[Tutor] More trouble debugging my game of life program

[Matt Smith]

Hi,

I've got my program working correctly (or so it seems) with my original
data file (r-pentomino.txt - attached) but when I run it with a larger
(30*30) file (big-r-pentomino - also attached) in an attempt to make it
work with out so many edge effects it returns the following error
message:

Traceback (most recent call last):
  File "Python/game_of_life/life.py", line 75, in <module>
    curses.wrapper(main)
  File "curses/wrapper.py", line 44, in wrapper
  File "Python/game_of_life/life.py", line 60, in main
    draw_board(matrix, stdscr, generation)
  File "Python/game_of_life/life.py", line 28, in draw_board
    stdscr.addch(y + 1, x + 1, ' ')
_curses.error: addch() returned ERR

I thought I had designed the program to work with any text file as long
as the lines are all the same length so I cannot understand why I get
this error message. When I read through the code I cannot see a reason
why the program should work for one size file and not another. The part
of the program that is failing is just drawing a space character at a
particular location on the screen.

Here is the listing of the program that I have also attached:

#! /usr/bin/env python

# Curses based Game of Life program
# Written by Matt Smith

import curses
from copy import deepcopy

def read_start():
    # Read the starting configuration from a text file
    file = open('/home/matt/Python/game_of_life/r-pentomino.txt', 'r')
    matrix = []
    for line in file:
        line = line.rstrip('\n')
        line_list=[]
        for i in range(len(line)):
            line_list.append(int(line[i]))
        matrix.append(line_list)
    return matrix

def draw_board(matrix, stdscr, generation):
    # Draw the life board based on the matrix containing the current
state
    for x in range(len(matrix[0])):
        for y in range(len(matrix)):
            if matrix[y][x]:
                stdscr.addch(y + 1, x + 1, '*')
            else:
                stdscr.addch(y + 1, x + 1, ' ')
    stdscr.addstr(len(matrix) + 1, 0, 'Generation: %s' % (generation))
    stdscr.refresh()

def update_matrix(matrix):
    matrix_updated = deepcopy(matrix)
    # Perform check for each value in the matrix
    for x in range(len(matrix[0])):
        for y in range(len(matrix)):
            neighbour_count = 0
            for n in (x-1, x, x+1):
                for m in (y-1, y, y+1):
                    try:
                        if matrix[m][n]:
                            if (n,m) != (x,y):
                                neighbour_count = neighbour_count + 1
                    except IndexError:
                        pass
            # Apply game of life rules to each item in the matrix
            if neighbour_count < 2:
                matrix_updated[y][x] = 0
            elif neighbour_count > 3:
                matrix_updated[y][x] = 0
            elif neighbour_count == 3:
                matrix_updated[y][x] = 1
            # No need to change value if neighbour count == 2
    return matrix_updated

def main(stdscr):
    # Initialise some variables and put the screen in it's starting
configuration
    matrix = read_start()
    generation = 1
    draw_board(matrix, stdscr, generation)
    stdscr.addstr(len(matrix) + 2, 0, 
        'Press <space> to advance a generation, <q> to quit.')
    # The main program loop - respond to keyboard input
    while 1:
        key_press = stdscr.getkey()
        if key_press == 'q':
            break
        elif key_press == ' ':
            generation = generation + 1
            matrix = update_matrix(matrix)
            draw_board(matrix, stdscr, generation)

# Run the main program inside the curses wrapper to ensure it leaves the
screen
# in a usable state
curses.wrapper(main)

Can anyone come up with the reason why one input file works and the
other one doesn't??

Thanks,

Matt
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