Optimization Tips

thomthom

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.

AdamB

@thomthom said:

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.

thomthom

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

@adamb said:

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.

AdamB

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.

thomthom

@adamb said:

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)

cjthompson

@cjthompson said:

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...
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:

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:

test1k.skp

thomthom

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/2009/10/16/timing-square-root/

Pout

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:

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

thomthom

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


x=entity.class
if x==Sketchup;;Face
  do something
elsif x==Sketchup;;Group
  do something
elsif x==Sketchup;;ComponentInstance
  do something
else
end

or


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?

Pout

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

Pout

all works, speeds increase is fine
thx!

thomthom

kwalkerman

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

Dan Rathbun

@kwalkerman said:

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?

Maybe...
but have you tried using Model.start_operation ?

see also abort_operation and commit_operation

Dan Rathbun

UI.show_inspector "Outliner"
toggles it.
Shows it if it's closed
Rolls it up if it's shown
Unrolls it if it's rolled up

There's no way with the API to tell (now) what state it is in.

TIG

I think Jim made a Windows hack to toggle a rollup...

### toggleWindows.rb - based on Jim's ideas - only for Windows...
### 20090401 TIG
### needs "win32api.so"
if [PLATFORM].grep(/mswin/)==[PLATFORM] and Sketchup.find_support_file("Win32API.so","Plugins/")
### = a Windows machine
  require 'Win32API.so'
  def toggleRollUp(name)
    findWindow = Win32API.new("user32.dll","FindWindow",['P','P'],'N')
    pw=findWindow.call(0,name)
    sendMessage = Win32API.new("user32.dll","SendMessage",['N','N','N','P'],'N')
    sendMessage.call(pw,0x00a1,2,"")#WM_NCLBUTTONDOWN
    sendMessage.call(pw,0x0202,0,"")#WM_LBUTTONUP
  end
  def isRolledUp(name)
    findWindow = Win32API.new("user32.dll","FindWindow",['P','P'],'N')
    getWindowRect= Win32API.new("user32.dll","GetWindowRect",['P','PP'],'N')
    pw=findWindow.call(0,name)
    data=Array.new.fill(0.chr,0..4*4).join
    getWindowRect.call(pw,data);
    rect=data.unpack("i*")
    #if window height is less than 90 then the window is rolledup
    return (rect[3]-rect[1])<90
  end
end#if

You add 'Outliner' to run it... test if rolled up, toggle roll up if not etc etc........

Dan Rathbun

its nice but...
The windows have other language names in the loacalized versions.
The code needs updating. It needs to search by ID instead.
(Or have arrays of the Inspector captions in all the local versions.)

It also should be in the SKX forum, either as a UI module extended method (which would be half done, as it's only Win32,) or a SKX::GUI::WIN method.. or something

TIG

I only pass on Jim's hack... if you want to 'fix' it please do... It'd be better if the API had proper access to these anyway !

kwalkerman

Dan, this is absolutely what I need. It is the updating of the UI that is slowing the calculation down. Having the outliner window open compounds the problem.

--
Karen

thomthom

@kwalkerman said:

Dan, this is absolutely what I need. It is the updating of the UI that is slowing the calculation down. Having the outliner window open compounds the problem.

--
Karen

You are using .start_operation with the disable_ui flag, right?

Also, try to do as much as possible in bulk operations. Transform and erase in bulks. entities.erase_entities instead of entity.erase! etc.
Cache calculation results - Ruby is horribly slow in crunching numbers.
Often, methods that accepts Point3D objects can use Vertex objects as well - though the API docs doesn't mention this. If you are doing many iteration vertex.position will eat time. So try to feed the methods raw vertices instead.