Archivo:Animated construction of Sierpinski Triangle.gif

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Resumen

 
Este diagrama fue creado con SageMath.
Descripción
English: Animated construction of Sierpinski Triangle

Self-made.

Licencia

I made this with SAGE, an open-source math package. The latest source code lives here, and has a few better variable names & at least one small bug fix than the below. Others have requested source code for images I generated, below. Code is en:GPL; the exact code used to generate this image follows:

#*****************************************************************************
#       Copyright (C) 2008 Dean Moore  < dean dot moore at deanlm dot com >
#                                      < deanlorenmoore@gmail.com >           
#                                        
#
#  Distributed under the terms of the GNU General Public License (GPL)
#                  http://www.gnu.org/licenses/
#*****************************************************************************
#################################################################################
#                                                                               #
# Animated Sierpinski Triangle.                                                 #
#                                                                               #
# Source code written by Dean Moore, March, 2008, open source GPL (above),      #
# source code open to the universe.                                             #
#                                                                               #
# Code animates construction of a Sierpinski Triangle.                          #
#                                                                               #
# See any reference on the Sierpinski Triangle, e.g., Wikipedia at              #
# < http://en.wikipedia.org/wiki/Sierpinski_triangle >; countless others are    #
# out there.                                                                    #
#                                                                               #
#                              Other info:                                      #
#                                                                               #
# Written in sage mathematical package sage (http://www.sagemath.org/), hence   #
# heavily using computer language Python (http://www.python.org/).              #
#                                                                               #
# Important algorithm note:                                                     #
#                                                                               #
# This code does not use recursion.                                             #
#                                                                               #
# More topmatter & documentation probably irrelevant to most:                   #
#                                                                               #
# Inspiration: I viewed it an interesting problem, to try to do an animated     #
# construction of a Sierpinski Triangle in sage.  Thought I'd be lazy & search  #
# the 'Net for open-source versions of this I could simply convert to sage, but #
# the open-source code I found was poorly documented & I couldn't figure it     #
# out, so I gave up & solved the problem from scratch.                          #
#                                                                               #
# Also, I wanted to animate the construction, which I did not find in           #
# open-source code on the 'Net.                                                 #
#                                                                               #
# Comments on algorithm:                                                        #
#                                                                               #
# The code I found on the 'Net was recursive.  I do not much like recursion,    #
# considering it way for programmers to say, "Look how smart I am!  I'm using   #
# recursion!  Aren't I cool?!"  I feel strongly recursion is often confusing,   #
# can chew up too much memory, and should be avoided except when                #
#                                                                               #
# a) It's unavoidable, or                                                       #
# b) The code would be atrocious without it.                                    #
#                                                                               #
# Did some thinking & swearing, but concocted a non-recursive method, and by    #
# doing the problem from scratch.  Guess it avoids all charges of copyright     #
# violation, plagiarism, whatever.                                              #
#                                                                               #
# More on algorithm via ASCII art.  Below we have a given triangle, shaded via  #
# x's.                                                                          #
#                                                                               #
# The next "generation" is the blank triangles.  Sit down & start a Sierpinski  #
# Triangle on scratch: the next generation is always two on each side of a      #
# given triangle from the last generation, one on top.  Algorithm takes the     #
# given, shaded triangle (below), and makes the three of the next generation    #
# arising from it.                                                              #
#                                                                               #
# See code for more on how this works.                                          #
#                            __________                                         #
#                            \        /                                         #
#                             \      /                                          #
#                              \    /                                           #
#                               \  /                                            #
#                       _________\/_________                                    #
#                       \ xxxxxxxxxxxxxxxx /                                    #
#                        \ xxxxxxxxxxxxxx /                                     #
#                         \ xxxxxxxxxxxx /                                      #
#                          \ xxxxxxxxxx /                                       #
#                  _________\ xxxxxxxx /_________                               #
#                  \        /\ xxxxxx /\        /                               #
#                   \      /  \ xxxx /  \      /                                #
#                    \    /    \ xx /    \    /                                 #
#                     \  /      \  /      \  /                                  #
#                      \/        \/        \/                                   #
#                                                                               #
#################################################################################
#                                                                               #
# Begin program:                                                                #
#                                                                               #
# First we need three functions; see the below code on how they are used.       #
#                                                                               #
# The three functions *right_side_triangle* , *left_side_triangle* &            #
# *top_triangle* are here defined & not as "lambda" functions, as they need     #
# documented.                                                                   #
#                                                                               #
# I don't care to replicate the poorly-documented code I found on the 'Net.     #
#                                                                               #
#################################################################################
#                                                                               #
# First function, *right_side_triangle*.                                        #
#                                                                               #
# Function *right_side_triangle* gives coordinates of next triangle on right    #
# side of a given triangle whose coordinates are passed in.                     #
#                                                                               #
# Points *p*, *r*, *q*, *s* & *t* are labeled as passed in:                     #
#                                                                               #
#  (p, r)____________________(q, r)                                             #
#        \                  /                                                   #
#         \                /                                                    #
#          \              /                                                     #
#           \            /                                                      #
#            \  (p1, r1)/_________ (q1, r1)                                     #
#             \        /\        /                                              #
#              \      /  \      /                                               #
#               \    /    \    /                                                #
#                \  /      \  /                                                 #
#                 \/        \/                                                  #
#               (s, t)   (s1, t1)                                               #
#                                                                               #
# p1 = (q + s)/2, a simple average.                                             #
# q1 = q + (q - s)/2 = (3*q - s)/2                                              #
# r1 = (r + t)/2, a simple average.                                             #
# s1 = q, easy.                                                                 #
# t1 = t, easy.                                                                 #
#                                                                               #
#################################################################################   

