#MonthOfCode day 8 - mathematics

day_8.py

import random
import sys # for exit function
import time
import pygame
from pygame import Rect

#   DEFINITIONS
################################################
DISP_COLOR=(230, 190, 230) #gray with a violet touch
PREDEF_RADIUS = 8
PREDEF_L_WIDTH = 2
NB_MAX_NODES = 12

CELL_PX_SIZE = 32
NB_CELLS_ROW = 16

def displayNode( matr_x, matr_y ):
    nx,ny = ( matr_x*CELL_PX_SIZE, matr_y*CELL_PX_SIZE )
    pygame.draw.circle(window, DISP_COLOR,
        (nx,ny), PREDEF_RADIUS, PREDEF_L_WIDTH)


#   MAIN PART
################################################

# init. pygame libr; create the screen and diplays a help message in the console
pygame.init() 
window = pygame.display.set_mode((CELL_PX_SIZE*NB_CELLS_ROW, CELL_PX_SIZE*NB_CELLS_ROW))

# init. a boolean matrix; this aims at representing nodes of a random graph
cnt_nodes = 0
bool_matr = list()
coord_nodes = list()
for i in xrange(NB_CELLS_ROW ):
    line = list()
    for j in xrange( NB_CELLS_ROW):
        if( cnt_nodes > NB_MAX_NODES or j<2 or j>(NB_CELLS_ROW-2) or i<2 or i>(NB_CELLS_ROW-2)  ):
            line.append( False  )
            continue
        if( random.choice( range(16))==0  ):
            line.append( True)
            coord_nodes.append( (i,j) )
            cnt_nodes +=1
        else:
            line.append( False)
    bool_matr.append(line)

# random edges
assoc_matr = dict()
for i in xrange( cnt_nodes):
    for j in xrange(cnt_nodes):
        if j>=i:
            continue
        assoc_matr[ (i,j) ] = True if (random.choice(range(4))==0 ) else False

# diplays nodes
for i in xrange(NB_CELLS_ROW ):
    for j in xrange( NB_CELLS_ROW):
        if( bool_matr[j][i] ):
            displayNode(j, i)
# diplays edges
for nodes_pair in assoc_matr:
    if( assoc_matr[ nodes_pair ] ): # the two nodes are linked
        x1,y1 = coord_nodes[ nodes_pair[0] ]
        x2,y2 = coord_nodes[ nodes_pair[1] ]
        pygame.draw.line(window, DISP_COLOR,
            (x1*CELL_PX_SIZE,y1*CELL_PX_SIZE),
            (x2*CELL_PX_SIZE,y2*CELL_PX_SIZE)  )

#draw it to the screen
pygame.display.flip() 
while True: 
    for event in pygame.event.get(): 
        if event.type == pygame.QUIT: 
            sys.exit(0) 
    time.sleep(0.1)

generates and displays random graphs, screenshot available on twitter @spartangeek