Exemples d'implémentation d'algorithmes avec dask¶

Nombres premiers¶

Voici un exemple d'implémentation d'un algorithme pour trouver les nombres premiers jusqu'à un certain nombre n en utilisant Dask.

In [5]:

from dask.distributed import Client
client = Client()

from dask.distributed import Client client = Client()

In [ ]:

client.close()

client.close()

In [ ]:

client.dashboard_link

client.dashboard_link

In [40]:

import time

def is_prime(x):
    for i in range(2, x // 2):
      if x % i == 0:
        return None
    return x

def launch(n):
  print(f"running for {n}")
  input = range(3, n)
  start = time.perf_counter()
  results = [x for x in input if is_prime(x) != None]
  end = time.perf_counter()
  print(f"Single threaded time: {end - start:.6f} seconds")

  start = time.perf_counter()
  futures = client.map(is_prime, input)
  results = client.gather(futures)
  end = time.perf_counter()
  print(f"Dask time: {end - start:.6f} seconds")

launch(100)
launch(10000)

import time def is_prime(x): for i in range(2, x // 2): if x % i == 0: return None return x def launch(n): print(f"running for {n}") input = range(3, n) start = time.perf_counter() results = [x for x in input if is_prime(x) != None] end = time.perf_counter() print(f"Single threaded time: {end - start:.6f} seconds") start = time.perf_counter() futures = client.map(is_prime, input) results = client.gather(futures) end = time.perf_counter() print(f"Dask time: {end - start:.6f} seconds") launch(100) launch(10000)

running for 100
Single threaded time: 0.000031 seconds
Dask time: 0.059348 seconds
running for 10000
Single threaded time: 0.099690 seconds
Dask time: 5.287371 seconds

Encodage César de niveau 1 qui incrémente chaque lettre de l'alphabet d'une position. Par exemple, "abc" deviendrait "bcd". Faire aussi le décodage inverse.

In [19]:

def encode(c):
    if c == "z":
       return "a"
    return chr(ord(c) + 1)

def decode(c):
    if c == "a":
       return "z"
    return chr(ord(c) - 1)

input = "azhello"
futures = client.map(encode, input)
encoded = client.gather(futures)

print(encoded, "".join(encoded))


futures = client.map(decode, encoded)
output = client.gather(futures)

print("".join(output))

print("input equal to decoded ?", input == "".join(output))

def encode(c): if c == "z": return "a" return chr(ord(c) + 1) def decode(c): if c == "a": return "z" return chr(ord(c) - 1) input = "azhello" futures = client.map(encode, input) encoded = client.gather(futures) print(encoded, "".join(encoded)) futures = client.map(decode, encoded) output = client.gather(futures) print("".join(output)) print("input equal to decoded ?", input == "".join(output))

['b', 'a', 'i', 'f', 'm', 'm', 'p'] baifmmp
azhello
input equal to decoded ? True

Faire la partie 1 du day 4 de advent of code 2025. Trouver les cases qui ont moins de 4 @ dans les cases adjacentes.

In [39]:

input = """
..@@.@@@@.
@@@.@.@.@@
@@@@@.@.@@
@.@@@@..@.
@@.@@@@.@@
.@@@@@@@.@
.@.@.@.@@@
@.@@@.@@@@
.@@@@@@@@.
@.@.@@@.@.
"""

lines = input.split()
print("lines", lines)
line_count = len(lines)
col_count = len(lines[0])

def count_rolls(index):
    line = index[0]
    col = index[1]
    if lines[line][col] != "@":
        return (index, 10)
    count = 0
    for i in range(line - 1, line + 2):
        for j in range(col - 1, col + 2):
            if (i, j) != (line, col) and 0 <= i < line_count and 0 <= j < col_count and lines[i][j] == "@":
                count += 1
    return (index, count)

# Produit cartésien
indices = [(x, y) for x in range(line_count) for y in range(col_count)]
print(indices)

futures = client.map(count_rolls, indices)
output = client.gather(futures)
print(output)
result = [x for x in output if x[1] < 4]
print(len(result), result)

input = """ ..@@.@@@@. @@@.@.@.@@ @@@@@.@.@@ @.@@@@..@. @@.@@@@.@@ .@@@@@@@.@ .@.@.@.@@@ @.@@@.@@@@ .@@@@@@@@. @.@.@@@.@. """ lines = input.split() print("lines", lines) line_count = len(lines) col_count = len(lines[0]) def count_rolls(index): line = index[0] col = index[1] if lines[line][col] != "@": return (index, 10) count = 0 for i in range(line - 1, line + 2): for j in range(col - 1, col + 2): if (i, j) != (line, col) and 0 <= i < line_count and 0 <= j < col_count and lines[i][j] == "@": count += 1 return (index, count) # Produit cartésien indices = [(x, y) for x in range(line_count) for y in range(col_count)] print(indices) futures = client.map(count_rolls, indices) output = client.gather(futures) print(output) result = [x for x in output if x[1] < 4] print(len(result), result)

