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Diffstat (limited to 'bestflags/generation.py')
| -rw-r--r-- | bestflags/generation.py | 110 |
1 files changed, 92 insertions, 18 deletions
diff --git a/bestflags/generation.py b/bestflags/generation.py index 29be9685..1a0ad4c0 100644 --- a/bestflags/generation.py +++ b/bestflags/generation.py @@ -2,44 +2,118 @@ Part of the Chrome build flags optimization. -This module contains the core algorithm of producing the next generation of -execution. +This module contains the base generation class. This class contains the tasks of +this current generation. The generation will not evolve to the next generation +until all the tasks in this generation are done executing. It also contains a +set of tasks that could potentially be used to generate the next generation, +e.g., in the genetic algorithm, a set of good species will be kept to evolve to +the successive generations. For the hill climbing algorithm example, the +candidate_pool will contain a current task t being evaluated and the exe_pool +will contains all the task t's neighbor. """ __author__ = 'yuhenglong@google.com (Yuheng Long)' +class NoneOverridingError(Exception): + """Define an Exception class for subclasses not overriding certain methods.""" + pass + + class Generation(object): """A generation of a framework run. - This also contains the core implementation, reproducing new generations. + The base class of generation. Concrete subclasses, e.g., GAGeneration should + override the Next and Improve method to implement algorithm specific + applications. """ - def __init__(self, pool): + def __init__(self, exe_pool, candidate_pool): """Set up the tasks set of this generation. Args: - pool: a set of tasks to be run + exe_pool: A set of tasks to be run. + candidate_pool: A set of tasks to be considered to be used to generate the + next generation. """ - self._pool = pool - def Next(self): - """Calculate the next generation. + self._exe_pool = exe_pool + self._candidate_pool = candidate_pool + + # Keeping the record of how many tasks are pending. Pending tasks are the + # ones that have been sent out to the next stage for execution but have not + # finished. A generation is not ready for the reproduction of the new + # generations until all its pending tasks have been executed. + self._pending = len(exe_pool) + + def Pool(self): + """Return the task set of this generation.""" - This is the core of the framework implementation. + return self._exe_pool + + def Done(self): + """All the tasks in this generation are done. Returns: - A new generation. + True if all the tasks have been executed. That is the number of pending + task is 0. """ - def Pool(self): - """Return the task set of this generation.""" - pass + return self._pending == 0 + + def UpdateTask(self, task): + """Match a task t in this generation that is equal to the input task. + + This method is called when the input task has just finished execution. This + method finds out whether there is a pending task t in the current generation + that is the same as the input task. Two tasks are the same if their flag + options are the same. A task is pending if it has not been performed. + If there is a pending task t that matches the input task, task t will be + substituted with the input task in this generation. In that case, the input + task, as well as its build and test results encapsulated in the task, will + be stored in the current generation. These results could be used to produce + the next generation. + If there is a match, the current generation will have one less pending task. + When there is no pending task, the generation can be used to produce the + next generation. + The caller of this function is responsible for not calling this method on + the same task more than once. + + Args: + task: A task that has its results ready. + """ + + # If there is a match. + if task in self._exe_pool: + # Remove the place holder task in this generation and store the new input + # task and its result. + self._exe_pool.remove(task) + self._exe_pool.add(task) + + # The current generation will have one less task to wait on. + self._pending -= 1 + + assert self._pending >= 0 def Improve(self): - """True if this generation has improvement over its parent generation.""" - pass + """True if this generation has improvement over its parent generation. + + Raises: + NoneOverridingError: The subclass should override this method. + """ + raise NoneOverridingError('Must be implemented by child class') + + def Next(self): + """Calculate the next generation. + + This is the core of the framework implementation. It must be overridden by + the concrete subclass to implement algorithm specific generations. + + Returns: + A set of new generations. + + Raises: + NoneOverridingError: The subclass should override this method. + """ - def GetBest(self): - """Get the best flagset.""" - return self._pool[0] + raise NoneOverridingError('Must be implemented by child class') |