| Andrew Cooke | Contents | Latest | RSS | Twitter | Previous | Next

C[omp]ute

Welcome to my blog, which was once a mailing list of the same name and is still generated by mail. Please reply via the "comment" links.

Always interested in offers/projects/new ideas. Eclectic experience in fields like: numerical computing; Python web; Java enterprise; functional languages; GPGPU; SQL databases; etc. Based in Santiago, Chile; telecommute worldwide. CV; email.

Personal Projects

Lepl parser for Python.

Colorless Green.

Photography around Santiago.

SVG experiment.

Professional Portfolio

Calibration of seismometers.

Data access via web services.

Cache rewrite.

Extending OpenSSH.

C-ORM: docs, API.

Last 100 entries

Tomato Chutney; Analysis of Support for Trump; Indian SF; TP-Link TL-WR841N DNS TCP Bug; TP-Link TL-WR841N as Wireless Bridge; Sending Email On Time; Maybe run a command; Sterile Neutrinos; Strawberry and Banana Jam; The Best Of All Possible Worlds; Kenzaburo Oe: The Changeling; Peach Jam; Taste Test; Strawberry and Raspberry Jam; flac to mp3 on OpenSuse 42.1; Also, Sebald; Kenzaburo Oe Interview; Otake (Kitani Minoru) move Black 121; Is free speech in British universities under threat?; I am actually good at computers; Was This Mansplaining?; WebFaction / LetsEncrypt / General Disappointment; Sensible Philosophy of Science; George Ellis; Misplaced Intuition and Online Communities; More Reading About Japan; Visibilty / Public Comments / Domestic Violence; Ferias de Santiago; More (Clearly Deliberate); Deleted Obit Post; And then a 50 yo male posts this...; We Have Both Kinds Of Contributors; Free Springer Books; Books on Religion; Books on Linguistics; Palestinan Electronica; Books In Anthropology; Taylor Expansions of Spacetime; Info on Juniper; Efficient Stream Processing; The Moral Character of Crypto; Hearing Aid Info; Small Success With Go!; Re: Quick message - This link is broken; Adding Reverb To The Echo Chamber; Sox Audio Tools; Would This Have Been OK?; Honesty only important economically before institutions develop; Stegangraphy via PS4; OpenCL Mess; More Book Recommendations; Good Explanation of Difference Between Majority + Minority; Musical Chairs - Who's The Privileged White Guy; I can see straight men watching this conversation and laffing; Meta Thread Defending POC Causes POC To Close Account; Indigenous People Of Chile; Curry Recipe; Interesting Link On Marginality; A Nuclear Launch Ordered, 1962; More Book Recs (Better Person); It's Nuanced, And I Tried, So Back Off; Marx; The Negative Of Positive; Jenny Holzer Rocks; Huge Article on Cultural Evolution and More; "Ignoring language theory"; Negative Finger Counting; Week 12; Communication Via Telecomm Bids; Finding Suspects Via Relatives' DNA From Non-Crime Databases; Statistics and Information Theory; Ice OK in USA; On The Other Hand; (Current Understanding Of) Chilean Taxes / Contributions; M John Harrison; Playing Games on a Cloud GPU; China Gamifies Real Life; Can't Help Thinking It's Thoughtcrime; Mefi Quotes; Spray Painting Bike Frame; Weeks 10 + 11; Change: No Longer Possible To Merge Metadata; Books on Old Age; Health Tree Maps; MRA - Men's Rights Activists; Writing Good C++14; Risk Assessment - Fukushima; The Future of Advertising and Surveillance; Travelling With Betaferon; I think I know what I dislike so much about Metafilter; Weeks 8 + 9; More; Pastamore - Bad Italian in Vitacura; History Books; Iraq + The (UK) Governing Elite; Answering Some Hard Questions; Pinochet: The Dictator's Shadow; An Outsider's Guide To Julia Packages; Nobody gives a shit; Lepton Decay Irregularity; An Easier Way

© 2006-2015 Andrew Cooke (site) / post authors (content).

Basic 2D Geometry Routines

From: "andrew cooke" <andrew@...>

Date: Sat, 18 Aug 2007 16:28:41 -0400 (CLT)

I *think* this is fairy efficient, but haven't actually done any profiling
(I know...)

