Optimization Tips

Re: Optimization Tips

Postby Jim » Wed Mar 17, 2010 2:39 pm

That's showing a for loop in the c language.
0
Hi

Jim 
Global Moderator
 

Re: Optimization Tips

Postby thomthom » Wed Mar 17, 2010 2:45 pm

That's what it's doing under the hood.
0
Thomas Thomassen — SketchUp Monkey & Coding addict
List of my plugins and link to the CookieWare fund
User avatar
thomthom 
PluginStore Author
PluginStore Author
 

Re: Optimization Tips

Postby Jim » Wed Mar 17, 2010 3:08 pm

thomthom wrote:That's what it's doing under the hood.


Right, so where is the definition for the for function?

The answer is there isn't one because for is not a function, but is "sugar". The for loop in Ruby really uses the .each method behind the scenes.

Although, I can't recall where I learned that. The link to the blog article mentions it, though.
0
Hi

Jim 
Global Moderator
 

Re: Optimization Tips

Postby tbd » Wed Mar 17, 2010 3:24 pm

speaking of each vs for :

Code: Select all
loop1 = []
loop2 = []

calls = ["one", "two", "three"]

calls.each do |c|
  loop1 << Proc.new { puts c }
end

for c in calls
  loop2 << Proc.new { puts c }
end

loop1[1].call #=> "two"
loop2[1].call #=> "three"
0
SketchUp Ruby Consultant | Podium 1.x developer
http://plugins.ro
User avatar
tbd 
 

Re: FOR .. IN

Postby Dan Rathbun » Wed Mar 17, 2010 3:25 pm

Jim wrote: The for loop in Ruby really uses the .each method behind the scenes. ... Although, I can't recall where I learned that.

'Pick-Axe' > For ... In expressions
0
    I'm not here much anymore. But a PM will fire email notifications.
    User avatar
    Dan Rathbun 
    PluginStore Author
    PluginStore Author
     

    Re: Optimization Tips

    Postby Jim » Wed Mar 17, 2010 3:28 pm

    I guess to get back on topic, for loops are not faster then .each iterators. The performance must have to do with how the for loop variables are not loop scoped, as in each.
    0
    Hi

    Jim 
    Global Moderator
     

    Re: Optimization Tips

    Postby thomthom » Sun Mar 21, 2010 8:32 pm

    Came across this link:
    http://www.h3rald.com/articles/efficien ... ut-review/

    On that list it says
    Use parallel assignment (a, b = 5, 6) where applicable

    while at this link:
    http://www.hxa.name/articles/content/ru ... _2007.html
    Avoid parallel assignment

    :roll:
    0
    Thomas Thomassen — SketchUp Monkey & Coding addict
    List of my plugins and link to the CookieWare fund
    User avatar
    thomthom 
    PluginStore Author
    PluginStore Author
     

    Re: Optimization Tips

    Postby thomthom » Sun Mar 21, 2010 10:55 pm

    thomthom wrote:Came across this link:
    http://www.h3rald.com/articles/efficien ... ut-review/

    On that list it says
    Use parallel assignment (a, b = 5, 6) where applicable

    while at this link:
    http://www.hxa.name/articles/content/ru ... _2007.html
    Avoid parallel assignment

    :roll:

    I just bought the ebook and that review summary was wrong - parallel assignments are not recommended for performance important tasks.
    Interesting read that book btw.
    0
    Thomas Thomassen — SketchUp Monkey & Coding addict
    List of my plugins and link to the CookieWare fund
    User avatar
    thomthom 
    PluginStore Author
    PluginStore Author
     

    Re: Optimization Tips

    Postby MartinRinehart » Thu Apr 01, 2010 3:06 pm

    Let's see - for performance I'm going to avoid iterations, arrays, hashes and objects.

    What's left?
    0
    Author, Edges to Rubies - The Complete SketchUp Tutorial at http://www.MartinRinehart.com/models/tutorial.

    MartinRinehart 
     

    Re: Optimization Tips

    Postby thomthom » Thu Apr 01, 2010 3:27 pm

    MartinRinehart wrote:What's left?


    puts "Hello World" :D
    0
    Thomas Thomassen — SketchUp Monkey & Coding addict
    List of my plugins and link to the CookieWare fund
    User avatar
    thomthom 
    PluginStore Author
    PluginStore Author
     

    Re: Optimization Tips

    Postby AdamB » Fri Apr 02, 2010 6:47 pm

    Jim wrote:I guess to get back on topic, for loops are not faster then .each iterators. The performance must have to do with how the for loop variables are not loop scoped, as in each.


