Dfenestrator

Day 1

2010-11-01T21:05:00.001-07:00

By the numbers

2010-10-05T00:03:00.000-07:00

That's the last straw. Sage can't handle fractional exponents on negative numbers? Pfaw! No big, can just do it in Mathematica. Functional is more my style, anyway. Dynamically-typed imperative languages are for the lazy or spastic.

So I bequeath to you the Python code of my aborted Sage notebook for my numerical differential equation solver. Euler's method only. Was going to do Improved Euler's and RKx but I'll save it for Mathematica.

Use it together.

Use it in peace.

Cell 1

def Euler(f, x0, y0, xf, h):
    
    x  = float(x0)
    y  = float(y0)
    xf = float(xf)
    h  = float(h)
    
    n = int((xf - x)/h)
        
    xs = [x]
    ys = [y]
    
    for i in range(0, n):
        y = y + h * f(x,y).subs(x=x, y=y).n()
        x = x + h
        xs.append(x)
        ys.append(y)
        
    return [xs,ys]

Cell 2

def TabList(y, headers = None):
    '''
    Converts a list into an html table with borders.
    '''
    s = '<table border = 1>'
    if headers:
        for q in headers:
            s = s + '<th>' + str(q) + '</th>'
    for x in y:
        s = s + '<tr>'
        for q in x:
            s = s + '<td>' + str(q) + '</td>'
        s = s + '</tr>'
    s = s + '</table>'
    return s

Cell 3

class NumericalSolution:
    def __init__(self, fp, x0, y0, xf, h, color = (0,0,1)):
        self.fp = fp
        self.x0 = x0
        self.y0 = y0
        self.xf = xf
        self.h = h
        self.color = color
    def Solve(self):
        raise MethodNotImplemented()
    def ToLine(self):
        X = 0; Y = 1;
        result = self.Solve()
        return line( [[result[X][i], result[Y][i]] for i in range(len(result[X]))], rgbcolor=self.color )

class MethodNotImplemented: pass

Cell 4

class EulerNumericalSolution(NumericalSolution):
    def __init__(self, fp, x0, y0, xf, h, color = (0,0,1)):
        NumericalSolution.__init__(self, fp, x0, y0, xf, h, color)
    def Solve(self):
        #return Euler( self.fp, self.x0, self.y0, self.xf, self.h)
        return Euler( (lambda x,y: self.fp), self.x0, self.y0, self.xf, self.h)

Cell 5

SolverTypes = ["Euler"] #, "Improved Euler", "RK2"]

def GenerateNumericalSolution( fp, solver, color = (0,0,1) ):        
    if solver == "Euler": 
        return EulerNumericalSolution(fp, x0, y0, xf, h, color)
    else:
        raise InvalidSolver()
        
class InvalidSolver: pass

Cell 6

def GetNumericalSolutionLines():
    lines = solutions[0].ToLine()
    for i in range(1, len(solutions)):
        lines += solutions[i].ToLine()
    return lines

Cell 7

f = 0
fColor = (1,0,0)
@interact
def DefineExactFunction( f_in = input_box(-cos(x)+1.0, label = 'f(x) = '),
                         color = color_selector((1,0,0), label='', widget='farbtastic', hide_box=False) ):        
    global f
    global fColor
    f = f_in
    fColor = color
    return

Cell 8

x0 = 0.0
y0 = 0.0
xf = 10.0
h  = 0.1

@interact
def _( _x0 = input_box( x0, label = 'x<sub>0</sub> '),
       _y0 = input_box( y0, label = 'y<sub>0</sub> '),
       _xf = input_box( xf, label = 'x<sub>f</sub> '),
       _h  = input_box(  h, label = 'h ') ):
    global x0; global y0; global xf; global h    
    x0  = _x0; y0  = _y0; xf  = _xf; h = _h;
    
    return

Cell 9

#x0 = 0.0
#y0 = 0.0
#xf = 10.0
#h  = 0.1
#
#@interact
#def _( _x0 = input_box( x0, label = 'x<sub>0</sub> '),
#       _y0 = input_box( y0, label = 'y<sub>0</sub> '),
#       _xf = input_box( xf, label = 'x<sub>f</sub> '),
#       _n  = input_box( int(xf-x0/h), label = 'number of steps ') ):
#    global x0; global y0; global xf; global h    
#    x0  = _x0; y0  = _y0; xf  = _xf; h = (_xf - _x0) / _n;
#    
#    return

