gmane.comp.lang.racket.user

Bindings for libgsl (GNU Scientific Library)

Jens Axel Søgaard — 2012-05-24T19:21:50

Hi All.

I am attempting to get Noels bindings for libgsl working on my machine
(OS X 64 bit).
    https://github.com/noelwelsh/mzgsl

My problem is that it crashes DrRacket and I can't pinpoint where it happens.

I downloaded gsl using port with

    sudo port install gsl

This downloaded and installed version 1.15.

Now racket is able to find and load the libraries.
I can now allocated a gsl_vector with
    (gsl_vector-malloc n).

Allas calling gslvector-fill! aka gsl_vector_set_all will crash Racket.

The vector structure is defined as:

(define-cstruct _gsl_vector
  ([size   _size_t]
   [stride _size_t]
   [data   _pointer]
   [block  _pointer]
   [owner  _int]))

And the actual allocation functions as:

(define (gsl_vector-malloc n)
  (define ptr (malloc _double n 'raw))
  (define v (make-gsl_vector n 1 ptr #f 0))
  (register-finalizer v (lambda (_) (free ptr)))
  v)

Does this look right?

The actual source file is here:
https://github.com/noelwelsh/mzgsl/blob/master/low-level/gsl-vector.ss


The error message after a crash:

Process:         DrRacket [62009]
Path:            /Applications/Racket Full
v5.3.0.6/*/DrRacket.app/Contents/MacOS/DrRacket
Identifier:      org.racket-lang.DrRacket
Version:         5.3.0.6 (5.3.0.6)
Code Type:       X86-64 (Native)
Parent Process:  bash [62005]

Date/Time:       2012-05-24 20:56:26.374 +0200
OS Version:      Mac OS X 10.7.3 (11D50b)
Report Version:  9

Interval Since Last Report:          6884660 sec
Crashes Since Last Report:           77
Per-App Interval Since Last Report:  776847 sec
Per-App Crashes Since Last Report:   3
Anonymous UUID:                      479A6BDE-6BDF-47B6-AB0F-194A795E4C53

Crashed Thread:  0  Dispatch queue: com.apple.main-thread

Exception Type:  EXC_BAD_ACCESS (SIGSEGV)
Exception Codes: KERN_INVALID_ADDRESS at 0x0000000000000000

VM Regions Near 0:
-->
    __TEXT                 0000000100000000-0000000100008000 [   32K]
r-x/rwx SM=COW  /Applications/Racket Full
v5.3.0.6/DrRacket.app/Contents/MacOS/DrRacket

