Asp Forum - comp.lang.fortran challenge

Bil Kleb

11/12/2007 1:28:00 AM

Having Ruby fun with the comp.lang.fortran folks:

http://tinyurl....
http://tinyurl....

Please riff a better Ruby answer...

Regards,
--
Bil Kleb
http://fun3d.lar...

13 Answers

Bil Kleb

11/12/2007 1:36:00 AM

Bil Kleb wrote:
> Having Ruby fun with the comp.lang.fortran folks:
>
> http://tinyurl....
> http://tinyurl....
>
> Please riff a better Ruby answer...

My current answer to the challenge...

require 'scanf'
require 'open-uri'

def write_uvs(u,v)
u = u[0...v.size] # limit U's size to V's
puts u, v # write Us & Vs
u.zip(v).each do |u_line,v_line| # zip Us & Vs together
u_value, v_value = u_line.scanf("%14c %f").last, v_line.scanf("%14c %f").last
printf "#{u_line[/.*=/].sub(/U/,'UV')} %7.3f\n", u_value*v_value # write UV
end
end

u, v = [], [] # initialize U & V arrays

open 'http://home.earthlink.net/~dave_gemini/de... do |iostream|
iostream.each_line do |line|
case line
when /^time/ then # found time delimiter
write_uvs(u,v) and u.clear and v.clear
puts "\n" + line.sub( /time\s*:/, 'for time' ) + "\n" # write time
when /^U/ then # add to U array
u << line
when /^V/ then # add to V array
v << line unless v.size == u.size # limit V's size to U's
end
end
end

write_uvs(u,v)

Later,
--
Bil Kleb
http://tufte-latex.goog...

M. Edward (Ed) Borasky

11/12/2007 2:58:00 AM

Bil Kleb wrote:
[snip]

Yeah ... it wasn't clear to me than anyone had set what the limits were.
If the code only has to deal with little chunks of data like

====================
time: 00 minutes
====================
velocity U in m/s

U ( 1, 1, 1) = 12.34
U ( 1, 1, 2) = 10.00
U ( 1, 1, 3) = 11.01
U ( 1, 2, 1) = 10.05
U ( 1, 2, 2) = 12.40
U ( 1, 2, 3) = 11.20
U ( 1, 3, 1) = 12.80
U ( 1, 3, 2) = 10.30
U ( 1, 3, 3) = 11.25

velocity V in m/s

V ( 1, 1, 1) = 11.40
V ( 1, 1, 2) = 12.00
V ( 1, 1, 3) = 13.50
V ( 1, 2, 1) = 11.00
V ( 1, 2, 2) = 11.70
V ( 1, 2, 3) = 11.25
V ( 1, 3, 1) = 11.50
V ( 1, 3, 2) = 10.60
V ( 1, 3, 3) = 11.23

"little" being defined as nine U values and nine V values per time step,
I don't see why one would do this in awk or Ruby when Fortran could do
it. It's been about 18 years since I read or wrote any Fortran, but I
didn't know awk at the time and so, presented with a problem like this,
would have coded it in Fortran. I think the real challenge here in any
language is to scale this up to way more than nine U and V values per
time step -- something where you'd actually need some kind of efficient
data structure. :)

Aaron Patterson

11/12/2007 3:21:00 AM

On Mon, Nov 12, 2007 at 10:30:06AM +0900, Bil Kleb wrote:
> Having Ruby fun with the comp.lang.fortran folks:
>
> http://tinyurl....
> http://tinyurl....
>
> Please riff a better Ruby answer...

