From Wikipedia, the free encyclopedia
Original file (2,010 × 2,010 pixels, file size: 8 KB, MIME type: image/png )
Summary
Python source code
# Create image of Ulam spiral
SIZE = 201 # image size (must be odd)
P = [ 0 ] * ( SIZE * SIZE + 1 )
for C in range ( 2 , len ( P )):
if P [ C ] == 0 :
#print(C)
for x in range ( 2 , len ( P )):
z = x * C
if z >= len ( P ):
break
P [ z ] = 1
cdir = 0
dirs = [( 1 , 0 ), ( 0 , - 1 ), ( - 1 , 0 ), ( 0 , 1 )]
out = [[ "0" ] * SIZE for y in range ( SIZE )]
px , py = SIZE // 2 , SIZE // 2
nstep = []
cstep = 1
for x in range ( SIZE * SIZE ):
nstep . append ( cstep )
nstep . append ( cstep )
cstep += 1
cstep = nstep . pop ( 0 )
for p in range ( SIZE * SIZE ):
if p > 0 and P [ p + 1 ] == 0 :
out [ py ][ px ] = "1"
px += dirs [ cdir % 4 ][ 0 ]
py += dirs [ cdir % 4 ][ 1 ]
cstep -= 1
if cstep == 0 :
cdir += 1
cstep = nstep . pop ( 0 )
# Save image in NetPBM bitmap format
f = open ( "ulam.pbm" , "w" )
f . write ( f "P1 \n { SIZE } { SIZE } \n " )
for y in range ( SIZE ):
f . write ( '' . join ( out [ y ]) + " \n " )
f . close ()
# Convert PBM to PNG with ImageMagick (and increase resolution 10x):
# mogrify -format png -interpolate Nearest -filter point -resize 1000% ulam.pbm
Licensing
I, the copyright holder of this work, hereby publish it under the following license:
This file is made available under the Creative Commons CC0 1.0 Universal Public Domain Dedication .
The person who associated a work with this deed has dedicated the work to the public domain by waiving all of their rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law. You can copy, modify, distribute and perform the work, even for commercial purposes, all without asking permission.
http://creativecommons.org/publicdomain/zero/1.0/deed.en CC0 Creative Commons Zero, Public Domain Dedication false false
English Add a one-line explanation of what this file represents
File history
Click on a date/time to view the file as it appeared at that time.
Date/Time Thumbnail Dimensions User Comment
current 10:38, 17 April 2023 2,010 × 2,010 (8 KB) Morn Uploaded own work with UploadWizard
File usage
The following pages on the English Wikipedia use this file (pages on other projects are not listed):
Global file usage
The following other wikis use this file:
Usage on ary.wiki.x.io
Usage on en.wiktionary.org
This file contains additional information, probably added from the digital camera or scanner used to create or digitize it.
If the file has been modified from its original state, some details may not fully reflect the modified file.