First TC Lispers Meeting A Success June 12th, 2009
Patrick Stein

The first meeting of the TC Lispers group was a big success, IMO. I was figuring on an attendance near 20. My estimate is that it was really right around 40. That left us a little cramped in the meeting room at the Cafe, but we managed. We also lost the room before the presentation portion of the meeting was completely done, so there wasn’t much time for mingling. Actually, there was apparently a patio where people mingled afterward. I didn’t see this and took off too early. Mea culpa.

The presentation at this first meeting was on NST (not an abbreviation or acronym, but a sound effect /unsst/) which is a testing framework for Common Lisp. John Maraist did the presentation. He was a lively presenter, definitely had a good grasp on some dark corners of Lisp (like exactly what’s involved in the underbelly of MOP). Being a Haskell hacker though, he had some strange opinion that Lisp would be better if only it had strong typing. Well, what can you do? I mean, it’s not like he kicks puppies, I suppose. 8^)

It was great to see so many Lispers at so many levels there. About six or seven folks worked at Honeywell at some point in the past. Apparently, Honeywell had lots of Lisp development at one point. Who knew? About six or seven folks (overlapping a bit with the previous group) currently work at SIFT. There were some University students, a University teacher, some Ruby folks who wanted to see what Lisp was all about, some Lisp hobbyists, some independent consultants, some folks who can get Lisp in under the radar in their jobs, and on and on.

The next meeting is going to be 6pm on Tuesday, July 14th at the Common Roots cafe on 26th and Lyndale in Minneapolis. The topic is not quite set yet, but it seems like it might be a series of short talks on introductory aspects of Lisp.

There’s much discussion going on on the mailing list about finding a bigger venue for August and onward. There’s much discussion about exact topics for next month’s meeting. If you’re able to make it to the Twin Cities on a Tuesday evening, mark your calendars and come on out.

(assert (>= tclispers-meeting +fun+))

Installing mpich2 for use with CL-MPI June 5th, 2009
Patrick Stein

Some time back, I began writing some OpenMPI wrappers for Lisp. I got everything that I needed working, but I hardly scratched the surface of what MPI-2 makes available.

Recently, Alex Fukunaga started up a blog about Lisp. One of the things he has done is make CFFI bindings for mpich2. Here is an introductory post about those bindings with a link to his CL-MPI site.

Today, I have been working on getting his bindings up and running under Ubuntu Linux and Mac OS X.

Read the rest of this entry ⇒

Emacs + Slime + SBCL on Windows Vista May 27th, 2009
Patrick Stein

I just finished setting up Windows Vista to run in VMWare Fusion. Then, I finally tackled setting up Emacs with Slime and SBCL under Windows Vista.

For the most part, I followed Robert Zubek’s gameplan. However, I quickly ran into a problem with swank’s temporary files not being in a writable location. I wish I had found this thread sooner. Alas, I ended up rolling my own by tweaking the temp-file-name function in swank-sbcl.lisp. The new version looks like this:

(defun temp-file-name ()
    "Return a temporary file name to compile strings into."
  #-win32 (concatenate 'string (tmpnam nil) ".lisp")
  #+win32 (concatenate 'string
                       (sb-ext:posix-getenv "TEMP")
                       "/"
                       (symbol-name (gensym "SL"))
                       ".lisp"))

Developing Lisp in Ubuntu Linux with VMWare Fusion May 27th, 2009
Patrick Stein

I am working on some lisp software that I would like to run under Linux, MacOSX, and Windows.

I have a PC that I can boot into either Ubuntu Linux or Windows Vista. Of course, I have a variety of services running under Ubuntu Linux on that box that the rest of my network would rather have around. As such, I would rather never boot that machine into Windows. So, I thought I’d give VMWare Fusion a try.

Actually, I thought I would try both VMWare Fusion and Parallels. Alas, Parallels lets me get my virtual machine set up, but will not let me run it without a license. VMWare Fusion lets me play for 30 days before buying a license. From what I’m seeing from VMWare Fusion’s performance, I can’t imagine dropping $80 on Parallels just to see if its virtual machine can outperform what I’m seeing from Fusion.

Right now, I am in the process of moving over the PC’s Windows stuff to my laptop so I can try running Vista through Fusion. While I was waiting for that, however, I installed Ubuntu under Fusion, updated a ton of packages, installed emacs, sbcl, slime, etc.

For comparison, I took some lisp code that runs in just under 11 seconds on my laptop. I ran the same code under Ubuntu in Fusion on the same laptop. It ran in just under 12 seconds. Some of that may also be that I am using an older version of SBCL under Ubuntu than I am native.

I have some more testing to do to make sure that cl-opengl will perform as well. But, I am quite pleased.

Optimizing Lisp May 24th, 2009
Patrick Stein

Paul Reiners recently posted some code to the TC Lispers mailing list. The code began from Paul Graham’s ANSI Common Lisp book. Exercise 13b has you adding declarations to some code so that the compiler can better take advantage of the types involved. Oddly, the code ran more slowly with his typing than it did without it. I had the same experience when I tried this code under SBCL 1.0.23 on Mac OS X.

Here is Paul’s original code which he made available with Creative Commons License the Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License.

I stripped out the declarations and started adding them in one by one, trying to deal with as many compiler notes as I could figure out in the process. First, in the base case, the following took 22.5 seconds on my computer.

(time (ray-test 8))

After much tweaking, I have gotten it down to just under 11 seconds. Most of that came with declaring the types of the slots in the (defstruct …)‘s and these three declarations:

(declaim (ftype (function (long-float) long-float) sq))
(declaim (ftype (function (long-float
                           long-float
                           long-float) long-float) mag))
(declaim (ftype (function (long-float
                           long-float
                           long-float)
                          (values long-float
                                  long-float
                                  long-float)) unit-vector))

This declaration, however, shot me back up to 22 seconds.

(declaim (ftype (function (long-float
                           long-float
                           long-float)
                          long-float)) minroot))

Of course, it really should have been returning (or long-float nil). But, that didn’t help either. From the compiler notes, it seems that (min …) in SBCL doesn’t deal well with unboxed floats. I will have to look harder at that section and ask on the SBCL lists. I believe that I tried decorating the expressions there, too.

(the long-float (min (the long-float
                       (/ (the long-float (+ (the long-float (- b))
                                             discrt)
                               (the long-float (* 2L0 a)))))
                     (the long-float
                       (/ (the long-float (- (the long-float (- b))
                                             discrt)
                               (the long-float (* 2L0 a)))))))

Updates In Email

Email:

RSS Feeds

l