Re: Multi-Dimensional Arrays in Priority Queues

Thanks.  This may do what I need.  I'll work with it and see if it is the
best way to go.

Being new to Ruby much of this is still magic to me.  I look forward to the
day when I'll move beyond the magic phase.

No Sam

On Mon, Sep 21, 2009 at 12:02 AM, Josh Cheek <[e-mail]> wrote:

> On Sun, Sep 20, 2009 at 10:23 PM, Mason Kelsey <[e-mail]
> >wrote:
>
> > Tried it but it didn't work.  Made the following change:
> >
> > require "pqueue"
> > pq=PQueue.new(proc{|x,y| x[0]<y[0]})
> > pq.push([[12], [123456780], [123456708]])
> > pq.push([[23], [123456780], [123456708]])
> > pq.push([[4], [123456780], [123456708]])
> > pq.push([[33], [123456780], [123456708]])
> > pq.push([[02], [123456780], [123456708]])
> > pq.push([[54], [123456780], [123456708]])
> > print "size:"+pq.size.to_s+"\n"
> > print "each_pop: "
> > pq.each_pop{|x| print x.to_s+" "}
> > print "\n"
> > I got the messages:
> > >ruby simple_pqueue.rb
> > simple_pqueue.rb:3: undefined local variable or method `x' for
> main:Object
> > (NameError)
> >  from ./pqueue.rb:24:in `[]'
> >  from ./pqueue.rb:24:in `upheap'
> >  from ./pqueue.rb:65:in `push'
> >  from simple_pqueue.rb:5
> > >Exit code: 1
> >
> > The "from" error messages appear to be coming from the code inside of the
> > pqueue class methods.
> >
> > Doesn't like the brackets.  I tried several variations of this and also
> got
> > a message that said the < is an invalid method.  Very strange.  Sorry but
> > I'm totally confused here.
> >
> > There must be a way to do this.
> >
> > No Sam
> >
> > On Sun, Sep 20, 2009 at 10:31 PM, Mario Camou <[e-mail]>
> > wrote:
> >
> > > Hi,
> > > In the line:
> > >
> > > pq.push([2], [123456780], [123456708])
> > >
> > > you're not passing in a multi-dimensional array, you're passing 3
> > > parameters
> > > each of which is an array. Try with:
> > >
> > > pq.push([[2], [123456780], [123456708]])
> > >
> > > (notice the double [ at the beginning and the  double ] at the end).
> > >
> > > you will also have to change your PQueue creation to something like
> this:
> > >
> > > pq=PQueue.new(proc{|x,y| x[0]<y[0]})
> > >
> > > Haven't tested this in irb but it (or something very much like it)
> should
> > > work.
> > >
> > > -Mario.
> > >
> > > --
> > > I want to change the world but they won't give me the source code.
> > >
> > >
> > > On Mon, Sep 21, 2009 at 04:25, Mason Kelsey <[e-mail]>
> > wrote:
> > >
> > > > In my program I need to construct a priority queue that sorts
> > ascending.
> > > > The basic idea can be expressed in the following simple code that
> uses
> > a
> > > > Priority Queue concept.  See:
> > > > http://www.math.kobe-u.ac.jp/~kodama/tips-ruby-pqueue.html<
> http://www.math.kobe-u.ac.jp/%7Ekodama/tips-ruby-pqueue.html<http://www.math.kobe-u.ac.jp/~kodama/tips-ruby-pqueue.html>
> >
>  > > >
> > > > 1   require "pqueue"
> > > > 2
> > > > 3   pq=PQueue.new(proc{|x,y| x<y})
> > > > 4   pq.push(2)
> > > > 5   pq.push(3)
> > > > 6   pq.push(4)
> > > > 7   pq.push(3)
> > > > 8   pq.push(2)
> > > > 9   pq.push(4)
> > > > 10 print "size:"+pq.size.to_s+"\n"
> > > > 11 print "each_pop: "
> > > > 12 pq.each_pop{|x| print x.to_s+" "}
> > > > 13 print "\n"
> > > >
> > > > This is clean and simple to understand.  But I need to be able to put
> > > into
> > > > the queue several components per push to make an entire record
> object.
> >  I
> > > > need to have three components: an integer heuristic value, followed
> by
> > > two
> > > > 9
> > > > digit configuration patterns, such as
> > > > pq.push([2], [123456780], [123456708])  But this gives me an argument
> > > error
> > > > message:
> > > > pqueue.rb:4:in `push': wrong number of arguments (3 for 1)
> > > > (ArgumentError) from pqueue.rb:4
> > > >
> > > > or pq.push(2_123456780_123456708) ignores the underscore separators
> and
> > > > runs
> > > > the 3 parts together as one long number.
> > > >
> > > > Still learning Ruby and none of the books address multiple
> dimensional
> > > > arrays very well.  Is the Priority Queue not able to handle
> > > > multi-dimensional arrays?  Can this code be modified to allow
> > > > multi-elements
> > > > in each push and still sort on the first element?
> > > >
> > > > If I cannot use pqueue, is there another required library of methods
> > that
> > > > will work with three elements in each array entry?
> > > >
> > > > Thanks in advance to those of you who can help.  And thanks to all
> who
> > > help
> > > > out on this forum.  Very good forum.
> > > >
> > > > No Sam
> > > >
> > >
> >
>
> require "pqueue"
> pq=PQueue.new proc{|x,y| x[0][0]<y[0][0]}
> pq.push([[12], [123456780], [123456708]])
> pq.push([[23], [123456780], [123456708]])
> pq.push([[4],  [123456780], [123456708]])
> pq.push([[33], [123456780], [123456708]])
> pq.push([[02], [123456780], [123456708]])
> pq.push([[54], [123456780], [123456708]])
> print "size:"+pq.size.to_s+"\n"
> print "each_pop: "
> pq.each_pop{|x| p x}
>
> __END__
> output that I got:
> size:6
> each_pop: [[2], [123456780], [123456708]]
> [[4], [123456780], [123456708]]
> [[12], [123456780], [123456708]]
> [[23], [123456780], [123456708]]
> [[33], [123456780], [123456708]]
> [[54], [123456780], [123456708]]
>
> You were passing a two dimensional array, so x[0] returns an array, ie [2]
> to get it to an integer, you need to go in one more time so x[0][0] would
> return 2, which is comparable to other integers.
>
> You should consider making a class to handle these objects.
>