major refactoring

With the focus on (re)usability.
That includes adding separate modules for plotting, input generation
and things like that.

14 files changed, 349 insertions, 99 deletions

diff --git a/algorithms/algorithm.py b/algorithms/algorithm.py
index 322a51f..b65ed04 100644
--- a/algorithms/algorithm.py
+++ b/algorithms/algorithm.py
@@ -2,24 +2,22 @@
 # This file is licensed under the terms of the MIT License.
 # See LICENSE.txt for details.
 
+from . import inputgen
+
 class Algorithm:
     def __init__(self, codename, display_name, f):
-        self._codename = codename
-        self._display_name = display_name
-        self._f = f
-
-    def get_codename(self):
-        return self._codename
-
-    def get_display_name(self):
-        return self._display_name
+        self.codename = codename
+        self.display_name = display_name
+        self.function = f
 
-    def get_function(self):
-        return self._f
-
-    def __str__(self):
-        return self.get_display_name()
+    @staticmethod
+    def gen_input(n, case=inputgen.InputKind.AVERAGE):
+        #raise NotImplementedError('inputgen generation is not defined for generic algorithms')
+        return inputgen.gen_input_for_sorting(n, case)
 
 class SortingAlgorithm(Algorithm):
     def __init__(self, codename, display_name, f):
         super().__init__(codename, display_name, f)
+
+    def gen_input(self, n, case=inputgen.InputKind.AVERAGE):
+        return inputgen.gen_input_for_sorting(n, case)
diff --git a/algorithms/impl/__init__.py b/algorithms/impl/__init__.py
index 29cd51c..dcb8fc4 100644
--- a/algorithms/impl/__init__.py
+++ b/algorithms/impl/__init__.py
@@ -2,18 +2,16 @@
 # This file is licensed under the terms of the MIT License.
 # See LICENSE.txt for details.
 
-_ALL_ALGORITHMS = {}
+from importlib import import_module
+import os.path
+from pkgutil import iter_modules
 
-def _refresh_algorithms():
-    _ALGORITHMS_NAME = '_ALGORITHMS'
-    global _ALL_ALGORITHMS
-    _ALL_ALGORITHMS = {}
+from .. import algorithm
 
-    from algorithms.algorithm import Algorithm
+_ALGORITHMS_NAME = '_ALGORITHMS'
 
-    from importlib import import_module
-    import os.path
-    from pkgutil import iter_modules
+def refresh_algorithms():
+    all_algorithms = {}
 
     for _, module_name, is_pkg in iter_modules([os.path.dirname(__file__)]):
         if is_pkg:
@@ -21,9 +19,9 @@ def _refresh_algorithms():
         module = import_module('.' + module_name, __package__)
         if hasattr(module, _ALGORITHMS_NAME):
             module_algorithms = getattr(module, _ALGORITHMS_NAME)
-            for algorithm in module_algorithms:
-                assert isinstance(algorithm, Algorithm)
-                assert algorithm.get_codename() not in _ALL_ALGORITHMS
-                _ALL_ALGORITHMS[algorithm.get_codename()] = algorithm
+            for descr in module_algorithms:
+                assert isinstance(descr, algorithm.Algorithm)
+                assert descr.codename not in all_algorithms
+                all_algorithms[descr.codename] = descr
 
-_refresh_algorithms()
+    return all_algorithms
diff --git a/algorithms/impl/bubble_sort.py b/algorithms/impl/bubble_sort.py
index 2abfc43..e6aa645 100644
--- a/algorithms/impl/bubble_sort.py
+++ b/algorithms/impl/bubble_sort.py
@@ -2,6 +2,10 @@
 # This file is licensed under the terms of the MIT License.
 # See LICENSE.txt for details.
 
+import sys
+
+from ..algorithm import SortingAlgorithm
+
 def bubble_sort(xs):
     while True:
         swapped = False
@@ -14,7 +18,7 @@ def bubble_sort(xs):
     return xs
 
 def bubble_sort_optimized(xs):
-    n  = len(xs)
+    n = len(xs)
     while True:
         new_n = 0
         for i in range(1, n):
@@ -26,14 +30,18 @@ def bubble_sort_optimized(xs):
             break
     return xs
 