Cell 10

# *** Enter Numerical Solutions ***
solutions = []
var('x,y')
@interact
def _(
       fp     = input_box(sin(x), label = "f'(x,y)="),
       solver = selector(SolverTypes, label="Solver="),
       color  = color_selector((0,0,1), label='', widget='farbtastic', hide_box=False),
       action = selector(["Edit","Add","Clear All"], label='', buttons=True)
     ):
    global solutions
    if action == "Add":
        solutions.append( GenerateNumericalSolution( fp, solver, color ) )
    elif action == "Clear All":
        solutions = []
    else:
        pass

    for i in range(len(solutions)):
        html('<font color=\"%s\">$f\'\;(x)\;=\;%s,\;h=%f$</font>' % (solutions[i].color.html_color(), latex(solutions[i].fp), solutions[i].h))
        
    return

Cell 11

@interact
def _( showExact = checkbox (True, "Show exact") ):
    X = 0
    Y = 1
    #try:
    if showExact:
        show( plot(f,x0,xf,rgbcolor=fColor) + GetNumericalSolutionLines() )
    else:
        show( GetNumericalSolutionLines() ) 
    if showExact:
        html('<font color=\"%s\"><center>$f\'\;(x)\;=\;%s\;%s$</center></font>' % ( fColor.html_color(), latex(f), "(exact)" ))    
    for i in range(len(solutions)):
        solution = solutions[i].Solve()
        tableRange = range(len(solution[X]))
        html('<font color=\"%s\"><center>$f\'\;(x)\;=\;%s,\;h=%f$</center></font>' % (solutions[i].color.html_color(), latex(solutions[i].fp), solutions[i].h))    
    #except:
    #print "< < No Functions Configured > >"

Cell 12

@interact
def _( showExact = checkbox (True, "Show exact") ):
    if len(solutions) == 0:
        print "< < No Functions Configured > >"
    else:
        X = 0
        Y = 1
        for i in range(len(solutions)):
            solution = solutions[i].Solve()
            tableRange = range(len(solution[X]))
            html('<font color=\"%s\">$f\'\;(x)\;=\;%s,\;h=%f$</font>' % (solutions[i].color.html_color(), latex(solutions[i].fp), solutions[i].h))
            html('')
            if showExact:
                html(TabList([[j, solution[X][j], solution[Y][j], f(x=solution[X][j]).n()] for j in tableRange], headers = ['step','x','y', 'y (exact)']))
            else:
                html(TabList([[j, solution[X][j], solution[Y][j]] for j in tableRange], headers = ['step','x','y']))
            html('')

Cell 13

@interact
def _( showExact = checkbox (True, "Show exact"),
       displayInterval = input_box( 0.1, label = 'Interval ') ):
    if len(solutions) == 0:
        print "< < No Functions Configured > >"
    else:
        X = 0
        Y = 1

        headers = ['x']
        for i in range(len(solutions)):
            yHeader = "y (h=%f)" % solutions[i].h
            headers.append(yHeader)
        if showExact:
            headers.append('y (exact)')
        
        solution = []
        decimatedSolution = []
        for i in range(len(solutions)):
            solution.append(solutions[i].Solve())
            decimatedSolution.append([])
        #if showExact:
            #solution.append([])
        
        numIntervals = int((xf - x0)/displayInterval)
        
        for i in range(len(solution)):  
            numPointsInInterval = len(solution[i][Y])/numIntervals
            for j in range(numIntervals+1):
                decimatedSolution[i].append(solution[i][Y][int(j*numPointsInInterval)])
        
        vals = []
        for i in range(len(decimatedSolution[0])): # range(len(solution[0][X])-1):
            slice = []
            slice.append(i*displayInterval)
            for j in range(len(solution)):
                slice.append(decimatedSolution[j][i])
            if showExact:
                slice.append(f(x=i*displayInterval).n())
            vals.append(slice)
        html(TabList(vals, headers))

