How can I iterate over a function

Question

I'm simulating forest-fire, and one of my tasks is to plot the density of trees vs those currently burning and empty plots. I have the disparate parts, however I need assistance in putting them together as I can't work out how to put my code together. Currently, I have my initial conditions

p, f = 0.5, 0.3
nx, ny = 100, 100
X = np.zeros((ny, nx))
adjacent = ((-1,0), (0,-1), (0, 1), (1,0))
E, T, F = 0, 1, 2
xvalues = [0]
yvalues = [0]

my function that generates the next frame (distribution of fire) is

    def iterate(X):

    Xnew = np.zeros((ny, nx))
    for ix in range(1,nx-1):
        for iy in range(1,ny-1):
            if X[iy,ix] == E and np.random.random() <= p:
                Xnew[iy,ix] = T
            if X[iy,ix] == T:
                Xnew[iy,ix] = T
                for dx,dy in adjacent:
                    if X[iy+dy,ix+dx] == F:
                        Xnew[iy,ix] = F
                else:
                    if np.random.random() <= f:
                        Xnew[iy,ix] = F                    
    return Xnew
    print(Xnew)

The bit I'm struggling with is how to write the following correctly with the above material so that I could go up to Xn where n is about 1000

X1 = iterate(X)
X2 = iterate(X1)
X3 = iterate(X2) and so on

and for each iteration calculate

num_empty = (Xn == 0).sum()
num_tree = (Xn == 1).sum()
num_fire = (Xn == 2).sum()
density = num_tree/(num_fire+num_empty)

xvalues.append(i)
yvalues.append(density)


print(density)

Any help would be appreciated!

score 0 · Answer 1 · answered Oct 01 '22 at 05:25

I think you need to iterate over the range of n ints rather than "function".

i = 0
_X = iteration(X)
num_empty = (_X == 0).sum()
num_tree = (_X == 1).sum()
num_fire = (_X == 2).sum()
density = num_tree / (num_fire + num_empty)
print(i, density)
xvalues.append(i)
yvalues.append(density)
n = 1000
for i in range(1, n):
    _X = iteration(_X)
    num_empty = (_X == 0).sum()
    num_tree = (_X == 1).sum()
    num_fire = (_X == 2).sum()
    density = num_tree / (num_fire + num_empty)
    print(i, density)
    xvalues.append(i)
    yvalues.append(density)

Your answer could be improved with additional supporting information. Please [edit] to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers [in the help center](/help/how-to-answer). — Community, Oct 05 '22 at 01:13

How can I iterate over a function

1 Answers1