-if __name__ == '__main__':
-    import sys
-    xs = list(map(int, sys.argv[1:]))
+_ALGORITHMS = [
+    SortingAlgorithm('bubble_sort', 'Bubble sort', bubble_sort),
+    SortingAlgorithm('bubble_sort_optimized', 'Bubble sort (optimized)', bubble_sort_optimized),
+]
+
+def _parse_args(args=sys.argv):
+    return list(map(int, args[1:]))
+
+def main(args=sys.argv):
+    xs = _parse_args(args)
     print(bubble_sort(list(xs)))
     print(bubble_sort_optimized(list(xs)))
-else:
-    from algorithms.algorithm import SortingAlgorithm
-    _ALGORITHMS = [
-        SortingAlgorithm('bubble_sort', 'Bubble sort', bubble_sort),
-        SortingAlgorithm('bubble_sort_optimized', 'Bubble sort (optimized)', bubble_sort_optimized),
-    ]
+
+if __name__ == '__main__':
+    main()
diff --git a/algorithms/impl/heapsort.py b/algorithms/impl/heapsort.py
index db3b6bd..c92a04c 100644
--- a/algorithms/impl/heapsort.py
+++ b/algorithms/impl/heapsort.py
@@ -2,6 +2,10 @@
 # This file is licensed under the terms of the MIT License.
 # See LICENSE.txt for details.
 
+import sys
+
+from ..algorithm import SortingAlgorithm
+
 # Disclaimer: implemented in the most literate way.
 
 def heapsort(xs):
@@ -49,11 +53,16 @@ def _siftdown(xs, start, end):
         else:
             break
 
+_ALGORITHMS = [
+    SortingAlgorithm('heapsort', 'Heapsort', heapsort),
+]
+
+def _parse_args(args=sys.argv):
+    return list(map(int, args[1:]))
+
+def main(args=sys.argv):
+    xs = _parse_args(args)
+    print(heapsort(list(xs)))
+
 if __name__ == '__main__':
-    import sys
-    print(heapsort(list(map(int, sys.argv[1:]))))
-else:
-    from algorithms.algorithm import SortingAlgorithm
-    _ALGORITHMS = [
-        SortingAlgorithm('heapsort', 'Heapsort', heapsort),
-    ]
+    main()
diff --git a/algorithms/impl/insertion_sort.py b/algorithms/impl/insertion_sort.py
index f671712..006ab66 100644
--- a/algorithms/impl/insertion_sort.py
+++ b/algorithms/impl/insertion_sort.py
@@ -2,6 +2,10 @@
 # This file is licensed under the terms of the MIT License.
 # See LICENSE.txt for details.
 
+import sys
+
+from ..algorithm import SortingAlgorithm
+
 def insertion_sort(xs):
     for i in range(1, len(xs)):
         j = i
@@ -10,11 +14,16 @@ def insertion_sort(xs):
             j -= 1
     return xs
 
+_ALGORITHMS = [
+    SortingAlgorithm('insertion_sort', 'Insertion sort', insertion_sort),
+]
+
+def _parse_args(args=sys.argv):
+    return list(map(int, args[1:]))
+
+def main(args=sys.argv):
+    xs = _parse_args(args)
+    print(insertion_sort(list(xs)))
+
 if __name__ == '__main__':
-    import sys
-    print(insertion_sort(list(map(int, sys.argv[1:]))))
-else:
-    from algorithms.algorithm import SortingAlgorithm
-    _ALGORITHMS = [
-        SortingAlgorithm('insertion_sort', 'Insertion sort', insertion_sort),
-    ]
+    main()
diff --git a/algorithms/impl/median.py b/algorithms/impl/median.py
index ba51c71..e6b9901 100644
--- a/algorithms/impl/median.py
+++ b/algorithms/impl/median.py
@@ -2,9 +2,11 @@
 # This file is licensed under the terms of the MIT License.
 # See LICENSE.txt for details.
 
-from algorithms.impl.quicksort import quicksort_random
+from heapq import heappush, heappop
+import sys
 
-from heapq import *
+from ..algorithm import Algorithm
+from .quicksort import quicksort_random
 
 def calc_median_heaps(xs):
     cur_median = 0.0
@@ -30,7 +32,7 @@ def calc_median_heaps(xs):
             cur_median = min_heap[0]
     return cur_median
 
-def calc_median_sort_first(xs):
+def calc_median_sorting(xs):
     if not xs:
         return 0.0
     quicksort_random(xs)
@@ -39,14 +41,18 @@ def calc_median_sort_first(xs):
     else:
         return xs[len(xs) // 2 - 1] / 2 + xs[len(xs) // 2] / 2
 