    "Your racing car is not faster than my Trabant, it just covers more ground in a shorter time than my car." :-)
    0
    Developer of LightUp Click for website
    User avatar
    AdamB 
    LightUp Support
    LightUp Support
     

    Re: Optimization Tips

    Postby cjthompson » Wed Apr 07, 2010 9:29 pm

    Has anyone looked into Enumerable.grep()? it seems pretty useful, but I don't know how fast it is.
    0

    cjthompson 
     

    Re: Optimization Tips

    Postby Jim » Wed Apr 07, 2010 9:57 pm

    AdamB wrote:
    Jim wrote:I guess to get back on topic, for loops are not faster then .each iterators. The performance must have to do with how the for loop variables are not loop scoped, as in each.


    "Your racing car is not faster than my Trabant, it just covers more ground in a shorter time than my car." :-)


    Heh? Oh. Yes, I see. :oops:

    Would it be correct to say: An each loop can be as fast as a for loop if the loop variable has been initialized?
    0
    Hi

    Jim 
    Global Moderator
     

    Re: Optimization Tips

    Postby thomthom » Wed Apr 07, 2010 10:02 pm

    That would mean it's not the each loop itself that's slow - but the creation of variables.
    0
    Thomas Thomassen — SketchUp Monkey & Coding addict
    List of my plugins and link to the CookieWare fund
    User avatar
    thomthom 
    PluginStore Author
    PluginStore Author
     

    Re: Optimization Tips

    Postby Jim » Wed Apr 07, 2010 10:04 pm

    0
    Hi

    Jim 
    Global Moderator
     

    Re: Optimization Tips

    Postby thomthom » Sun Apr 11, 2010 8:44 pm

    Vertex.position is slow! Cache the result if you need to use the same Point3d multiple times.

    Point3d.distance also accepts Vertex objects in place of Point3d or Array.
    point1.distance(vertex2) is faster than point1.distance(vertex2.position).

    http://www.thomthom.net/blog/2010/04/sk ... rformance/
    0
    Thomas Thomassen — SketchUp Monkey & Coding addict
    List of my plugins and link to the CookieWare fund
    User avatar
    thomthom 
    PluginStore Author
    PluginStore Author
     

    Re: Optimization Tips

    Postby AdamB » Tue Apr 13, 2010 9:32 am

    Its all interesting info you're digging up thomthom, but I wonder where you're going..

    Ruby is a scripting language that makes for very quick development, modern constructs and good readability. So you pay for that with execution performance. However, performance with a big P which may include how fast you can complete and deliver functionality may be better - but once again I do think you should play to Ruby's strength rather than perhaps bend it into something it isn't.

    By the time you've created local copies of state, rewritten everything using a compact form etc etc you end up with something that is less readable and probably more prone to bugs. And as you've discovered, there is a massive difference in performance between native code and Ruby - such a large gulf, you're never going to come even close to closing it.

    You should do heavy lifting with a C extension and GUI / API / semantic stuff with Ruby. Processing geometry topology with Ruby is, in general, not practical. Not that it can't be done..but that's not what I'm suggesting.
    0
    Developer of LightUp Click for website
    User avatar
    AdamB 
    LightUp Support
    LightUp Support
     

    Re: Optimization Tips

    Postby thomthom » Tue Apr 13, 2010 9:54 am

    AdamB wrote:Its all interesting info you're digging up thomthom, but I wonder where you're going..

    That was actually stuff I found out before I got around to do a C extension.
    Jumping from Ruby - or any other scripting language - C extensions is not an easy jump. If C isn't your cup of tea then it's worth knowing what saves time in Ruby. Most plugin writers here doesn't do C and have no interest in it either. Just making something that work - but still one can save noticeable time.

    What I found most interesting in those test was that Vertex is a valid argument where the manual claims only Point3d. And passing the Vertex is faster than Vertex.position.


    As for C extensions - it appear that there's a significant overhead of converting VALUEs to workable C types - so if you iterate only once over a set of data there isn't much to gain. Only if there's quite a bit more calculations.
    0
    Thomas Thomassen — SketchUp Monkey & Coding addict
    List of my plugins and link to the CookieWare fund
    User avatar
    thomthom 
    PluginStore Author
    PluginStore Author
     

    Re: Optimization Tips

    Postby AdamB » Tue Apr 13, 2010 11:54 am

    thomthom wrote:As for C extensions - it appear that there's a significant overhead of converting VALUEs to workable C types - so if you iterate only once over a set of data there isn't much to gain. Only if there's quite a bit more calculations.

    Not really. You asked the wrong question, so you perhaps got an answer that has misled you.