def right_side_triangle(p,q,r,s,t):

    p1 = (q + s)/2
    q1 = (3*q - s)/2
    r1 = (r + t)/2
    s1 = q        # A placeholder, solely to make code clear.
    t1 = t        # Ditto, a placeholder.  

    return ((p1,r1),(q1, r1),(s1, t1))

# End of function *right_side_triangle*.

#################################################################################
#                                                                               #
# Function *left_side_triangle*:                                                #
#                                                                               #
#                (p, q) ____________________(q, r)                              #
#                       \                  /                                    #
#                        \                /                                     #
#                         \              /                                      #
#                          \            /                                       #
#         (p1, r1) _________\ (q1, r1) /                                        #
#                  \        /\        /                                         #
#                   \      /  \      /                                          #
#                    \    /    \    /                                           #
#                     \  /      \  /                                            #
#                      \/        \/                                             #
#                   (s1, t1)   (s, t)                                           #
#                                                                               #
# p1 = p - (s - p)/2 = (2p-s+p)/2 = (3p - s)/2                                  #
# q1 = (p + s)/2, a simple average                                              #
# r1 = (r + t)/2, a simple average.                                             #
# s1 = p, easy.                                                                 #
# t1 = t, easy.                                                                 #
#                                                                               #
################################################################################# 

def left_side_triangle(p,q,r,s,t): 
 
    p1 = (3*p - s)/2
    q1 = (p + s)/2
    r1 = (r + t)/2
    s1 = p        # A placeholder, solely to make code clear.
    t1 = t        # Ditto, a placeholder.
    
    return ((p1,r1),(q1, r1),(s1, t1))