-if __name__ == '__main__':
-    import sys
-    xs = list(map(int, sys.argv[1:]))
-    print(calc_median_sort_first(list(xs)))
+_ALGORITHMS = [
+    Algorithm('median_sorting', 'Median value (using explicit sorting)', calc_median_sorting),
+    Algorithm('median_heaps', 'Median value (using heaps)', calc_median_heaps),
+]
+
+def _parse_args(args=sys.argv):
+    return list(map(int, args[1:]))
+
+def main(args=sys.argv):
+    xs = _parse_args(args)
+    print(calc_median_sorting(list(xs)))
     print(calc_median_heaps(list(xs)))
-else:
-    from algorithms.algorithm import Algorithm
-    _ALGORITHMS = [
-        Algorithm('median_sort_first', 'Median (input is sorted first)', calc_median_sort_first),
-        Algorithm('median_heaps', 'Median (using heaps)', calc_median_heaps),
-    ]
+
+if __name__ == '__main__':
+    main()
diff --git a/algorithms/impl/merge_sort.py b/algorithms/impl/merge_sort.py
index 9fa96ec..8d0b573 100644
--- a/algorithms/impl/merge_sort.py
+++ b/algorithms/impl/merge_sort.py
@@ -2,6 +2,10 @@
 # This file is licensed under the terms of the MIT License.
 # See LICENSE.txt for details.
 
+import sys
+
+from ..algorithm import SortingAlgorithm
+
 def merge(left, right):
     result = []
     l, r = 0, 0
@@ -24,11 +28,16 @@ def merge_sort(xs):
     mid = len(xs) // 2
     return merge(merge_sort(xs[:mid]), merge_sort(xs[mid:]))
 
+_ALGORITHMS = [
+    SortingAlgorithm('merge_sort', 'Merge sort', merge_sort),
+]
+
+def _parse_args(args=sys.argv):
+    return list(map(int, args[1:]))
+
+def main(args=sys.argv):
+    xs = _parse_args(args)
+    print(merge_sort(list(xs)))
+
 if __name__ == '__main__':
-    import sys
-    print(merge_sort(list(map(int, sys.argv[1:]))))
-else:
-    from algorithms.algorithm import SortingAlgorithm
-    _ALGORITHMS = [
-        SortingAlgorithm('merge_sort', 'Merge sort', merge_sort),
-    ]
+    main()
diff --git a/algorithms/impl/quicksort.py b/algorithms/impl/quicksort.py
index 32100b0..ddc8269 100644
--- a/algorithms/impl/quicksort.py
+++ b/algorithms/impl/quicksort.py
@@ -3,6 +3,9 @@
 # See LICENSE.txt for details.
 
 from random import randrange
+import sys
+
+from ..algorithm import SortingAlgorithm
 
 def _partition(xs, beg, end, select_pivot):
     pivot = select_pivot(xs, beg, end)
@@ -55,20 +58,24 @@ def quicksort_random(xs):
     _quicksort(xs, 0, len(xs) - 1, _select_random)
     return xs
 
-if __name__ == '__main__':
-    import sys
-    xs = list(map(int, sys.argv[1:]))
+_ALGORITHMS = [
+    SortingAlgorithm('quicksort_first', 'Quicksort (first element as pivot)', quicksort_first),
+    SortingAlgorithm('quicksort_second', 'Quicksort (second element as pivot)', quicksort_second),
+    SortingAlgorithm('quicksort_middle', 'Quicksort (middle element as pivot)', quicksort_middle),
+    SortingAlgorithm('quicksort_last', 'Quicksort (last element as pivot)', quicksort_last),
+    SortingAlgorithm('quicksort_random', 'Quicksort (random element as pivot)', quicksort_random),
+]
+
+def _parse_args(args=sys.argv):
+    return list(map(int, args[1:]))
+
+def main(args=sys.argv):
+    xs = _parse_args(args)
     print(quicksort_first(list(xs)))
     print(quicksort_second(list(xs)))
     print(quicksort_middle(list(xs)))
     print(quicksort_last(list(xs)))
     print(quicksort_random(list(xs)))
-else:
-    from algorithms.algorithm import SortingAlgorithm
-    _ALGORITHMS = [
-        SortingAlgorithm('quicksort_first', 'Quicksort (first element as pivot)', quicksort_first),
-        SortingAlgorithm('quicksort_second', 'Quicksort (second element as pivot)', quicksort_second),
-        SortingAlgorithm('quicksort_middle', 'Quicksort (middle element as pivot)', quicksort_middle),
-        SortingAlgorithm('quicksort_last', 'Quicksort (last element as pivot)', quicksort_last),
-        SortingAlgorithm('quicksort_random', 'Quicksort (random element as pivot)', quicksort_random),
-    ]
+
+if __name__ == '__main__':
+    main()
diff --git a/algorithms/impl/selection_sort.py b/algorithms/impl/selection_sort.py
index 27b319f..d5d11d2 100644
--- a/algorithms/impl/selection_sort.py
+++ b/algorithms/impl/selection_sort.py
@@ -2,6 +2,10 @@
 # This file is licensed under the terms of the MIT License.
 # See LICENSE.txt for details.
 