    You asked about converting Ruby arrays to C etc. And everything I said stands. However, sounds like you actually want a C extension that operates upon the Ruby structures. If you have a situation where you are just wanting to twiddle existing Ruby data from C, it is well worth doing even for 1 pass because the fixed costs are pretty much zero.
    0
    Developer of LightUp Click for website
    User avatar
    AdamB 
    LightUp Support
    LightUp Support
     

    Re: Optimization Tips

    Postby thomthom » Tue Apr 13, 2010 12:40 pm

    I'm very green to this Ruby <-> C interaction - so its very likely I'm not doing thing the right way around.

    AdamB wrote:However, sounds like you actually want a C extension that operates upon the Ruby structures.

    What I have done so far is to calculate the soft selection for my Vertex Edit. So for each vertex in the selection set I needed to find the closest closest distance to any of the vertices not selected. It was the distance method that was so slow.
    I did some tests - created a dummy set of 3d data in C and calculated the soft selection for that. Very fast. But as soon as I made the source data set come from RUBY it became very slow. The C function was setting two sets of ruby arrays of vertices. Getting the X,Y,Z data for each vertex seemed to be very slow - converting Vertex to Point3d and then converting the X,Y,Z into C doubles.
    For every vertex in the selection I was iterating the remaining set of vertices and converting them.
    What I then did was to do a pre-pass of the non-selected vertices and create an C array of point3d structs. I then got a big speed increase. That's what lead me to the impression that converting Ruby VALUES to C types are expensive.
    0
    Thomas Thomassen — SketchUp Monkey & Coding addict
    List of my plugins and link to the CookieWare fund
    User avatar
    thomthom 
    PluginStore Author
    PluginStore Author
     

    Re: Optimization Tips

    Postby AdamB » Tue Apr 13, 2010 3:46 pm

    distance requires a square root of a scalar product. ie sqrt(A.B)

    Keep in mind that in native "cpu" math, A.B is perhaps ~5 cycles and sqrt(X) is perhaps ~35 cycles. If you don't actually need the squareroot but just need to find the closest, then just compare A.B which should be significantly faster.
    0
    Developer of LightUp Click for website
    User avatar
    AdamB 
    LightUp Support
    LightUp Support
     

    Re: Optimization Tips

    Postby thomthom » Tue Apr 13, 2010 4:16 pm

    AdamB wrote:distance requires a square root of a scalar product. ie sqrt(A.B)

    Keep in mind that in native "cpu" math, A.B is perhaps ~5 cycles and sqrt(X) is perhaps ~35 cycles. If you don't actually need the squareroot but just need to find the closest, then just compare A.B which should be significantly faster.

    Yes - I was reading up on sqrt and found that to compare "longer" and "shorter" I didn't need sqrt. So I changed my code to only do the square root after I've found the shortest distance. That way it's called only once per vertex in Selection. (I needed the distance for some other calculations)
    0
    Thomas Thomassen — SketchUp Monkey & Coding addict
    List of my plugins and link to the CookieWare fund
    User avatar
    thomthom 
    PluginStore Author
    PluginStore Author
     

    Re: Optimization Tips

    Postby cjthompson » Tue Apr 13, 2010 4:50 pm

    cjthompson wrote:Has anyone looked into Enumerable.grep()? it seems pretty useful, but I don't know how fast it is.


    well, since no one seems to be listening... :cry:
    I ran my own test (for: is using a for loop, grep: is using Enumerable.grep)
    speedTest
    for: entities - 0.016
    grep: entities - 0.015
    for: entities array - 0.0
    grep: entities array - 0.016
    for: range - 0.219
    grep: range - 0.203
    for: range array - 0.219
    grep: range array - 0.218
    for: strings - 0.469
    grep: strings - 0.234
    nil


    here is the code I used:
    Code: Select all
    def speedTest
       entities = Sketchup.active_model.entities
       entitiesArray = entities.to_a
       range = 0..1000000
       rangeArray = range.to_a
       strings = range.collect{|number| number.to_s}
       
       ## Entities
       
       results = []
       start = Time.now
       for ent in entities
          if(ent.class == Sketchup::Edge)
             results << ent
          end
       end
       puts "for: entities - " + (Time.now - start).to_s
       
       results = []
       start = Time.now
       results = entities.grep(Sketchup::Edge)
       puts "grep: entities - " + (Time.now - start).to_s
       
       ## Entities array
       
       results = []
       start = Time.now
       for ent in entitiesArray
          if(ent.class == Sketchup::Edge)
             results << ent
          end
       end
       puts "for: entities array - " + (Time.now - start).to_s
       
       results = []
       start = Time.now
       results = entitiesArray.grep(Sketchup::Edge)
       puts "grep: entities array - " + (Time.now - start).to_s
       