":";exec snow -- "$0" "$@"

(package* napito-base/v1.0.0

  (provide:
   (define (nap-default-transform)))

  (author: "Andrew Cooke <andrew at acooke.org>")
  (homepage: "http://www.acooke.org")
  (description: "Napito drawing description language - support routines")
  (keywords: graphics)
  (license: gpl/v3.0))

(define (nap-default-transform) '(1 0 0 0 1 0))

(define-syntax dot
  (syntax-rules ()
    ((_ (op1 arg1 ...) (op2 arg2 ...))
     (receive (a b c) (op1 arg1 ...)
       (receive (x y z) (op2 arg2 ...)
         (+ (* a x) (* b y) (* c z)))))))

(define-syntax row1 (syntax-rules () ((_ a b c d e f) (values a b c))))
(define-syntax row2 (syntax-rules () ((_ a b c d e f) (values d e f))))
(define-syntax col1 (syntax-rules () ((_ a b c d e f) (values a d 0))))
(define-syntax col2 (syntax-rules () ((_ a b c d e f) (values b e 0))))
(define-syntax col3 (syntax-rules () ((_ a b c d e f) (values c f 1))))
(define-syntax xyz  (syntax-rules () ((_ x y)         (values x y 1))))

(define-syntax split (syntax-rules () ((_ lst) (values (car lst) (cdr
lst)))))

(define (unpack6 lst)
  (receive (a as) (split lst)
    (receive (b bs) (split as)
      (receive (c cs) (split bs)
        (receive (d ds) (split cs)
          (receive (e es) (split ds)
            (receive (f fs) (split es)
              (values a b c d e f))))))))

(define (unpack2 lst)
  (receive (a as) (split lst)
    (receive (b bs) (split as)
      (values a b))))

(define (nap-transform-point transform point)
  (receive (a b c d e f) (unpack6 transform)
    (receive (x y) (unpack2 point)
      (list (dot (row1 a b c d e f) (xyz x y))
            (dot (row2 a b c d e f) (xyz x y))))))

(define (nap-join-transforms before extra)
  (receive (p q r s t u) (unpack6 before)
    (receive (a b c d e f) (unpack6 extra)
      (list (dot (row1 p q r s t u) (col1 a b c d e f))
            (dot (row1 p q r s t u) (col2 a b c d e f))
            (dot (row1 p q r s t u) (col3 a b c d e f))
            (dot (row2 p q r s t u) (col1 a b c d e f))
            (dot (row2 p q r s t u) (col2 a b c d e f))
            (dot (row2 p q r s t u) (col3 a b c d e f))))))

(test*
 (let ((unit '(1 0 0 0 1 0))
       (doublex '(2 0 0 0 1 0))
       (incx '(1 0 1 0 1 0))
       (one '(1 1)))
   (expect* (equal? '(1 1) (nap-transform-point unit one)))
   (expect* (equal? '(2 1) (nap-transform-point doublex one)))
   (expect* (equal? '(2 1) (nap-transform-point incx one)))
   (expect* (equal? unit (nap-join-transforms unit unit)))
   (expect* (equal? '(4 1)
                    (nap-transform-point
                     (nap-join-transforms doublex incx) one)))
   (expect* (equal? '(3 1)
                    (nap-transform-point
                     (nap-join-transforms incx doublex) one)))))

More Specific Operations

From: "andrew cooke" <andrew@...>

Date: Sat, 18 Aug 2007 17:00:31 -0400 (CLT)

(define (nap-shift-x d) (list 1 0 d 0 1 0))
(define (nap-shift-y d) (list 1 0 0 0 1 d))
(define (nap-scale f) (list f 0 0 0 f 0))
(define (nap-scale-x f) (list f 0 0 0 1 0))
(define (nap-scale-y f) (list 1 0 0 0 f 0))
(define pi 3.1415926)
(define (nap-rotate-deg d)
  (let* ((r (/ (* pi d) 180))
         (c (cos r))
         (s (sin r)))
    (list c (- s) 0 s c 0)))

