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Compute the first element for the greedy algorithm

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coolneng 2021-03-22 19:36:47 +01:00
parent 8b72d3f01c
commit 27f3baca07
Signed by: coolneng
GPG Key ID: 9893DA236405AF57
1 changed files with 25 additions and 4 deletions
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29
src/processing.py
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@ -1,6 +1,5 @@
from preprocessing import parse_file from preprocessing import parse_file
from pandas import DataFrame from pandas import DataFrame, Series
from secrets import randbelow
from sys import argv from sys import argv
@ -8,16 +7,37 @@ def get_furthest_element(element, data):
element_df = data.query(f"source == {element} or destination == {element}") element_df = data.query(f"source == {element} or destination == {element}")
furthest_index = element_df["distance"].idxmax() furthest_index = element_df["distance"].idxmax()
furthest_row = data.iloc[furthest_index] furthest_row = data.iloc[furthest_index]
print(furthest_row)
return furthest_row
def get_first_solution(n, data):
distance_sum = DataFrame(columns=["point", "distance"])
for element in range(n):
element_df = data.query(f"source == {element} or destination == {element}")
distance = element_df["distance"].sum()
distance_sum = distance_sum.append(
{"point": element, "distance": distance}, ignore_index=True
)
furthest_index = distance_sum["distance"].idxmax()
furthest_row = distance_sum.iloc[furthest_index]
return furthest_row return furthest_row
def greedy_algorithm(n, m, data): def greedy_algorithm(n, m, data):
solutions = DataFrame(columns=["source", "destination", "distance"]) solutions = DataFrame(columns=["point", "distance"])
first_solution = get_first_solution(n, data)
solutions = solutions.append(first_solution, ignore_index=True)
for _ in range(m): for _ in range(m):
centroid = get_furthest_element(element=randbelow(n), data=data) centroid = solutions.apply(get_furthest_element, 1, data)
solutions = solutions.append(centroid) solutions = solutions.append(centroid)
# NOTE In each step, switch the element that gives the least amount
def local_search():
pass
def usage(argv): def usage(argv):
print(f"Usage: python {argv[0]} <file>") print(f"Usage: python {argv[0]} <file>")
exit(1) exit(1)
@ -27,6 +47,7 @@ def main():
if len(argv) != 2: if len(argv) != 2:
usage(argv) usage(argv)
n, m, data = parse_file(argv[1]) n, m, data = parse_file(argv[1])
greedy_algorithm(n, m, data)
if __name__ == "__main__": if __name__ == "__main__":