# End of function *left_side_triangle*.  

#################################################################################
#                                                                               #
# Function *top_triangle*.                                                      #
#                                                                               #
#                   (p1, r1) __________ (q1, r1)                                #
#                            \        /                                         #
#                             \      /                                          #
#                              \    /                                           #
#                               \  / (s1, t1)                                   #
#                 (p, r)_________\/_________                                    #
#                       \ xxxxxxxxxxxxxxxx /                                    #
#                        \ xxxxxxxxxxxxxx / (q, r)                              #
#                         \ xxxxxxxxxxxx /                                      #
#                          \ xxxxxxxxxx /                                       #
#                           \ xxxxxxxx /                                        #
#                            \ xxxxxx /                                         #
#                             \ xxxx /                                          #
#                              \ xx /                                           #
#                               \  /                                            #
#                                \/                                             #
#                              (s, t)                                           #
#                                                                               #
# p1 = (p + s)/2, a simple average.                                             #
# q1 = (s + q)/2, a simple average                                              #
# r1 = r + (r - t)/2 = (3r - t)/2                                               #
# s1 = s, easy.                                                                 #
# t1 = r, easy.                                                                 #
#                                                                               #
#################################################################################

def top_triangle(p,q,r,s,t): 

    p1 = (p + s)/2
    q1 = (s + q)/2
    r1 = (3*r - t)/2
    s1 = s          # Again, both this & next are
    t1 = r          # placeholders, solely to make code clear.

    return ((p1,r1),(q1, r1),(s1, t1))

# End of function *top_triangle*. 

#################################################################################
#                                                                               #
# Main program commences:                                                       #
#                                                                               #
################################################################################# 

# Top matter a user may wish to vary:

number_of_generations   = 8       # How "deep" goes the animation after initial triangle.
first_triangle_color    = (1,0,0) # First triangle's rgb color as red-green-blue tuple.
chopped_piece_color     = (0,0,0) # Color of "chopped" pieces as rgb tuple.
delay_between_frames    = 50      # Time between "frames" of final "movie."
figure_size             = 12      # Regulates size of final image.
initial_edge_length     = 3^7     # Initial edge length. 

# End of material user may realistically vary.  Rest should churn without user input.

number_of_triangles_in_last_generation = 3^number_of_generations # Always a power of three.
images                                 = []                      # Holds images of final "movie."  
coordinates                            = []                      # Holds coordinates. 

p0 = (0,0)                                # Initial points to start iteration -- note
p1 = (initial_edge_length, 0)             # y-values of *p0* & *p1* are the same -- an
p2 = ((p0[0] + p1[0])/2,                  # important book-keeping device.
     ((initial_edge_length/2)*sin(pi/3))) # Equilateral triangle; see any Internet
                                          # reference on these.

# We make a polygon (triangle) of initial points:

this_generations_image = polygon((p0, p1, p2), rgbcolor=first_triangle_color) 

images.append(this_generations_image) # Save image from last line.

coordinates = [( ( (p0[0] + p2[0])/2, (p0[1] + p2[1])/2 ),   # Coordinates
                 ( (p1[0] + p2[0])/2, (p1[1] + p2[1])/2 ),   # of second
                 ( (p0[0] + p1[0])/2, (p0[1] + p1[1])/2 ) )] # triangle.
                                                             # It is *supremely* important
                                                             # that the y-values of the first two
                                                             # points are equal -- check definitions
                                                             # above & code below.

this_generations_image = polygon(coordinates[0],             # Image of second triangle.
                                 rgbcolor=chopped_piece_color)
images.append(images[0] + this_generations_image) # Save second image, tacked on top of first.

# Now the loop that makes the images: 

number_of_triangles_in_this_generation = 1 # We have made one "chopped" triangle, the second, above.

while number_of_triangles_in_this_generation < number_of_triangles_in_last_generation:

    this_generations_image       = Graphics() # Holds next generation's image, initialize.
    next_generations_coordinates = []         # Holds next generation's coordinates, set to null. 

    for a,b,c in coordinates: # Loop on all triangles.

        (p, r)  = a      # Right point; note y-value of this & next are equal.
        (q, r1) = b      # Left point; note r1 = r & thus *r1* is irrelevant;
                         # it's only there for book-keeping.
        (s, t)  = c      # Bottom point.

