Na_str-0.0.0 : combining narray with mmap for persistant num

NAME

na_str (c extension)

nmap (reference ruby class which combines narray and mmap)

URIS

http://codeforpeople.com/lib/ruby/na_str/

SYNOPSIS

na_str is designed to allow data sharing between narray object and
other ruby
objects. the shared data is that returned by the objects to_s or
to_str method
and rb_string_new4. using this technique memory mapped (using guy’s
mmap
extensions) data can be altered with no explicit io on the users part
and
partial changed to numerical grids can occur very quickly and
persistently.

the nmap.rb reference impl is a concrete example of this usage and is
included in the distribution

EXAMPLE USAGE

 jib:~/eg/ruby/na_str > cat a.rb
 #
 # the nmap extension is installed along with na_str
 #
   require 'nmap'
 #
 # the NMap ctor interface is similar to NArray's, but a backing 

file must also
# be specified
#
path, x, y = ‘int.data’, 3, 4
nmap = NMap.int path, x, y
#
# copy the last row to the first
#
nmap.na[true, 0] = nmap.na[true, 3]
#
# set the last row to be the current time. if you run this a few
times you’ll
# notice that changes to the narray are automatically written to
the to
# backing file via the magic of mmap
#
nmap.na[true, 3] = Time.now.to_i
#
# show the narray
#
p nmap.na

jib:~/eg/ruby/na_str > ruby a.rb
NArray(ref).int(3,4):
[ [ 0, 0, 0 ],
[ 0, 0, 0 ],
[ 0, 0, 0 ],
[ 1151439012, 1151439012, 1151439012 ] ]

jib:~/eg/ruby/na_str > ruby a.rb
NArray(ref).int(3,4):
[ [ 1151439012, 1151439012, 1151439012 ],
[ 0, 0, 0 ],
[ 0, 0, 0 ],
[ 1151439014, 1151439014, 1151439014 ] ]

SPEED

jib:~/eg/ruby/na_str > cat a.rb

reference impl installed with na_str

 require 'nmap'

setup a narray grid containing 1 gb of ints

 gb = 2 ** 30
 mb = 2 ** 20
 sizeof_int = [42].pack('i').size
 gig_of_ints = gb / sizeof_int
 nmap = NMap.int '1GB',  gig_of_ints

set about 1 million of the ints to 42

 nmap.na[0 .. mb] = 42

show that the data was written

 p nmap.na[mb - 1]

jib:~/eg/ruby/na_str > time ruby a.rb
42

real 0m0.078s
user 0m0.020s
sys 0m0.020s

jib:~/eg/ruby/na_str > ls -ltar 1GB
-rw-rw-r-- 1 ahoward ahoward 1073741824 Jun 27 14:28 1GB

this an experimental package - thank to matz for the tip on rb_str_new4.

enjoy.

-a

On 6/27/06, [email protected] [email protected] wrote:

this an experimental package - thank to matz for the tip on rb_str_new4.

enjoy.

Ara, for the uninitiated among us, could you please explain what
rb_str_new4 does exactly? Also, what is the ELTS_SHARED flag
signifies and in what circumstances should it be used?

Blessings,
TwP

Hi,

In message “Re: [ANN] na_str-0.0.0 : combining narray with mmap for
persistant numerical data”
on Thu, 29 Jun 2006 02:14:34 +0900, “Tim P.”
[email protected] writes:

|Ara, for the uninitiated among us, could you please explain what
|rb_str_new4 does exactly? Also, what is the ELTS_SHARED flag
|signifies and in what circumstances should it be used?

rb_str_new4() creates a new string that shares internal memory region
with the original. ELTS_SHARED means the string is sharing memory
region with other string object.

						matz.

On Fri, 30 Jun 2006, Joel VanderWerf wrote:

$ man nmap

nmap - Network exploration tool and security scanner

i open to suggestion - ideas? this first one was just a whack at it
anyhow -
but it’s already pretty useful.

cheers.

-a

[email protected] wrote:

NAME

na_str (c extension)

nmap (reference ruby class which combines narray and mmap)

This is very cool, but won’t the name be confusing?

$ man nmap

nmap - Network exploration tool and security scanner

On Fri, 30 Jun 2006, Joel VanderWerf wrote:

$ man nmap

nmap - Network exploration tool and security scanner

maybe na_map?

-a

[email protected] writes:

This is very cool, but won’t the name be confusing?

$ man nmap

nmap - Network exploration tool and security scanner

maybe na_map?

What about ActiveMMappedNArray? scnr.

On Sat, 1 Jul 2006, Christian N. wrote:

nmap (reference ruby class which combines narray and mmap)

What about ActiveMMappedNArray? scnr.

heh.

i’ll count that as na_map +1 then :wink:

-a

This forum is not affiliated to the Ruby language, Ruby on Rails framework, nor any Ruby applications discussed here.

| Privacy Policy | Terms of Service | Remote Ruby Jobs