Application Specific Information:
objc[62009]: garbage collection is OFF

Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0   libgsl.dylib                  0x000000010d152460 gsl_vector_set_all + 32
1   Racket                        0x00000001002aee5c ffi_call_unix64 + 76
2   Racket                        0x00000001002afa74 ffi_call + 644
3   Racket                        0x00000001002a1c56 ffi_do_call + 1558
4   Racket                        0x0000000100062282 scheme_do_eval + 9058
5   Racket                        0x0000000100064fdc
_scheme_apply_multi_from_native + 108
6   ???                           0x00000001007e4078 0 + 4303241336
7   Racket                        0x0000000100061f19 scheme_do_eval + 8185
8   Racket                        0x00000001000640d5 splice_execute + 229
9   Racket                        0x000000010006111f scheme_do_eval + 4607
10  Racket                        0x0000000100076754 force_values + 292
11  Racket                        0x0000000100080452
scheme_force_value_same_mark + 114
12  ???                           0x00000001007cfdf7 0 + 4303158775
13  Racket                        0x0000000100061f19 scheme_do_eval + 8185
14  Racket                        0x00000001000822c9
scheme_finish_apply_for_prompt + 873
15  Racket                        0x000000010008249c
scheme_apply_for_prompt + 92
16  Racket                        0x000000010008e062 call_with_prompt + 1282
17  Racket                        0x00000001000650f9
_scheme_apply_multi_from_native + 393
18  ???                           0x00000001037e79b0 0 + 4353587632
19  ???                           0x00000001007d20fb 0 + 4303167739
20  ???                           0x00000001037e657c 0 + 4353582460
21  Racket                        0x0000000100061f19 scheme_do_eval + 8185
22  Racket                        0x00000001000822c9
scheme_finish_apply_for_prompt + 873
23  Racket                        0x000000010008249c
scheme_apply_for_prompt + 92
24  Racket                        0x000000010008e062 call_with_prompt + 1282
25  Racket                        0x00000001000650f9
_scheme_apply_multi_from_native + 393
26  ???                           0x00000001037e79b0 0 + 4353587632
27  ???                           0x00000001007c5264 0 + 4303114852
28  Racket                        0x0000000100064fdc
_scheme_apply_multi_from_native + 108
29  ???                           0x00000001037e699c 0 + 4353583516
30  Racket                        0x0000000100061f19 scheme_do_eval + 8185
31  Racket                        0x0000000100064fdc
_scheme_apply_multi_from_native + 108
32  ???                           0x00000001007cfee0 0 + 4303159008
33  Racket                        0x0000000100061f19 scheme_do_eval + 8185
34  Racket                        0x00000001000822c9
scheme_finish_apply_for_prompt + 873
35  Racket                        0x000000010008249c
scheme_apply_for_prompt + 92
36  Racket                        0x000000010008e062 call_with_prompt + 1282
37  ???                           0x00000001007c51f7 0 + 4303114743
38  Racket                        0x0000000100061f19 scheme_do_eval + 8185
39  Racket                        0x00000001000822c9
scheme_finish_apply_for_prompt + 873
40  Racket                        0x000000010008249c
scheme_apply_for_prompt + 92
41  Racket                        0x000000010008e062 call_with_prompt + 1282
42  ???                           0x00000001007d01e5 0 + 4303159781
43  ???                           0x00000001007c5264 0 + 4303114852
44  Racket                        0x0000000100076754 force_values + 292
45  Racket                        0x0000000100080452
scheme_force_value_same_mark + 114
46  ???                           0x00000001007cfc39 0 + 4303158329
47  Racket                        0x0000000100061f19 scheme_do_eval + 8185
48  Racket                        0x00000001000822c9
scheme_finish_apply_for_prompt + 873
49  Racket                        0x000000010008249c
scheme_apply_for_prompt + 92
50  Racket                        0x000000010008e062 call_with_prompt + 1282
51  ???                           0x00000001007d01e5 0 + 4303159781
52  Racket                        0x0000000100061f19 scheme_do_eval + 8185
53  Racket                        0x00000001000802d3 apply_k + 179
54  Racket                        0x0000000100080f86
scheme_top_level_do_worker + 1046
55  Racket                        0x0000000100280321 start_child + 1153
56  Racket                        0x000000010028467a make_subprocess + 570
57  Racket                        0x000000010028495e
scheme_thread_w_details + 446
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Re: Rationale behind missing string-trim

Eli Barzilay — 2012-05-24T18:19:34

Note that this doesn't work right:

  -> (string-trim-both "  str ing  ")
  "str"



Sidenote: `string-trim', and several additional simplified string
functions is now in the repository and will be included in the next
release.

Re: Finite State Machines of Arbitrary Size using Racket's composable control

Galler — 2012-05-24T18:15:34

So am I eligible for some kind of reinventing the wheel award at Rackcon 
2012?


On Thu, May 24, 2012 at 1:53 PM, Eli Barzilay wrote:

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Re: Finite State Machines of Arbitrary Size using Racket's composable control

Eli Barzilay — 2012-05-24T17:53:57

A relevant side-comment is that this is a popular way for implementing
tail-calls:

  http://en.wikipedia.org/wiki/Tail_call#Through_trampolining



20 minutes ago, Galler wrote:

Re: Finite State Machines of Arbitrary Size using Racket's composable control

Galler — 2012-05-24T17:31:21

Y, that's closer to what I had in mind.


On Thu, May 24, 2012 at 1:18 PM, Eli Barzilay wrote:

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Re: Finite State Machines of Arbitrary Size using Racket's composable control

Eli Barzilay — 2012-05-24T17:18:21

IIUC, you could do that with something like this:

  (define (encode v)
    (define (get i) (vector-ref v i))
    (define last (sub1 (vector-length v)))
    (define (next S i) (when (< i last) (S (add1 i))))
    (define (B signal i)
      (if (= 0 signal)
        (begin (printf "~s)" (sub1 i))
               A)
        B))
    (define (A signal i)
      (if (= 0 signal)
        A
        (begin (printf "(~s " i)
               B)))
    (for/fold ([state A]) ([signal (in-vector v)] [i (in-naturals)])
      (state signal i)))

But it seems redundant since the abstraction was practically there in
`next'.