2010-09-14T20:27:00.000-07:00

2010-08-12T00:14:00.000-07:00

2010-06-05T17:55:00.001-07:00

2010-05-24T21:37:00.000-07:00

2010-02-15T14:54:00.000-08:00

"A woman civil engineer wrote from Leningrad: 'I saw your film, Mirror. I sat through to the end, despite the fact that after the first half hour I developed a severe headache as a result of my genuine efforts to analyze it, or just to have some idea of what was going on, of some connection between the characters and events and memories.... We poor cinema-goers see films that are good, bad, very bad, ordinary or highly original. But any of these one can understand, and be delighted or bored as the case may be; but this one?!...' An equipment engineer from Kalinin was also terribly indignant: 'Half an hour ago I came out of Mirror. Well!!... Comrade director! Have you seen it? I think there's something unhealthy about it... I wish you every success in your work, but we don't need films like that.' And another engineer, this time from Sverdlovsk, was unable to contain his deep antipathy: 'How vulgar, what trash! Ugh, how revolting! Anyhow, I think your film's a blank shot. It certainly didn't reach the audience, which is all that matters...' This man even feels that the cinema administration should be called to account: 'One can only be astonished that those responsible for the distribution of films here in the USSR should allow such blunders.' In fairness to the cinema administration, I have to say that 'such blunders' were permitted very seldom — on average once every five years; and when I received letters like that I used to be thrown into despair: yes, indeed, who was I working for, and why?"

Andrei Tarkovsky,
Sculpting in Time

2010-02-15T14:10:00.000-08:00

2009-12-30T15:03:00.001-08:00

2009-12-29T19:17:00.000-08:00

2009-12-25T11:15:00.000-08:00

3 hours

2009-12-20T20:47:00.000-08:00

And what would you have me say, exactly?

1946-2009

2009-12-17T23:34:00.000-08:00

Gone but never forgotten, Dan O'Bannon. What would my childhood have been without that decade of savage Alien nightmares?

Conjunction Junction, what's your function?

2009-12-14T00:13:00.000-08:00

Attention λ-freaks: Brian Beckman on the state monad on Channel 9. Good stuff!

2009-12-13T21:31:00.000-08:00

2009-11-28T18:29:00.000-08:00

2009-11-07T11:14:00.000-08:00

Tuva || bust

2009-10-18T09:31:00.000-07:00

First I've heard of the Tuva project. Good for some Feynman lecture video, at least.

High-functioning functional

2009-10-18T09:18:00.000-07:00

Microsoft's Dr. Erik Meijer washes your imperative programming sins away with a weekly Channel 9 lecture series on Haskell. Throw your pain in the river.

2009-09-14T00:44:00.001-07:00

Oh yeah I used to post this crap

2009-09-13T14:08:00.000-07:00

You say you want a revolution

2009-08-25T19:35:00.000-07:00

Here comes the all-robot proletariat! Paging Herr Marx!

2009-08-22T21:15:00.000-07:00

Adieu Eiffel

2009-08-21T22:25:00.000-07:00

If you're as much as a stickler for mathematically provable code correctness as I am, check out the demo of contracts for C# on Channel 9. Of course they neglect to mention that the static invariant checking option will only be available with the ridiculously pricey team dev license...

Love + Sorrow + World + Dream = ?

2009-08-20T00:24:00.000-07:00

It's a night of blue eyes and Lindenbaum with Mahler's orphaned Blumine and Songs of the Wayfayer + Dvorák's #9 at the Bowl Thursday.

Heaven sent

2009-08-13T00:26:00.000-07:00

J.D. closes his week-long New Bev curatorship with a John Barry double feature tomorrow night only. Plus Xanadu at the Cinematheque on Friday.

