BPP (complexity)

BPP (complexity)

In computational complexity theory, BPP, which stands for bounded-error probabilistic polynomial time is the class of decision problems solvable by a probabilistic Turing machine in polynomial time, with an error probability of at most 1/3 for all instances.

BPP algorithm (1 run)
Answer produced
Correct
answer
YES NO
YES ≥ 2/3 ≤ 1/3
NO ≤ 1/3 ≥ 2/3
BPP algorithm (k runs)
Answer produced
Correct
answer
YES NO
YES > 1 − 2−ck < 2−ck
NO < 2−ck > 1 − 2−ck
for some constant c > 0

Informally, a problem is in BPP if there is an algorithm for it that has the following properties:

  • It is allowed to flip coins and make random decisions
  • It is guaranteed to run in polynomial time
  • On any given run of the algorithm, it has a probability of at most 1/3 of giving the wrong answer, whether the answer is YES or NO.

Read more about BPP (complexity):  Introduction, Definition, Problems, Related Classes, Complexity-theoretic Properties, Derandomization