I'm confused as to why the data needs to be retained in memory..... But
here is a little something I put together. It does maintain the
datastructures in memory before calculating the results.

require 'open-uri'

class PhilCollins
attr_writer :time
alias :time :time=

def initialize(io)
@uv_by_t = Hash.new { |h,t| h[t] = Hash.new { |n,a| n[a] = [] } }
@time = 10
io.each_line do |line|
line.gsub!(/:\s*(\d+)[^\d]*$/, '(\1)')
line.gsub!(/([UV])\s*$([^)]*)$\s=\s(.*)$/, '\1[[\2]] << \3')
line.downcase!
begin; instance_eval(line); rescue Exception; end
end
end

def u; @uv_by_t[@time]; end
alias :v :u

def inspect
@uv_by_t.sort_by { |t,v| t }.map { |t,v|
"for time: #{t}\n" +
v.map { |args,vals|
"UV(#{args.join(',')}) = #{vals[0] * vals[1]}" if vals.length == 2
}.compact.join("\n")
}.join("\n\n")
end
end

p PhilCollins.new(open('http://home.earthlink.net/~dave_gemini/de...))

PS, don't try this script at home! It's very dangerous! :-D

--
Aaron Patterson
http://tenderlovem...

Aaron Patterson

11/12/2007 3:24:00 AM

On Mon, Nov 12, 2007 at 12:20:32PM +0900, Aaron Patterson wrote:
> On Mon, Nov 12, 2007 at 10:30:06AM +0900, Bil Kleb wrote:
> > Having Ruby fun with the comp.lang.fortran folks:
> >
> > http://tinyurl....
> > http://tinyurl....
> >
> > Please riff a better Ruby answer...
>
> I'm confused as to why the data needs to be retained in memory..... But
> here is a little something I put together. It does maintain the
> datastructures in memory before calculating the results.
>
> require 'open-uri'
>
> class PhilCollins
> attr_writer :time
> alias :time :time=
>
> def initialize(io)
> @uv_by_t = Hash.new { |h,t| h[t] = Hash.new { |n,a| n[a] = [] } }
> @time = 10

Oops. @time should be nil, but that shouldn't change the output....

--
Aaron Patterson
http://tenderlovem...

James Gray

11/12/2007 1:57:00 PM

On Nov 11, 2007, at 7:30 PM, Bil Kleb wrote:

> Having Ruby fun with the comp.lang.fortran folks:
>
> http://tinyurl....
> http://tinyurl....
>
> Please riff a better Ruby answer...

That little challenge made me wish for some Ruby 1.9 elements, like
an ordered Hash.

James Edward Gray II

#!/usr/bin/env ruby -wKU

us, vs = Array.new, Array.new
DATA.each do |line|
if line =~ /^time\s*:\s*(.+?)\s*$/
[us, vs].each { |array| array.clear }
puts "for time #{$1}"
puts
elsif line =~ /^([UV])(\s*$[^)]+$)\s*=\s*([\d.]+)\s*$/
($1 == "U" ? us : vs) << [$2, $3.to_f]
puts line
end

if line =~ /^\s*$/ or DATA.eof?
next if us.empty? or vs.empty?
us.each do |sig, value|
next unless v = vs.assoc(sig)
puts "UV%s = %.2f" % [sig, value * v.last]
end
puts
end
end

__END__
====================
time: 00 minutes
====================
velocity U in m/s

U ( 1, 1, 1) = 12.34
U ( 1, 1, 2) = 10.00
U ( 1, 1, 3) = 11.01
U ( 1, 2, 1) = 10.05
U ( 1, 2, 2) = 12.40
U ( 1, 2, 3) = 11.20
U ( 1, 3, 1) = 12.80
U ( 1, 3, 2) = 10.30
U ( 1, 3, 3) = 11.25

velocity V in m/s

V ( 1, 1, 1) = 11.40
V ( 1, 1, 2) = 12.00
V ( 1, 1, 3) = 13.50
V ( 1, 2, 1) = 11.00
V ( 1, 2, 2) = 11.70
V ( 1, 2, 3) = 11.25
V ( 1, 3, 1) = 11.50
V ( 1, 3, 2) = 10.60
V ( 1, 3, 3) = 11.23