Out: Snark / In: Boojum

2009-08-04T20:12:00.000-07:00

Frontispiece to Symbolic Logic, Part 1 by Lewis Carroll

2009-07-19T20:37:00.000-07:00

2009-07-11T16:24:00.000-07:00

2009-07-08T23:59:00.000-07:00

2009-07-01T00:09:00.001-07:00

2009-07-01T00:06:00.001-07:00

2009-06-23T01:39:00.000-07:00

2009-06-21T14:16:00.000-07:00

2009-06-14T09:52:00.000-07:00

Time served

2009-06-04T20:53:00.000-07:00

At last I can lay my dead Schrödinger Kitty to rest. Chris Marker's Le fond de l'air est rouge finally comes to DVD.

More Hobbies of the 21st Century

2009-06-03T23:06:00.000-07:00

The UFO Flyby.

Hobbies of the 21st Century

2009-06-03T22:06:00.000-07:00

First it was videogame stunt videos. Now...

An old high school friend of mine recently mentioned the Fail Blog and I just have to say...

2009-06-02T23:01:00.001-07:00

Truth 23.976 times a second

2009-05-30T22:28:00.000-07:00

He makes more than just quality scissor lifts.

End of the Road: Day 838

2009-05-19T21:58:00.000-07:00

That's right, the long trip is over and I have been safely reintegrated into the Matrix where I can now savor my juicy and delicious steak. Though there's much to be said about the last crazy-ass 2.3 years I need to get back to Chez Hrissikopoulos to slot-a-into-tab-b some Ikea floor lamps and prepare to host my first home invasion. Sweet dreams.

2009-05-19T21:54:00.000-07:00

2009-05-18T19:48:00.000-07:00

2009-05-17T19:28:00.001-07:00

2009-05-16T07:31:00.001-07:00

Hammer Time

2009-05-08T17:35:00.000-07:00

...Within my writings my Zarathustra stands by itself. I have with this book given mankind the greatest gift that has ever been given it. With a voice that speaks across millennia, it is not only the most exalted book that exists, the actual book of the air of the heights -- the entire fact man lies at a tremendous distance beneath it -- it is also the profoundest, born out of the innermost abundance of truth, an inexhaustible well into which no bucket descends without coming up filled with gold and goodness. Here there speaks no 'prophet', none of those gruesome hybrids of sickness and Will to Power called founders of religions... here there speaks no fanatic, here is no 'preaching', here faith is not demanded: out of an infinite abundance of light and depth of happiness there falls drop after drop, word after word -- a tender slowness of pace is the tempo of these discourses. Such things as this reach only the most select; it is an incomparable privilege to be a listener here; no one is free to have ears for Zarathustra... With all this, is Zarathustra not a seducer? ...but what does he himself say when for the first time he again goes back into his solitude? Precisely the opposite of that which any sort of 'sage', 'saint', 'world-redeemer' or other décadent would say in such a case... he does not only speak differently, he is different...

I now go away alone, my disciples! You too now go away and be alone! So I will have it. Go away from me and guard yourselves against Zarathustra! And better still: be ashamed of him! Perhaps he has deceived you. The man of knowledge must be able not only to love his enemies but also to hate his friends. One repays a teacher badly if one remains only a pupil. And why, then, should you not pluck at my laurels? You respect me; but how if one day your respect should tumble? Take care that a falling statue does not strike you dead! You say you believe in Zarathustra? But of what importance is Zarathustra? You are my believers: but of what importance are all believers? You had not yet sought yourselves when you found me. Thus do all believers; therefore all belief is of so little account.

Now I bid you lose me and find yourselves; and only when you have denied me will I return to you...

Friedrich Nietzsche,
Introduction to Ecce Homo

2009-05-07T22:28:00.000-07:00

Day 820

2009-05-01T20:23:00.000-07:00

Wow, just plug in my Wacom Bamboo tablet and turn on speech recognition and suddenly I'm in the future. It really sneaks up on ya. We may not have colonized the moon and dug up that black monolith yet but I did video Skype someone yesterday and then had a nice game of chess by voice with my computer so I guess 2 out of 3 isn't too bad.

