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1'''
2Created on May 19, 2011
3
4@author: bungeman
5'''
6
7import re
8import math
9
10class BenchDataPoint:
11    """A single data point produced by bench.
12
13    (str, str, str, float, {str:str})"""
14    def __init__(self, bench, config, time_type, time, settings):
15        self.bench = bench
16        self.config = config
17        self.time_type = time_type
18        self.time = time
19        self.settings = settings
20
21    def __repr__(self):
22        return "BenchDataPoint(%s, %s, %s, %s, %s)" % (
23                   str(self.bench),
24                   str(self.config),
25                   str(self.time_type),
26                   str(self.time),
27                   str(self.settings),
28               )
29
30class _ExtremeType(object):
31    """Instances of this class compare greater or less than other objects."""
32    def __init__(self, cmpr, rep):
33        object.__init__(self)
34        self._cmpr = cmpr
35        self._rep = rep
36
37    def __cmp__(self, other):
38        if isinstance(other, self.__class__) and other._cmpr == self._cmpr:
39            return 0
40        return self._cmpr
41
42    def __repr__(self):
43        return self._rep
44
45Max = _ExtremeType(1, "Max")
46Min = _ExtremeType(-1, "Min")
47
48def parse(settings, lines):
49    """Parses bench output into a useful data structure.
50
51    ({str:str}, __iter__ -> str) -> [BenchDataPoint]"""
52
53    benches = []
54    current_bench = None
55    setting_re = '([^\s=]+)(?:=(\S+))?'
56    settings_re = 'skia bench:((?:\s+' + setting_re + ')*)'
57    bench_re = 'running bench (?:\[\d+ \d+\] )?\s*(\S+)'
58    time_re = '(?:(\w*)msecs = )?\s*(\d+\.\d+)'
59    config_re = '(\S+): ((?:' + time_re + '\s+)+)'
60
61    for line in lines:
62
63        #see if this line is a settings line
64        settingsMatch = re.search(settings_re, line)
65        if (settingsMatch):
66            settings = dict(settings)
67            for settingMatch in re.finditer(setting_re, settingsMatch.group(1)):
68                if (settingMatch.group(2)):
69                    settings[settingMatch.group(1)] = settingMatch.group(2)
70                else:
71                    settings[settingMatch.group(1)] = True
72
73        #see if this line starts a new bench
74        new_bench = re.search(bench_re, line)
75        if new_bench:
76            current_bench = new_bench.group(1)
77
78        #add configs on this line to the current bench
79        if current_bench:
80            for new_config in re.finditer(config_re, line):
81                current_config = new_config.group(1)
82                times = new_config.group(2)
83                for new_time in re.finditer(time_re, times):
84                    current_time_type = new_time.group(1)
85                    current_time = float(new_time.group(2))
86                    benches.append(BenchDataPoint(
87                            current_bench
88                            , current_config
89                            , current_time_type
90                            , current_time
91                            , settings))
92
93    return benches
94
95class LinearRegression:
96    """Linear regression data based on a set of data points.
97
98    ([(Number,Number)])
99    There must be at least two points for this to make sense."""
100    def __init__(self, points):
101        n = len(points)
102        max_x = Min
103        min_x = Max
104
105        Sx = 0.0
106        Sy = 0.0
107        Sxx = 0.0
108        Sxy = 0.0
109        Syy = 0.0
110        for point in points:
111            x = point[0]
112            y = point[1]
113            max_x = max(max_x, x)
114            min_x = min(min_x, x)
115
116            Sx += x
117            Sy += y
118            Sxx += x*x
119            Sxy += x*y
120            Syy += y*y
121
122        B = (n*Sxy - Sx*Sy) / (n*Sxx - Sx*Sx)
123        a = (1.0/n)*(Sy - B*Sx)
124
125        se2 = 0
126        sB2 = 0
127        sa2 = 0
128        if (n >= 3):
129            se2 = (1.0/(n*(n-2)) * (n*Syy - Sy*Sy - B*B*(n*Sxx - Sx*Sx)))
130            sB2 = (n*se2) / (n*Sxx - Sx*Sx)
131            sa2 = sB2 * (1.0/n) * Sxx
132
133
134        self.slope = B
135        self.intercept = a
136        self.serror = math.sqrt(max(0, se2))
137        self.serror_slope = math.sqrt(max(0, sB2))
138        self.serror_intercept = math.sqrt(max(0, sa2))
139        self.max_x = max_x
140        self.min_x = min_x
141
142    def __repr__(self):
143        return "LinearRegression(%s, %s, %s, %s, %s)" % (
144                   str(self.slope),
145                   str(self.intercept),
146                   str(self.serror),
147                   str(self.serror_slope),
148                   str(self.serror_intercept),
149               )
150
151    def find_min_slope(self):
152        """Finds the minimal slope given one standard deviation."""
153        slope = self.slope
154        intercept = self.intercept
155        error = self.serror
156        regr_start = self.min_x
157        regr_end = self.max_x
158        regr_width = regr_end - regr_start
159
160        if slope < 0:
161            lower_left_y = slope*regr_start + intercept - error
162            upper_right_y = slope*regr_end + intercept + error
163            return min(0, (upper_right_y - lower_left_y) / regr_width)
164
165        elif slope > 0:
166            upper_left_y = slope*regr_start + intercept + error
167            lower_right_y = slope*regr_end + intercept - error
168            return max(0, (lower_right_y - upper_left_y) / regr_width)
169
170        return 0
171
172def CreateRevisionLink(revision_number):
173    """Returns HTML displaying the given revision number and linking to
174    that revision's change page at code.google.com, e.g.
175    http://code.google.com/p/skia/source/detail?r=2056
176    """
177    return '<a href="http://code.google.com/p/skia/source/detail?r=%s">%s</a>'%(
178        revision_number, revision_number)
179