
>>    10 time '(i.1000) e P'
>> 0.0001042
>>    10 time '(i.1000) e. P'
>> 0.0069257
>>
>> Is this a sensible approach, or are there better ways to do it?
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