Wherefore art thou, Marble Madness?

2009-04-30T22:24:00.000-07:00

Ah, what a sight to behold after all these years -- even if HWG sucks ass. Damn I still love that music.

Psycho commie fascist arthouse

2009-04-21T22:39:00.000-07:00

Coming to Criterion: Masaki Kobayashi's Dead-and-Red sextuple-feature The Human Condition, two or three more by Godard + Roman Polanski's Repulsion, which is pretty much my sex life cinéma vérité.

These are a few of my favorite things

2009-04-18T06:28:00.001-07:00

#37) Curious wireless router names

Ours is not to wonder why

2009-04-09T20:28:00.000-07:00

But for the sheep just another incomprehensible day of fear and trepidation.

2009-03-27T00:32:00.000-07:00

2009-03-24T00:09:00.001-07:00

2009-03-24T00:08:00.000-07:00

2009-03-24T00:07:00.000-07:00

Goodbye Marie Pillet

2009-03-07T18:48:00.000-08:00

What to say?

From the IEEE Computer Society Vault

2009-02-24T20:23:00.000-08:00

Grady and The Real HAL.

Eiffel's Ghost

2009-02-24T19:54:00.000-08:00

Contract-Driven Development options for .NET from Microsoft, et al. Though I hear the MS version only works with the Dev Studio Team licen$e. Still waiting for the knock-off of EiffelStudio's Code/Contract/UMLy-thing view. Maybe I'll finally have a reason to throw Bertrand Meyer's tome back onto the stack.

Don't ask, don't tell

2009-02-20T23:23:00.001-08:00

In the beginning was the keyword

2009-02-05T18:28:00.000-08:00

Unfortunately, this is probably only funny for the superdorks.

Yay! Moving on...

2009-01-20T21:45:00.001-08:00

Peter Bogdanovich in the flesh at the New Beverly on the 21st and 23rd, and programming all next week. No At Long Last Love, alas. I don't care what Brando says, I love Cybill Shepherd's singing.

Alfred Hitchcock Presented

2009-01-06T19:56:00.000-08:00

Lotsa Hitchcock at the Cinematheque starting on the 22nd. What a perfect time to read the book most despised by William Goldman. Or listen to the record ings from whence it was culled.

More fun than NFPA 704

2009-01-06T19:06:00.000-08:00

"Coke or Weed?" is eerily similar to the "Kahlúa, Weed or Cocaine?" game I forced several of my friends to play with Luke Y. Thompson's video of Cathy Seipp's Jahrzeit.

It's Alive!

2009-01-03T18:20:00.001-08:00

Another late night in my hotel room calibrating my 35mm lens adapter and running tests.

So long, 2008

2008-12-31T15:42:00.000-08:00

Seems like it was a tough 12 months for everyone I know -- I feel like I got off easy. Now if you'll excuse me I'm laying low for the rest of the year.

Phase IV

2008-12-13T06:52:00.001-08:00

It begins.

Next up: Wexler

2008-12-11T20:41:00.000-08:00

Get with the program. Haskell Wikibook here. Compiler here. Other resources here. Lambda calculus primer here. People driven mad by λ here.

It's a feature!

2008-12-11T20:19:00.001-08:00

How to blue screen Windows on demand from the people who know.

Renew my subscription to the Resurrection

2008-12-08T20:21:00.000-08:00

Gil Kaplan on Mahler's 2nd on Charlie Rose.

2008-12-07T19:28:00.000-08:00

1924-2008

2008-12-07T18:09:00.000-08:00

Rest in peace, Nina Foch -- at least I got to see you in the flesh. Long may you wave, Leslie Caron.

