f=:4 :'y 0}x'
   a=:1e6?@#0
   timespacex'a=:a f 0'
0.004784 8.39053e6
   timespacex'a=:a 0}~0'
8e_6 1920

> On Apr 25, 2017, at 10:35 PM, Raul Miller <[email protected]> wrote:
> 
> What do you mean by "extra copies" and how have you been measuring that?
> 
> (Most of the time, a "copy" just means incrementing a reference count.
> There have been some exceptions, though, for boxed data, for example.)
> 
> Thanks,
> 
> -- 
> Raul
> 
> 
> On Tue, Apr 25, 2017 at 9:19 PM, Xiao-Yong Jin <[email protected]> wrote:
>> 
>>> On Apr 25, 2017, at 6:30 PM, Eric Iverson <[email protected]> wrote:
>>> 
>>> I have not followed this discussion at all and am probably way off base.
>>> 
>>> But how is:
>>> 
>>> allocate a few structures, and pass their pointers to the same function in
>>> separate callings
>>> 
>>> different from:
>>> 
>>> allocated a few globals in an agreed upon locale (call it the heap),  and
>>> pass their names (pointers) to the same verb in separate callings
>>> 
>>> ?
>> 
>> This question is actually right on spot, and I am struggling with this.
>> There are two aspects of this problem in my opinion.
>> 
>> 1. Unnecessary copying of data, given the current state of the in-place
>> operations in J.  To have a varied state in J, passing names to verb
>> essentially amounts to the following operations,
>> 
>>   State =. State Verb Control   NB. akin to usual functional style
>> 
>> Most of the time J would make unnecessary copies of the data in State.
>> I haven't found a reliable way to avoid extra copying, except for when
>> the 'Verb' here is a primitive.
>> 
>> 2. Inconvenience, if you want to maintain a set of inhomogeneous states.
>> I can do
>> 
>>   'State1A State1B State1C' = (State1A;State1B;State1C) Verb Control
>>   'State2A State2B State2C' = (State2A;State2B;State2C) Verb Control
>> 
>> Apart from copying/boxing, there are too many names to keep track of.
>> I would rather do
>> 
>>   Verb_1_ Control
>>   Verb_2_ Control
>> 
>> I guess I'm just more familiar with the latter, because it resembles
>> a common C function:
>> 
>>   void Verb(*Locale, const *Control)
>> 
>> Maybe I'm missing something in J.  Please feel free to correct me.
>> 
>> ----------------------------------------------------------------------
>> For information about J forums see http://www.jsoftware.com/forums.htm
> ----------------------------------------------------------------------
> For information about J forums see http://www.jsoftware.com/forums.htm

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