====================
time : 30 minutes
====================
velocity U in m/s

U ( 1, 1, 1) = 13.30
U ( 1, 1, 2) = 11.00
U ( 1, 1, 3) = 11.30
U ( 1, 2, 1) = 10.00
U ( 1, 2, 2) = 12.30
U ( 1, 2, 3) = 10.10
U ( 1, 3, 1) = 10.90
U ( 1, 3, 2) = 11.40
U ( 1, 3, 3) = 11.75

velocity V in m/s

V ( 1, 1, 1) = 12.40
V ( 1, 1, 2) = 11.00
V ( 1, 1, 3) = 11.60
V ( 1, 2, 1) = 11.20
V ( 1, 2, 2) = 11.90
V ( 1, 2, 3) = 11.35
V ( 1, 3, 1) = 12.50
V ( 1, 3, 2) = 11.60
V ( 1, 3, 3) = 13.20

Bil Kleb

11/12/2007 2:07:00 PM

James Edward Gray II wrote:
>
> That little challenge made me wish for some Ruby 1.9 elements, like
> an ordered Hash.

Nice; can it handle the

require 'open-uri'
open 'http://home.earthlink.net/~dave_gemini/de...

data which has some unequal (u,v) sets? -- see the 19th
post in http://tinyurl....

Later,
--
Bil

James Gray

11/12/2007 2:19:00 PM

On Nov 12, 2007, at 8:10 AM, Bil Kleb wrote:

> James Edward Gray II wrote:
>> That little challenge made me wish for some Ruby 1.9 elements,
>> like an ordered Hash.
>
> Nice; can it handle the
>
> require 'open-uri'
> open 'http://home.earthlink.net/~dave_gemini/de...
>
> data which has some unequal (u,v) sets?

Sure can. Try it out.

James Edward Gray II

Bil Kleb

11/13/2007 1:09:00 AM

James Edward Gray II wrote:
> On Nov 12, 2007, at 8:10 AM, Bil Kleb wrote:
>> Nice; can it handle the data which has some unequal (u,v) sets?
>
> Sure can. Try it out.

Sure enough. Why didn't you use a case? E.g.,

require 'open-uri'
us, vs = Array.new, Array.new
open 'http://home.earthlink.net/~dave_gemini/de... do |ios|
ios.each_line do |line|
case line
when /time\s*:\s*(.*)/ then # output time
puts "for time #{$1}"
puts
when /(U|V)(.*?)\s*=\s*([\d.]+)/ then # capture and echo U & V lines
($1 == "U" ? us : vs) << [ $2, $3.to_f ]
puts line
when /^\s*$/, ios.eof? then # output UVs and reset U & V arrays
next if us.empty? or vs.empty?
us.each do |coordinates, u|
next unless v = vs.assoc(coordinates)
puts "UV%s = %7.3f" % [coordinates, u * v.last]
end
puts
[us, vs].each { |array| array.clear }
end
end
end

Later,
--
Bil Kleb
http://fun3d.lar...

Bil Kleb

11/13/2007 1:15:00 AM

Aaron Patterson wrote:
> I'm confused as to why the data needs to be retained in memory..... But
> here is a little something I put together. It does maintain the
> datastructures in memory before calculating the results.

No prize for Phil, he didn't tweak the time output line
or echo the U and V lines... ;)

Later,
--
Bil Kleb
http://fun3d.lar...

James Gray

11/13/2007 1:24:00 AM

On Nov 12, 2007, at 7:11 PM, Bil Kleb wrote:

> James Edward Gray II wrote:
>> On Nov 12, 2007, at 8:10 AM, Bil Kleb wrote:
>>> Nice; can it handle the data which has some unequal (u,v) sets?
>> Sure can. Try it out.
>
> Sure enough. Why didn't you use a case? E.g.,

Well, I don't think it's the same. Is it?

> case line

> when /^\s*$/, ios.eof? then # output UVs and reset U & V arrays

Won't that check if the contents of line match the Regexp or if the
contents of line match the true/false returned by eof?(). That's not
what we want.

James Edward Gray II

comp.lang.ruby

comp.lang.fortran challenge

Bil Kleb

Bil Kleb

M. Edward (Ed) Borasky

Aaron Patterson

Aaron Patterson

James Gray

Bil Kleb

James Gray

Bil Kleb

Bil Kleb

James Gray

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