+import sys
+
+from ..algorithm import SortingAlgorithm
+
 def selection_sort(xs):
     for i in range(len(xs) - 1):
         min_i = i
@@ -12,11 +16,16 @@ def selection_sort(xs):
             xs[i], xs[min_i] = xs[min_i], xs[i]
     return xs
 
+_ALGORITHMS = [
+    SortingAlgorithm('selection_sort', 'Selection sort', selection_sort),
+]
+
+def _parse_args(args=sys.argv):
+    return list(map(int, args[1:]))
+
+def main(args=sys.argv):
+    xs = _parse_args(args)
+    print(selection_sort(list(xs)))
+
 if __name__ == '__main__':
-    import sys
-    print(selection_sort(list(map(int, sys.argv[1:]))))
-else:
-    from algorithms.algorithm import SortingAlgorithm
-    _ALGORITHMS = [
-        SortingAlgorithm('selection_sort', 'Selection sort', selection_sort),
-    ]
+    main()
diff --git a/algorithms/inputgen.py b/algorithms/inputgen.py
new file mode 100644
index 0000000..2659ffc
--- /dev/null
+++ b/algorithms/inputgen.py
@@ -0,0 +1,30 @@
+# Copyright 2016 Egor Tensin <Egor.Tensin@gmail.com>
+# This file is licensed under the terms of the MIT License.
+# See LICENSE.txt for details.
+
+from array import array
+from enum import Enum
+from random import seed, sample
+
+seed()
+
+class InputKind(Enum):
+    BEST, AVERAGE, WORST = 'best', 'average', 'worst'
+
+    def __str__(self):
+        return self.value
+
+def _gen_input_from(xs):
+    return array('l', xs)
+
+def gen_input_for_sorting(n, case=InputKind.AVERAGE):
+    if n < 0:
+        raise ValueError('input length must not be a negative number')
+    if case is InputKind.BEST:
+        return _gen_input_from(range(n))
+    elif case is InputKind.AVERAGE:
+        return _gen_input_from(sample(range(n), n))
+    elif case is InputKind.WORST:
+        return _gen_input_from(range(n - 1, -1, -1))
+    else:
+        raise NotImplementedError('invalid input kind: ' + str(case))
diff --git a/algorithms/params.py b/algorithms/params.py
new file mode 100644
index 0000000..a66f7a2
--- /dev/null
+++ b/algorithms/params.py
@@ -0,0 +1,110 @@
+# Copyright 2016 Egor Tensin <Egor.Tensin@gmail.com>
+# This file is licensed under the terms of the MIT License.
+# See LICENSE.txt for details.
+
+from numbers import Integral
+
+from .inputgen import InputKind
+from .plotter import PlotBuilder
+from . import registry
+from .timer import Timer
+
+class AlgorithmParameters:
+    def __init__(self, algorithm, min_len, max_len,
+                 input_kind=InputKind.AVERAGE, iterations=1):
+
+        if isinstance(algorithm, str):
+            algorithm = registry.get(algorithm)
+        self.algorithm = algorithm
+
+        self.input_kind = input_kind
+
+        self._min_len = None
+        self._max_len = None
+        self.min_len = min_len
+        self.max_len = max_len
+
+        self._iterations = None
+        self.iterations = iterations
+
+    @property
+    def min_len(self):
+        return self._min_len
+
+    @min_len.setter
+    def min_len(self, val):
+        if not isinstance(val, Integral):
+            raise TypeError('must be an integral value')
+        val = int(val)
+        if val < 0:
+            raise ValueError('must not be a negative number')
+        if self.max_len is not None and self.max_len < val:
+            raise ValueError('must not be greater than the maximum length')
+        self._min_len = val
+
+    @property
+    def max_len(self):
+        return self._max_len
+
+    @max_len.setter
+    def max_len(self, val):
+        if not isinstance(val, Integral):
+            raise TypeError('must be an integral value')
+        val = int(val)
+        if val < 0:
+            raise ValueError('must not be a negative number')
+        if self.min_len is not None and self.min_len > val:
+            raise ValueError('must not be lesser than the minimum length')
+        self._max_len = val
+
+    @property
+    def iterations(self):
+        return self._iterations
+
+    @iterations.setter
+    def iterations(self, val):
+        if not isinstance(val, Integral):
+            raise TypeError('must be an integral value')
+        val = int(val)
+        if val < 1:
+            raise ValueError('must be a positive number')
+        self._iterations = val
+
+    def measure_running_time(self):
+        input_len_range = list(range(self.min_len, self.max_len + 1))
+        running_time = []
+        for input_len in input_len_range:
+            input_sample = self.algorithm.gen_input(input_len, self.input_kind)
+            input_copies = [list(input_sample) for _ in range(self.iterations)]
+            with Timer(running_time, self.iterations):
+                for i in range(self.iterations):
+                    self.algorithm.function(input_copies[i])
+        return input_len_range, running_time
+
+    @staticmethod
+    def _format_plot_xlabel():
+        return 'Input length'
+
+    @staticmethod
+    def _format_plot_ylabel():
+        return 'Running time (sec)'
+
+    def _format_plot_title(self):
+        return '{}, {} case'.format(
+            self.algorithm.display_name, self.input_kind)
+
+    def _format_plot_suptitle(self):
+        return self.algorithm.display_name
+
+    def plot_running_time(self, output_path=None):
+        plot_builder = PlotBuilder()
+        plot_builder.show_grid()
+        plot_builder.set_xlabel(self._format_plot_xlabel())
+        plot_builder.set_ylabel(self._format_plot_ylabel())
+        plot_builder.set_title(self._format_plot_title())
+        xs, ys = self.measure_running_time()
+        plot_builder.plot(xs, ys)
+        if output_path is None:
+            plot_builder.show()
+        else:
+            plot_builder.save(output_path)
diff --git a/algorithms/plotter.py b/algorithms/plotter.py
new file mode 100644
index 0000000..048894f
--- /dev/null
+++ b/algorithms/plotter.py
@@ -0,0 +1,38 @@
+# Copyright 2016 Egor Tensin <Egor.Tensin@gmail.com>
+# This file is licensed under the terms of the MIT License.
+# See LICENSE.txt for details.
+
+import matplotlib.pyplot as plt
+
+class PlotBuilder:
+    @staticmethod
+    def set_xlabel(s):
+        plt.xlabel(s)
+
+    @staticmethod
+    def set_ylabel(s):
+        plt.ylabel(s)
+
+    @staticmethod
+    def show_grid():
+        plt.grid()
+
+    @staticmethod
+    def set_title(s):
+        plt.title(s)
+
+    @staticmethod
+    def set_suptitle(s):
+        plt.suptitle(s)
+
+    @staticmethod
+    def plot(xs, ys):
+        plt.plot(xs, ys)
+
+    @staticmethod
+    def show():
+        plt.show()
+
+    @staticmethod
+    def save(output_path):
+        plt.savefig(output_path)#, bbox_inches='tight')
diff --git a/algorithms/registry.py b/algorithms/registry.py
index 8f0469d..0f75dce 100644
--- a/algorithms/registry.py
+++ b/algorithms/registry.py
@@ -2,16 +2,12 @@
 # This file is licensed under the terms of the MIT License.
 # See LICENSE.txt for details.
 