(test*
 (define (almost-equal? ab pq)
   (define (close x y) (< (abs (- x y)) 0.01))
   (receive (a b) (unpack2 ab)
     (receive (p q) (unpack2 pq)
       (and (close a p) (close b q)))))
 (let ((unit '(1 0 0 0 1 0))
       (incx2 (nap-shift-x 2))
       (incy3 (nap-shift-y 3))
       (double (nap-scale 2))
       (scalex3 (nap-scale-x 3))
       (scaley4 (nap-scale-y 4))
       (rot90 (nap-rotate-deg 90))
       (one '(1 1)))
   (expect* (equal? '(3 1) (nap-transform-point incx2 one)))
   (expect* (equal? '(1 4) (nap-transform-point incy3 one)))
   (expect* (equal? '(2 2) (nap-transform-point double one)))
   (expect* (equal? '(3 1) (nap-transform-point scalex3 one)))
   (expect* (equal? '(1 4) (nap-transform-point scaley4 one)))
   (expect* (almost-equal? '(0.999 -0.001) '(1 0)))
   (expect* (almost-equal? '(-1 1) (nap-transform-point rot90 one)))))

Andrew

Not Efficient!

From: "andrew cooke" <andrew@...>

Date: Sun, 19 Aug 2007 18:00:57 -0400 (CLT)

The values/receive code is constructing and discarding vectors,
apparently.  need to rewrite...

Andrew

Significantly Faster

From: "andrew cooke" <andrew@...>

Date: Sun, 19 Aug 2007 21:15:33 -0400 (CLT)

I've removed values/receive by (1) using CPS in the macros that select
particular elements and (2) using vectors, which simplifies unpacking.

":";exec snow -- "$0" "$@"

; this is about 40% faster than napito-base.scm

; qp6 napito: ./napito-vector.scm
; warming up
; 100000 timing
; (time (speed 1 %%n1414))
;     1403 ms real time
;     1316 ms cpu time (1316 user, 0 system)
;     95 collections accounting for 571 ms real time (548 user, 0 system)
;     891208784 bytes allocated
;     no minor faults
;     no major faults

(package* napito-vector/v1.0.0

  (provide:
   (define nap-default-transform)
   (define (nap-transform-handler engine))
   (define (nap-join-transforms before extra))
   (define (nap-transform-point transform point)))

  (author: "Andrew Cooke <andrew at acooke.org>")
  (homepage: "http://www.acooke.org")
  (description: "Napito drawing description language - support routines")
  (keywords: graphics)
  (license: gpl/v3.0))

(define nap-default-transform '#(1 0 0 0 1 0))

(define (dot a b c) (lambda (p q r) (+ (* a p) (* b q) (* c r))))

(define-syntax row1 (syntax-rules () ((_ a b c d e f fun) (fun a b c))))
(define-syntax row2 (syntax-rules () ((_ a b c d e f fun) (fun d e f))))
(define-syntax col1 (syntax-rules () ((_ a b c d e f fun) (fun a d 0))))
(define-syntax col2 (syntax-rules () ((_ a b c d e f fun) (fun b e 0))))
(define-syntax col3 (syntax-rules () ((_ a b c d e f fun) (fun c f 1))))
(define-syntax xyz  (syntax-rules () ((_ x y fun)         (fun x y 1))))

; this is *much* slower
; (define (row1 a b c d e f fun) (fun a b c))
; (define (row2 a b c d e f fun) (fun d e f))
; (define (col1 a b c d e f fun) (fun a d 0))
; (define (col2 a b c d e f fun) (fun b e 0))
; (define (col3 a b c d e f fun) (fun c f 1))
; (define (xyz  x y fun)         (fun x y 1))

(define (unpack6 vec fun)
  (let* ((a (vector-ref vec 0))
         (b (vector-ref vec 1))
         (c (vector-ref vec 2))
         (d (vector-ref vec 3))
         (e (vector-ref vec 4))
         (f (vector-ref vec 5)))
    (fun a b c d e f)))

(define (unpack2 vec fun)
  (let* ((a (vector-ref vec 0))
         (b (vector-ref vec 1)))
    (fun a b)))

(define (nap-transform-point transform point)
  (unpack6 transform (lambda (a b c d e f)
    (unpack2 point (lambda (x y)
      (vector (row1 a b c d e f (xyz x y dot))
              (row2 a b c d e f (xyz x y dot))))))))

