Uncertainty in Wumpus world

uncertain_wumpus.py

from sys import argv

width = 0
height = 0

def loadMap(filename):
    with open(filename, 'r') as f:
        global width
        global height
        height, width = [int(x) for x in f.readline().split()]
        p = float(f.readline())
        loadedMap = []
        for lineNumber in range(0, height): 
            loadedMap.append(f.readline().split()[0])
        return p, loadedMap

def clearImproperIndices(x):
    return not((x[1] == width) or (x[0] == height) or (-1 in x))

def getFrontIndices(fieldMap, probTable):

    # if unknown field is next to visited, it means it can't go to front
    for i in range(0, height):
        for j in range(0, width):
            if (fieldMap[i][j] == 'O'):
                neighbours = ((i, j - 1), (i, j + 1), (i - 1, j), (i + 1, j))
                for coords in filter(clearImproperIndices, neighbours):
                    if fieldMap[coords[0]][coords[1]] == '?':
                        fieldMap[coords[0]] = fieldMap[coords[0]][:coords[1]] + '|' + fieldMap[coords[0]][coords[1] + 1:]
                        probTable[coords[0]][coords[1]][0] = 0.0

    # connections is a list of fields where at least one has to be a hole
    connections = []
    front = set()
    for i in range(0, height):
        for j in range(0, width):
            if (fieldMap[i][j] == 'B'):
                neighbours = ((i, j - 1), (i, j + 1), (i - 1, j), (i + 1, j))
                fieldsAroundSameBreeze = []
                for coords in filter(clearImproperIndices, neighbours):
                    if fieldMap[coords[0]][coords[1]] == '?':
                        fieldsAroundSameBreeze.append(probTable[coords[0]][coords[1]])
                        front.add((coords[0], coords[1]))
                if len(fieldsAroundSameBreeze):
                    connections.append(tuple(fieldsAroundSameBreeze))
    # iterate over set to get references
    front = tuple([probTable[coords[0]][coords[1]], [0.0], [0.0]] for coords in front)

    for i in range(0, height):
        fieldMap[i] = fieldMap[i].replace('|', '?')

    fieldMap = tuple(fieldMap)

    return front, connections

if (len(argv) != 3):
    raise Exception('Too few arguments!')

prob, fieldMap = loadMap(argv[1])
probTable = tuple([[prob] for j in i] for i in fieldMap)

front, connections = getFrontIndices(fieldMap, probTable)


def checkNextField(index):
    for pr in [prob, 1 - prob]:
        front[index][0][0] = pr

        if front[index][0][0] == 1 - prob:
            for con in connections:
                if not([0.0] in con) and not([prob] in con):
                    front[index][0][0] = 0.0
                    return

        # our path in tree is valid - we are in last node
        if (index == len(front) - 1):
            sum = front[0][0][0]
            for field in front[1:]:
                sum *= field[0][0]
            for field in front:
                i = 1 if field[0][0] == prob else 2
                field[i][0] += sum
        else:
            checkNextField(index + 1)
    front[index][0][0] = 0.0


if len(front) > 0:
    checkNextField(0)

for field in front:
    field[0][0] = field[1][0] / (field[1][0] + field[2][0])


line = ''
for i in range(0, height):
    for j in range(0, width):
        if (fieldMap[i][j] in ('B', 'O')):
            probTable[i][j][0] = 0.0
        line += format(probTable[i][j][0], '.2f') + ' '
    line = line[:-1] + '\n'

with open(argv[2], 'w') as f:
    f.write(line[:-1])