-import algorithms.impl
+from . import impl
 
-def refresh_algorithms():
-    algorithms.impl._refresh_algorithms()
+_ALL_ALGORITHMS = impl.refresh_algorithms()
 
 def get_codenames():
-    return algorithms.impl._ALL_ALGORITHMS.keys()
-
-def iter_algorithms():
-    return iter(algorithms.impl._ALL_ALGORITHMS.values())
+    return _ALL_ALGORITHMS.keys()
 
 def get(codename):
-    return algorithms.impl._ALL_ALGORITHMS[codename]
+    return _ALL_ALGORITHMS[codename]
diff --git a/algorithms/timer.py b/algorithms/timer.py
new file mode 100644
index 0000000..d334b94
--- /dev/null
+++ b/algorithms/timer.py
@@ -0,0 +1,23 @@
+# Copyright 2016 Egor Tensin <Egor.Tensin@gmail.com>
+# This file is licensed under the terms of the MIT License.
+# See LICENSE.txt for details.
+
+import gc, time
+
+def get_timestamp():
+    return time.perf_counter()
+
+class Timer:
+    def __init__(self, dest, iterations=1):
+        self._dest = dest
+        self._iterations = iterations
+
+    def __enter__(self):
+        gc.disable()
+        self._start = get_timestamp()
+        return self
+
+    def __exit__(self, *args):
+        end = get_timestamp()
+        gc.enable()
+        self._dest.append((end - self._start) / self._iterations)