(define (nap-join-transforms before extra)
  (unpack6 before (lambda (p q r s t u)
    (unpack6 extra (lambda (a b c d e f)
      (vector (row1 p q r s t u (col1 a b c d e f dot))
              (row1 p q r s t u (col2 a b c d e f dot))
              (row1 p q r s t u (col3 a b c d e f dot))
              (row2 p q r s t u (col1 a b c d e f dot))
              (row2 p q r s t u (col2 a b c d e f dot))
              (row2 p q r s t u (col3 a b c d e f dot))))))))

(test*
 (let ((unit '#(1 0 0 0 1 0))
       (doublex '#(2 0 0 0 1 0))
       (incx '#(1 0 1 0 1 0))
       (one '#(1 1)))
   (expect* (equal? '#(1 1) (nap-transform-point unit one)))
   (expect* (equal? '#(2 1) (nap-transform-point doublex one)))
   (expect* (equal? '#(2 1) (nap-transform-point incx one)))
   (expect* (equal? unit (nap-join-transforms unit unit)))
   (expect* (equal? '#(4 1)
                    (nap-transform-point
                     (nap-join-transforms doublex incx) one)))
   (expect* (equal? '#(3 1)
                    (nap-transform-point
                     (nap-join-transforms incx doublex) one)))))

(define (nap-shift-x d) (list 1 0 d 0 1 0))
(define (nap-shift-y d) (list 1 0 0 0 1 d))
(define (nap-scale f) (list f 0 0 0 f 0))
(define (nap-scale-x f) (list f 0 0 0 1 0))
(define (nap-scale-y f) (list 1 0 0 0 f 0))
(define pi 3.1415926)
(define (nap-rotate-deg d)
  (let* ((r (/ (* pi d) 180))
         (c (cos r))
         (s (sin r)))
    (list c (- s) 0 s c 0)))

(test*
 (define (almost-equal? ab pq)
   (define (close x y) (< (abs (- x y)) 0.01))
   (receive (a b) (unpack2 ab)
     (receive (p q) (unpack2 pq)
       (and (close a p) (close b q)))))
 (let ((unit '#(1 0 0 0 1 0))
       (incx2 (nap-shift-x 2))
       (incy3 (nap-shift-y 3))
       (double (nap-scale 2))
       (scalex3 (nap-scale-x 3))
       (scaley4 (nap-scale-y 4))
       (rot90 (nap-rotate-deg 90))
       (one '#(1 1)))
   (expect* (equal? '#(3 1) (nap-transform-point incx2 one)))
   (expect* (equal? '#(1 4) (nap-transform-point incy3 one)))
   (expect* (equal? '#(2 2) (nap-transform-point double one)))
   (expect* (equal? '#(3 1) (nap-transform-point scalex3 one)))
   (expect* (equal? '#(1 4) (nap-transform-point scaley4 one)))
   (expect* (almost-equal? '#(0.999 -0.001) '#(1 0)))
   (expect* (almost-equal? '#(-1 1) (nap-transform-point rot90 one)))
   (expect* (equal? '#(3 4) (nap-transform-point
                            (nap-join-transforms incx2 incy3) one)))))

; this wraps an engine and normalizes all transform actions
(define (nap-transform-handler engine)
  (define (forward transform)
    (engine 'nap-transform transform))
  (lambda (action args)
    (case action
      ((nap-shift-x) (forward (nap-shift-x (car args))))
      ((nap-shift-y) (forward (nap-shift-y (car args))))
      ((nap-scale) (forward (nap-scale (car args))))
      ((nap-scale-x) (forward (nap-scale-x (car args))))
      ((nap-scale-y) (forward (nap-scale-y (car args))))
      ((nap-rotate-deg) (forward (nap-rotate-deg (car args))))
      (else (engine action args)))))

(define (speed n limit)
  (if (> n limit)
      '()
      (let ((a (vector n n n n n n))
            (b (vector n n n n n n)))
        (nap-join-transforms a b)
        (speed (+ n 1) limit))))

(define (measure n)
  (display "warming up\n")
  (speed 1 n)
  (display (list n " timing\n"))
  (time (speed 1 n)))

(measure 100000)

Andrew

Comment on this post