        # Now construct the three triangles & their three polygons of the next
        # generation.

        right_triangle = right_side_triangle(p,q,r,s,t) # Here use those
        left_triangle  = left_side_triangle (p,q,r,s,t) # utility functions
        upper_triangle = top_triangle       (p,q,r,s,t) # defined at top.

        right = polygon(right_triangle, rgbcolor=(chopped_piece_color)) # Make next
        left  = polygon(left_triangle,  rgbcolor=(chopped_piece_color)) # generation's
        top   = polygon(upper_triangle, rgbcolor=(chopped_piece_color)) # triangles.

        this_generations_image = this_generations_image + (right + left + top) # Add image.
        
        next_generations_coordinates.append(right_triangle) # Save the coordinates
        next_generations_coordinates.append( left_triangle) # of triangles of the
        next_generations_coordinates.append(upper_triangle) # next generation.

       # End of "for a,b,c" loop.

    coordinates = next_generations_coordinates         # Save for next generation.
    images.append(images[-1] + this_generations_image) # Make next image: all previous
                                                       # images plus latest on top.
    number_of_triangles_in_this_generation *= 3        # Bump up.
 
# End of *while* loop.

a = animate(images, figsize=[figure_size, figure_size], axes=False) # Make image, ...
a.show(delay = delay_between_frames)                                # Show image.
 
 # End of program.

End of code.
Fecha

23 de marzo de 2008 (fecha original de carga)

(Texto original: «March 23, 2008»)
Fuente Trabajo propio (Texto original: «self-made»)
Autor

Dino de Wikipedia en inglés

(Texto original: «dino (talk)»)

Licencia

Dino de Wikipedia en inglés, titular de los derechos de autor de esta obra, la publica en los términos de las siguientes licencias:
w:es:Creative Commons
atribución compartir igual
Este archivo se encuentra bajo la licencia Creative Commons Genérica de Atribución/Compartir-Igual 3.0.
Atribución: Dino de Wikipedia en inglés
Eres libre:
  • de compartir – de copiar, distribuir y transmitir el trabajo
  • de remezclar – de adaptar el trabajo
Bajo las siguientes condiciones:
  • atribución – Debes otorgar el crédito correspondiente, proporcionar un enlace a la licencia e indicar si realizaste algún cambio. Puedes hacerlo de cualquier manera razonable pero no de manera que sugiera que el licenciante te respalda a ti o al uso que hagas del trabajo.
  • compartir igual – En caso de mezclar, transformar o modificar este trabajo, deberás distribuir el trabajo resultante bajo la misma licencia o una compatible como el original.
GNU head Se autoriza la copia, distribución y modificación de este documento bajo los términos de la licencia de documentación libre GNU, versión 1.2 o cualquier otra que posteriormente publique la Fundación para el Software Libre; sin secciones invariables, textos de portada, ni textos de contraportada. Se incluye una copia de la dicha licencia en la sección titulada Licencia de Documentación Libre GNU.
Puedes usar la licencia que prefieras.

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Aquí se muestra la página de descripción original. Los siguientes nombres de usuario se refieren a en.wikipedia.
  • 2008-03-23 18:33 Dino 1200×1200×7 (344780 bytes) {{Information |Description=Animated construction of Sierpinski Triangle |Source=self-made |Date=March 23, 2008 |Location=Boulder, Colorado |Author=~~~ |other_versions= }} Self-made. Will post source code later.

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Animation construction the Sierpinski Triangle.

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actual02:41 10 feb 2011Miniatura de la versión del 02:41 10 feb 2011950 × 980 (375 kB)DeanmooreSeemingly better version
20:34 12 abr 2008Miniatura de la versión del 20:34 12 abr 20081200 × 1200 (337 kB)יוסי{{Information |Description={{en|Animated construction of Sierpinski Triangle<br/> Self-made. == Licensing: == I made this with SAGE, an open-source math package. The latest source code lives [h

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