Re: Finite State Machines of Arbitrary Size using Racket's composable control

Galler — 2012-05-24T17:07:05

Eli,

I fully agree with you that any FSM is equivalent to functional 
composition and can be implemented in the manner you show.

However , in the way you've implemented the signal-handlers

  (define (B i)

I believe you have the signal handler B both reading the signal (get i) 
and advancing to the next position in the signal-stream (next A i)

Whereas the method I presented with composable continuations separates

1) reading the signal

2) processing the signal in the signal-handlers

3) moving to the next signal in the signal stream

4) transitioning between states


Let me sit down tonight and figure out if those are possible purely with 
functional composition.

R./
Zack



On Thu, May 24, 2012 at 11:59 AM, Eli Barzilay wrote:


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Re: Finite State Machines of Arbitrary Size using Racket'scomposable control

Stephen Bloch — 2012-05-24T16:28:37

On May 24, 2012, at 11:59 AM, Eli Barzilay wrote:


I included a couple of problems in _Picturing Programs_ (section 22.5 and perhaps 22.7) intended to lead students to this approach to FSM's.  Unfortunately, since I added those problems, I haven't had any students who actually got to those problems (this semester's CS0 class only touched on lists for a week, and last semester's didn't get to lists at all), so I don't know how those problems actually work in the classroom.  Anybody out there who's tried them?

Stephen Bloch
sbloch-0gPNHT79tk6Vc3sceRu5cw< at >public.gmane.org


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Re: Finite State Machines of Arbitrary Size using Racket's composable control

Eli Barzilay — 2012-05-24T15:59:31

Note that the FSM part of your code always passes around a simple tail
continuation, which means that you could just use tail calls to do the
same.  Here's a version of this -- I intentionally left most of it as
in your code, except for banging the counter which isn't really
needed.

  (define/contract (list-of-ranges-of-ones vtr)
    (-> (vectorof (or/c 1 0)) list?)
    (read (open-input-string
           (with-output-to-string
             (λ () (display "(") (encode vtr) (display ")"))))))
  
  (define (encode v)
    (define (get i) (vector-ref v i))
    (define last (sub1 (vector-length v)))
    (define (next S i) (when (< i last) (S (add1 i))))
    (define (B i)
      (if (= 0 (get i))
        (begin (printf "~s)" (sub1 i))
               (next A i))
        (next B i)))
    (define (A i)
      (if (= 0 (get i))
        (next A i)
        (begin (printf "(~s " i)
               (next B i))))
    (A 0))

Re: use of `raco setup -l ...`

Danny Heap — 2012-05-24T14:06:08

Thanks Ryan and Neil, this works (with the .plt extension).
  
On Wed, May 23, 2012 at 05:50:57PM -0400, Neil Van Dyke wrote:

Re: use of `raco setup -l ...`

Neil Van Dyke — 2012-05-23T21:50:57

You might also need the ".plt" (for historical reasons):

raco setup -P dsheap vis-eval.plt 1 0

Neil V.

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Re: use of `raco setup -l ...`

Ryan Culpepper — 2012-05-23T21:17:24

You need to use "planet -P" instead:

   raco setup -P dsheap vis-eval 1 0

Ryan
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use of `raco setup -l ...`

Danny Heap — 2012-05-23T21:04:54

I want to restrict to setting up just the collection I'm developing.
I've created a development link `raco planet link dsheap vis-eval 1 0
<path-to-package-dir>`, and now I'd like to generate documentation (or
at least see just the errors generated when I do), so I try

    raco setup -l dsheap/vis-eval:1:0

...but this generates an error, as does

   raco setup -l <path-to-package-dir>

Re: module browser

Ryan Culpepper — 2012-05-23T20:17:20

Whoops, that '+' should be a '*'.