Day 670

2008-12-01T21:14:00.001-08:00

So as we approach Thoreau's vaunted two years and two months things are -- as expected -- getting a bit hectic. And as the camera department is running wildly over budget due to the DP's insatiable appetite for Canon glass it looks like I'm going to have to break Henry David's record, alas. Unlike our government and key financial institutions, I have to make ends meet. So onward! In other news, the Reliant's onboard computer #1 has had it's XP installation purged and replaced with the preferred OS of anarchists and ecoterrorists, Ubuntu 8.10. Also, the car's drive has been upgraded to 2 terabytes, which I strongly believe is a K-Car storage capacity world record. Now maybe I'll have enough room for my complete collection of guacamole recipes.

2008-11-29T19:13:00.000-08:00

Better, Stronger, Faster

2008-11-25T19:29:00.000-08:00

The new Criterion site is up.

The Paris sky is blue and bright

2008-11-24T22:50:00.000-08:00

Leonard Cohen is on the road again.

All work and no play

2008-11-10T20:44:00.000-08:00

Well, I'm kind of busy at the moment, so feel free to entertain yourselves with some footage of high-tension arcs.

2008-10-29T22:14:00.000-07:00

2008-10-25T13:53:00.000-07:00

Soviet Prop-a-gander

2008-10-25T13:35:00.000-07:00

What's it like being neighbors with MySpace? Don't know; never see the guy. But he does like to rack his shotgun a lot in the wee hours of the morning.

2008-10-21T21:57:00.000-07:00

2008-10-21T21:40:00.000-07:00

2008-10-18T11:30:00.000-07:00

2008-10-12T18:46:00.000-07:00

Wouldn't you cross the street?

2008-10-09T23:46:00.000-07:00

1.6 years on the street and the transformation is complete. 1080p sure looks nice, though.

Seal Beach to Sunset Blvd

2008-10-09T22:46:00.000-07:00

.
1.25 hours for me, 2.5 minutes for you.

2008-10-07T23:12:00.001-07:00

2008-09-28T23:44:00.000-07:00

This one's for you, Kolb

2008-09-28T09:35:00.000-07:00

Dream Brother, with your tears scattered 'round the world

2008-09-28T09:10:00.000-07:00

Hey, Kolb from PA is into Tesla Coils and Nietzsche -- could he be my long-lost half-brother?

Isolde:

2008-09-28T08:58:00.000-07:00

Dein Werk?
O tör'ge Magd!
Frau Minne kenntest du nicht?
Nicht ihrer Wunder Macht?
Des kühnsten Mutes
Königin?
Des Weltenwerdens
Walterin?
Leben und Tod
sind untertan ihr,
die sie webt aus Lust und Leid,
in Liebe wandelnd den Neid.
Des Todes Werk,
nahm ich's vermessen zur Hand,
Frau Minne hat es
meiner Macht entwandt.
Die Todgeweihte
nahm sie in Pfand,
faßte das Werk
in ihre Hand.
Wie sie es wendet,
wie sie es endet,
was sie mir küre,
wohin mich führe,
ihr ward ich zu eigen:
num laß mich Gehorsam zeigen!

The week that was

2008-09-22T20:49:00.000-07:00

Highlights: brief (and not-so-brief) encounters with Werner Herzog, Godfrey Reggio and my first shrapnel wound courtesy of the nimrod in the lane next to me at the range who couldn't hit his target at <10 yards with his rented 12 gage shotgun.

2008-09-21T13:57:00.001-07:00

Prop-a-gander

2008-09-20T13:03:00.000-07:00

The Statuette of Liberty

Boob Tube

2008-09-20T12:50:00.000-07:00

Also shown at last night's Qatsi event. And no, they're not being given a stern talking to by Amy Alkon.

Godfrey Reggio: "The Blue Planet is the new Swastika."

2008-09-20T00:14:00.000-07:00

I was both titillated and disturbed to see that the movie that was so ethereal and mysterious to me when I first saw it back in 1991 is in 2008 a highly recognizable documentation of the commute for my last two jobs. An invitation for meditation indeed.

Prop-a-gander

2008-09-15T19:57:00.000-07:00

Ben's sister's camera

2008-09-14T20:47:00.000-07:00

2008-09-14T00:32:00.000-07:00

2008-09-07T07:18:00.000-07:00