lines ['..@@.@@@@.', '@@@.@.@.@@', '@@@@@.@.@@', '@.@@@@..@.', '@@.@@@@.@@', '.@@@@@@@.@', '.@.@.@.@@@', '@.@@@.@@@@', '.@@@@@@@@.', '@.@.@@@.@.']
[(0, 0), (0, 1), (0, 2), (0, 3), (0, 4), (0, 5), (0, 6), (0, 7), (0, 8), (0, 9), (1, 0), (1, 1), (1, 2), (1, 3), (1, 4), (1, 5), (1, 6), (1, 7), (1, 8), (1, 9), (2, 0), (2, 1), (2, 2), (2, 3), (2, 4), (2, 5), (2, 6), (2, 7), (2, 8), (2, 9), (3, 0), (3, 1), (3, 2), (3, 3), (3, 4), (3, 5), (3, 6), (3, 7), (3, 8), (3, 9), (4, 0), (4, 1), (4, 2), (4, 3), (4, 4), (4, 5), (4, 6), (4, 7), (4, 8), (4, 9), (5, 0), (5, 1), (5, 2), (5, 3), (5, 4), (5, 5), (5, 6), (5, 7), (5, 8), (5, 9), (6, 0), (6, 1), (6, 2), (6, 3), (6, 4), (6, 5), (6, 6), (6, 7), (6, 8), (6, 9), (7, 0), (7, 1), (7, 2), (7, 3), (7, 4), (7, 5), (7, 6), (7, 7), (7, 8), (7, 9), (8, 0), (8, 1), (8, 2), (8, 3), (8, 4), (8, 5), (8, 6), (8, 7), (8, 8), (8, 9), (9, 0), (9, 1), (9, 2), (9, 3), (9, 4), (9, 5), (9, 6), (9, 7), (9, 8), (9, 9)]
[((0, 0), 10), ((0, 1), 10), ((0, 2), 3), ((0, 3), 3), ((0, 4), 10), ((0, 5), 3), ((0, 6), 3), ((0, 7), 4), ((0, 8), 3), ((0, 9), 10), ((1, 0), 3), ((1, 1), 6), ((1, 2), 6), ((1, 3), 10), ((1, 4), 4), ((1, 5), 10), ((1, 6), 4), ((1, 7), 10), ((1, 8), 5), ((1, 9), 4), ((2, 0), 4), ((2, 1), 7), ((2, 2), 6), ((2, 3), 7), ((2, 4), 5), ((2, 5), 10), ((2, 6), 2), ((2, 7), 10), ((2, 8), 4), ((2, 9), 4), ((3, 0), 4), ((3, 1), 10), ((3, 2), 6), ((3, 3), 7), ((3, 4), 7), ((3, 5), 6), ((3, 6), 10), ((3, 7), 10), ((3, 8), 4), ((3, 9), 10), ((4, 0), 3), ((4, 1), 5), ((4, 2), 10), ((4, 3), 7), ((4, 4), 8), ((4, 5), 7), ((4, 6), 5), ((4, 7), 10), ((4, 8), 4), ((4, 9), 3), ((5, 0), 10), ((5, 1), 4), ((5, 2), 6), ((5, 3), 5), ((5, 4), 7), ((5, 5), 6), ((5, 6), 6), ((5, 7), 5), ((5, 8), 10), ((5, 9), 4), ((6, 0), 10), ((6, 1), 4), ((6, 2), 10), ((6, 3), 6), ((6, 4), 10), ((6, 5), 5), ((6, 6), 10), ((6, 7), 6), ((6, 8), 7), ((6, 9), 4), ((7, 0), 2), ((7, 1), 10), ((7, 2), 6), ((7, 3), 6), ((7, 4), 6), ((7, 5), 10), ((7, 6), 6), ((7, 7), 7), ((7, 8), 7), ((7, 9), 4), ((8, 0), 10), ((8, 1), 5), ((8, 2), 5), ((8, 3), 7), ((8, 4), 6), ((8, 5), 7), ((8, 6), 6), ((8, 7), 7), ((8, 8), 5), ((8, 9), 10), ((9, 0), 1), ((9, 1), 10), ((9, 2), 3), ((9, 3), 10), ((9, 4), 4), ((9, 5), 5), ((9, 6), 4), ((9, 7), 10), ((9, 8), 2), ((9, 9), 10)]
13 [((0, 2), 3), ((0, 3), 3), ((0, 5), 3), ((0, 6), 3), ((0, 8), 3), ((1, 0), 3), ((2, 6), 2), ((4, 0), 3), ((4, 9), 3), ((7, 0), 2), ((9, 0), 1), ((9, 2), 3), ((9, 8), 2)]