       ## Range
       
       results = []
       start = Time.now
       for num in range
          if(num == 318256)
             results << num
          end
       end
       puts "for: range - " + (Time.now - start).to_s
       
       results = []
       start = Time.now
       results = range.grep(318256)
       puts "grep: range - " + (Time.now - start).to_s
       
       ## Range Array
       
       results = []
       start = Time.now
       for num in rangeArray
          if(num == 318256)
             results << num
          end
       end
       puts "for: range array - " + (Time.now - start).to_s
       
       results = []
       start = Time.now
       results = rangeArray.grep(318256)
       puts "grep: range array - " + (Time.now - start).to_s
       
       ## Strings
       
       results = []
       start = Time.now
       for str in strings
          if(str.match(/312\Z/))
             results << str
          end
       end
       puts "for: strings - " + (Time.now - start).to_s
       
       results = []
       start = Time.now
       results = range.grep(/312\Z/)
       puts "grep: strings - " + (Time.now - start).to_s
       
    end


    and the model I tested on:
    0

    cjthompson 
     

    Re: Optimization Tips

    Postby thomthom » Tue Apr 13, 2010 4:54 pm

    I also read that depending on the settings of the compiler the instruction set used to compute sqrt and it's performance vary greatly. One of the articles I read suggested that many compilers will use old set of instructions by default for greater compatibility.
    What do you do for your projects?

    Edit: one of the articles I read: http://assemblyrequired.crashworks.org/ ... uare-root/
    0
    Thomas Thomassen — SketchUp Monkey & Coding addict
    List of my plugins and link to the CookieWare fund
    User avatar
    thomthom 
    PluginStore Author
    PluginStore Author
     

    Re: Optimization Tips

    Postby Pout » Mon Apr 19, 2010 2:32 pm

    concerning typename vs class:

    For, till now, unexplained reason when i change typename with class the results are different
    Script is a bit like this:

    Code: Select all
    x=entity.class (or entity.typename)
    if x=="Face"
    do something
    elsif x=="Group"
    do something
    elsif x=="ComponentInstance"
    do something
    else
    end


    When the type is "ComponentInstance" the results are not the same for class and typename.
    I need to check on this since the speed increase is huge
    0

    Pout 
     

    Re: Optimization Tips

    Postby thomthom » Mon Apr 19, 2010 2:52 pm

    .class returns a Class object - not a string.
    What causes the slow down is the string comparison - that's what you want to avoid.

    Code: Select all
    x=entity.class
    if x==Sketchup::Face
      do something
    elsif x==Sketchup::Group
      do something
    elsif x==Sketchup::ComponentInstance
      do something
    else
    end


    or

    Code: Select all
    if entity.is_a?(Sketchup::Face)
      do something
    elsif entity.is_a?(Sketchup::Group)
      do something
    elsif entity.is_a?(Sketchup::ComponentInstance)
      do something
    else
    end


    Update: fixed is_? to is_a?
    0
    Thomas Thomassen — SketchUp Monkey & Coding addict
    List of my plugins and link to the CookieWare fund
    User avatar
    thomthom 
    PluginStore Author
    PluginStore Author
     

    Re: Optimization Tips

    Postby Pout » Mon Apr 19, 2010 3:02 pm

    I'll check and let you know. When i use 'class' the correct conditions are entered but the result differs.
    I'll keep you posted if it changes with your scripts.

    Thx
    0

    Pout 
     

    Re: Optimization Tips

    Postby Pout » Fri May 07, 2010 9:41 am

    all works, speeds increase is fine :)
    thx!
    0

    Pout 
     

    Re: Optimization Tips

    Postby thomthom » Fri May 07, 2010 9:50 am

    :thumb:
    0
    Thomas Thomassen — SketchUp Monkey & Coding addict
    List of my plugins and link to the CookieWare fund
    User avatar
    thomthom 
    PluginStore Author
    PluginStore Author
     

    Re: Optimization Tips

    Postby kwalkerman » Thu Jul 15, 2010 6:29 am

    One thing I have noticed is that some code runs much slower with the outliner window open. Is there a way to close the window at the start of certain code execution, and then re-open it at the end?

    --
    Karen
    0

    kwalkerman 
     

    SketchUcation One-Liner Adverts

    by Ad Machine » 5 minutes ago



    Ad Machine 
    Robot
     

    PreviousNext


     

    Return to Developers' Forum

    Who is online

    Users browsing this forum: No registered users and 1 guest

    Visit our sponsors: