[MWForum]MIA, Ask an Expert: gravity, asciis, ...

[Mike Sandy]

I used:
st resett repeat 100[repeat 1000[fd 0.00001]] show timer.

It is the REPEAT procedure which determines the time.
It doesn't matter whether you use  0.00001, 0.0001 or 0.001.
A single REPEAT will speed it up.

Mike


----- Original Message ----- 
From: "Jeff Knope" <jknope@asis.com>
To: <mwforum@lists.mathcats.com>
Sent: Sunday, October 10, 2004 6:16 PM
Subject: Re: [MWForum]MIA, Ask an Expert: gravity, asciis, ...


> Hi ~
>
> I've tried Mike's speed test and have uncovered some interesting things.
>
> My timing method is evidently more crude than Mike's: I wait 'til the
second
> hand on the wall clock strikes 12 and hit 'return' to start the command.
> When the large black dot indicating the command is running goes off, I
look
> quickly at the clock. I usually have to decide between, say 37 seconds or
38
> or maybe it was 39. Mike pinned it down to a tenth of a second, so he must
> be using a more sophisticated timing method.
>
> If others report findings, along with their processor speeds, we might be
> able to get a clearer idea of the effect of processor speed.
>
> To make a level playing field, it'd be a good idea to do things in a
> standardized way. I first issued a "home st recycle" before initiating the
> "repeat 100[repeat 1000[fd 0.0001]] command. Whether the turtle is shown
or
> hidden makes a real difference: about 12 seconds slower with "st"
>
> My processor is a P4 M, rated at 1.7 GHz, according to System Properties.
> (For some reason, it says "1.19 GHz" directly below the CPU speed
statement.
> I have no idea what that means.)
>
> My results using "st" are right at 55 seconds. About 38 sec. with "ht"
>
> It was my understanding that processors handle intergers much more
> efficiently than floating point values. To test this I tried the command
> "repeat 100[repeat 1000[fd 1]]. Using the integer was about 5 seconds
> faster.
>
> By far the most perplexing outcome was when I tried this test using EX
> instead of MWPro. In EX performance plummeted to 1:45 using "st" and 1:28
> with "ht." That's about twice as long. My EX is version 1.0.0.1. My MWPro
> doesn't show a version number, but all its .dll files are Version
11.0.0.0.
>
> I'd be very interested to track down what accounts for this. I've grown
very
> fond of EX (especially the dialog boxes and single-line text boxes, that
> improve program communication with the user enormously). But that
> performance difference is a steep price to pay. Maybe Shawn could comment
on
> this?
>
> --Jeff
>
>
> ----- Original Message ----- 
> From: "Mike Sandy" <mjsandy@btopenworld.com>
> To: <mwforum@lists.mathcats.com>
> Sent: Sunday, October 10, 2004 7:33 AM
> Subject: Re: [MWForum]MIA, Ask an Expert: gravity, asciis, ...
>
>
> > > I've been thinking about this. I believe that
> > > since the speed of computers increase exponentially
> > > fd.slow should use exponents too:
> >
> > Does the speed of a turtle, in fact,
> > increase exponentially with the computer
> > rating? I've no way of knowing.
> > It doesn't really matter, since it easy
> > to allow for the computer rating.
> >
> > I've found that a turtle will move
> > 1 unit given the instruction:
> >  repeat 100[repeat 1000[fd 0.00001]]
> > It takes 38.4 sec. at 1.1 GHz.
> > I would guess even at 3 GHz it is still
> > going to be very slow!
> >
> > I had to use nested repeats as the
> > maximum value of :n for repeat :n[...],
> > is 9999.
> >
> > So there is plenty of scope to control the turtle
> > speed.
> > One way to cover (most) computers would
> > be to introduce a factor, comp_f. (as a projectvar?),
> > or simply to use a value in the proc as decided by
> > experiment.
> >
> > to fd_slow :dist
> >  repeat :dist / speed * comp_f [fd speed / comp_f]
> > end
> >
> > speed - the speed of the turtle.
> >
> > On my machine, with slider range 1 - 20, comp_f = 50
> > might do.
> >
> > Mike
> >
> >
> > > Hi Mike,
> > >
> > > I've been thinking about this. I believe that
> > > since the speed of computers increase exponentially
> > > fd.slow should use exponents too:
> > >
> > >
> > > to fd.slow :dist
> > > let [val power 2 20 - speed]
> > > repeat :val [fd :dist / :val]
> > > end
> > >
> > > This works with a slider 0-20.
> >
> >
> >
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