Discussion :

[Invité]

Bonjour,

Je suis débutante en python et j'aimerais savoir ce que font exactement les fonctions des programmes suivants :

def makeTSP(nCities)
positions = 2*random.rand(nCities,2)-1;
distances = zeros((nCities,nCities))

for i in range(nCities):
for j in range(i+1,nCities):
distances[i,j] = sqrt((positions[i,0] - positions[j,0])**2 + (positions[i,1] - positions[j,1])**2);
distances[j,i] = distances[i,j];

return distances

def greedy(distances):
nCities = shape(distances)[0]
distanceTravelled = 0

# Need a version of the matrix we can trash
dist = distances.copy()

cityOrder = zeros(nCities)
cityOrder[0] = random.randint(nCities)
dist[:,cityOrder[0]] = Inf

for i in range(nCities-1):
cityOrder[i+1] = argmin(dist[cityOrder[i],:])
distanceTravelled += dist[cityOrder[i],cityOrder[i+1]]
# Now exclude the chance of travelling to that city again
dist[:,cityOrder[i+1]] = Inf

# Now return to the original city
distanceTravelled += distances[cityOrder[nCities-1],0]

return cityOrder, distanceTravelled

c'est à dire les fonctions random.rand, zeros, range, shape, rand.int, le remplissage de matrice etc...

Cordialement

[fred1599]

Merci de mettre votre code avec les balises prévues à cet effet ( balise en haut à droite # )

Sinon le code est illisible !

[VinsS]

Salut,

...
c'est à dire les fonctions random.rand, zeros, range, shape, rand.int, le remplissage de matrice etc...

Mais c'est simple:

random.randint(a, b): Return a random integer N such that a <= N <= b. Alias for randrange(a, b+1).

range(start, stop[, step]): The arguments to the range constructor must be integers (either built-in int or any object that implements the __index__ special method). If the step argument is omitted, it defaults to 1. If the start argument is omitted, it defaults to 0. If step is zero, ValueError is raised.
For a positive step, the contents of a range r are determined by the formula r[i] = start + step*i where i >= 0 and r[i] < stop.
For a negative step, the contents of the range are still determined by the formula r[i] = start + step*i, but the constraints are i >= 0 and r[i] > stop.
A range object will be empty if r[0] does not meet the value constraint. Ranges do support negative indices, but these are interpreted as indexing from the end of the sequence determined by the positive indices.
Ranges containing absolute values larger than sys.maxsize are permitted but some features (such as len()) may raise OverflowError.

zeros, shape: voir dans le code source.

rand.int: non, randint, voir plus haut.

le remplissage de matrice: ??

Je te propose de commencer par le début: http://python.developpez.com/cours/apprendre-python3/