From: ara.t.howard@...
Date: 2006-05-25T14:55:34+09:00
Subject: Re: Marshaling NArray objects.

On Thu, 25 May 2006, Alex Polite wrote:

> On 5/25/06, Joel VanderWerf <vjoel@path.berkeley.edu> wrote:
>>   def marshal_load(ary)
>>     p ary
>>     @x, @y = ary # <-- populate self with persisted data
>>   end
>
>> 
>> Is there a NArray method like Array#replace ? That would probably do the
>> trick, if you called it in marshal_load with the narray as its argument.
>> 
>
> There doesn't seem to be anything like replace in narray. Maybe I
> should resort to using a wrapper class around my narrays?
>
> class NArrayWrapper
> def initialize(narray)
>    @narray = narray
> end
>
>  def marshal_dump
>     @narray.to_a
>  end
>
>  def marshal_load(array)
>    @narray = NArray.to_narray(array)
>  end
> end
>
> But then I'd have to write a whole bunch of accessor methods and stuff.
> I bet there's some C/ruby/narray wizardry that will replicate replace.

are you sure need it?  you can write/read narrays from file quite easily:


     harp:~ > cat a.rb
     require 'narray'

     na = NArray.int 2, 3

     na[0, true] = 42

     p na

     open('dat', 'w'){|f| f.write na.to_s}

     buf = IO.read('dat')

     na = NArray.to_na buf, NArray::INT, 2, 3

     p na


     harp:~ > ruby a.rb
     NArray.int(2,3):
     [ [ 42, 0 ],
       [ 42, 0 ],
       [ 42, 0 ] ]
     NArray.int(2,3):
     [ [ 42, 0 ],
       [ 42, 0 ],
       [ 42, 0 ] ]


so, assuming that you do, it's easy enough:

     harp:~ > cat a.rb
     require 'narray'

     class NArray
       def _dump *ignored
         Marshal.dump :typecode => typecode, :shape => shape, :data => to_s
       end
       def self._load buf
         h = Marshal.load buf
         typecode = h[:typecode]
         shape = h[:shape]
         data = h[:data]
         to_na data, typecode, *shape
       end
     end

     na = NArray.int 2, 3

     na[0, true] = 42

     dumped = Marshal.dump na

     na = Marshal.load dumped

     p na



     harp:~ > ruby a.rb
     NArray.int(2,3):
     [ [ 42, 0 ],
       [ 42, 0 ],
       [ 42, 0 ] ]


regards.


-a
-- 
be kind whenever possible... it is always possible.
- h.h. the 14th dali lama