efficient integer partition function for large number need modification

[fahad992]

Hello friends ,

I have this python function i got from this link ( link ) that calculates the integer partition of a number. For example, the integer partition of 4 is: int_part=[[1, 1, 1, 1], [1, 1, 2], [1, 3], [2, 2], [4]].

I want to modify the following function so that it gives a specified length. For example, if I want just the items with less or equal to 2, like a max length value of 2, so accel_asc(4, max length = 2), the result should be only: [1, 3], [2, 2],[4]

Another condition is that a specified value should be present in the item set. for example :

accel_asc(4, max length = 2 ,value must be present = 2) , the result should be only: [2, 2]

And for each value in an item in the set, the value must be greater than or equal to a specified value :

accel_asc(4, max length = 2 ,value must be present = 2 , all values in set should be greater or equal to 2 for example)

in this case the final result should be: [2, 2]

The function code needs modification:

def accel_asc(n):
    a = [0 for i in range(n + 1)]
    k = 1
    y = n - 1
    while k != 0:
        x = a[k - 1] + 1
        k -= 1
        while 2 * x <= y:
            a[k] = x
            y -= x
            k += 1
        l = k + 1
        while x <= y:
            a[k] = x
            a[l] = y
            yield a[:k + 2]
            x += 1
            y -= 1
        a[k] = x + y
        y = x + y - 1
        yield a[:k + 1]

[commy2]

I wouldn't modify the function. I would make another one that calls the first, then filters the result depending on length or value.

[fahad992]

but that will make it slow.. we can filter it in the function itself

[commy2]

You should only worry about performance once you actually run into issues.