Ryan

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Re: module browser

Ryan Culpepper — 2012-05-23T20:04:40

IIRC, 'check-requires' does in fact inspect syntax templates. The 
problem is that it's not possible to predict in what phase(s) the 
identifiers in a syntax template will be interpreted.

For example, consider this module:

(module AMB racket
   (require (for-template (rename-in racket/base [- shifty]))
            (only-in racket/base [+ shifty]))
   (define shifty-stx #'(shifty 1 2))
   (provide shifty-stx))

Does the occurrence of 'shifty' in the syntax template refer to '+' or 
'-'? It might be both.

If it's used in a macro, 'shifty' means '-':

   (require (for-syntax 'AMB))
   (define-syntax m (lambda _ shifty-stx))
   (m)
   ;; => -1

but if it's evaluated with 'eval', 'shifty' means '+':

   (require 'AMB)
   (eval shifty-stx (make-base-namespace))

(Exercise: add (require (for-meta 2 (rename-in racket/base [+ shifty]))) 
to AMB. See if you can construct a program that interprets 'shifty' as '*'.)

--

But I'd estimate that 90% of the time, an identifier in a syntax 
template is interpreted at the phase one less than the phase the syntax 
template occurs in. And 90% of the remaining cases it's interpreted in 
the same phase as the syntax template. So that's what 'check-requires' 
assumes (see 'analyze/quote-syntax' in 
macro-debugger/analysis/private/get-references).

If 'check-requires' isn't seeing dependencies from syntax templates, can 
you send me an example?

 > For another example (or

I don't understand what you mean. Can you give an example?

Ryan



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Re: module browser

Neil Van Dyke — 2012-05-23T19:31:04

Thanks, Ryan, that info is helpful, although it's missing most of the 
reasons I've had to partition one library into several modules (macro 
transformers).

As people have mentioned before, there seems to be a theoretical brick 
wall preventing these tools from seeing references that likely will be 
used in the results of macro transformations.  I don't understand that 
in all cases.  For one example, the transformers often have templates 
that should know many of the symbols and exactly where they're coming 
from.  (Is this information from templates lost too soon?  Is the 
information from templates not as precise as I assumed?)  For another 
example (or possibly the same thing), these tools seem to be missing 
references in the code of "syntax-parse" productions that is outside 
templates and that I'd think is unambiguous.

BTW, a student who is bored over the summer could do worse than to 
enhance the Module Browser in some other ways.  First low-hanging fruit 
step might be to put the information from "check-requires" into tooltips 
on the arrows.  Then there's a lot one could do with graph drawing.  
And, as a small graphics tweak, you can make it skip redundant repaints 
queued up when dragging.  (Summer is good for this.  More than a little 
sun exposure will just age your skin prematurely and give you melanoma, 
anyway.)

Neil V.

Ryan Culpepper wrote at 05/23/2012 02:28 PM:
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Re: module browser

Eli Barzilay — 2012-05-23T19:07:23

IMO "text based" is the wrong term -- instead it should be "general
api".  IOW, the right thing would be to redo the module browser (and
check-syntax, given the above) using your code.  (Likely requires
adding functionality to your tool so it can do everything.)

Re: module browser

Ryan Culpepper — 2012-05-23T19:02:52

FWIW, check-requires was inspired by DrRacket's Check Syntax tool. 
However, because Check Syntax has to map its results back onto the 
original program, it sometimes loses information. For example, sometimes 
it can't connect required modules with the syntax that requires them.

Ryan



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Re: module browser

Matthias Felleisen — 2012-05-23T18:34:36

It is amazing how often this request comes up and we give the same answer again .. a text-based tool. 


On May 23, 2012, at 2:28 PM, Ryan Culpepper wrote:



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Re: module browser

Ryan Culpepper — 2012-05-23T18:28:10

You can get this information (in text form) from the check-requires 
utility. You may find the code in macro-debugger/analysis/check-requires 
(and its dependencies) useful if you want to add this information to the 
module browser. Getting the set of references is actually somewhat 
tricky, and I think my code does as good a job as possible.

Ryan
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module browser

Neil Van Dyke — 2012-05-23T18:13:09

In the Module Browser, has anyone tried annotating the graph edges with 
imported symbols that are actually referenced by the importing module?  
Maybe further annotate those symbols with phases?

Neil V.

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