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This commit is contained in:
Seth Hall 2013-03-13 22:55:03 -04:00
parent 09cbaa7ccc
commit 8778761c07
30 changed files with 833 additions and 848 deletions
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65
scripts/base/frameworks/measurement/plugins/variance.bro Normal file
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@load ./average
module Metrics;
export {
redef enum Calculation += {
## Find the variance of the values.
VARIANCE
};
redef record ResultVal += {
## For numeric data, this calculates the variance.
variance: double &log &optional;
};
}
redef record ResultVal += {
# Internal use only. Used for incrementally calculating variance.
prev_avg: double &optional;
# Internal use only. For calculating incremental variance.
var_s: double &optional;
};
hook add_to_calculation(filter: Filter, val: double, data: DataPoint, result: ResultVal) &priority=5
{
if ( VARIANCE in filter$measure )
result$prev_avg = result$average;
}
# Reduced priority since this depends on the average
hook add_to_calculation(filter: Filter, val: double, data: DataPoint, result: ResultVal) &priority=-5
{
if ( VARIANCE in filter$measure )
{
if ( ! result?$var_s )
result$var_s = 0.0;
result$var_s += (val - result$prev_avg) * (val - result$average);
result$variance = (val > 0) ? result$var_s/val : 0.0;
}
}
# Reduced priority since this depends on the average
hook plugin_merge_measurements(result: ResultVal, rv1: ResultVal, rv2: ResultVal) &priority=-5
{
if ( rv1?$var_s && rv2?$var_s )
{
local rv1_avg_sq = (rv1$average - result$average);
rv1_avg_sq = rv1_avg_sq*rv1_avg_sq;
local rv2_avg_sq = (rv2$average - result$average);
rv2_avg_sq = rv2_avg_sq*rv2_avg_sq;
result$var_s = rv1$num*(rv1$var_s/rv1$num + rv1_avg_sq) + rv2$num*(rv2$var_s/rv2$num + rv2_avg_sq);
}
else if ( rv1?$var_s )
result$var_s = rv1$var_s;
else if ( rv2?$var_s )
result$var_s = rv2$var_s;
if ( rv1?$prev_avg && rv2?$prev_avg )
result$prev_avg = ((rv1$prev_avg*rv1$num) + (rv2$prev_avg*rv2$num))/(rv1$num+rv2$num);
else if ( rv1?$prev_avg )
result$prev_avg = rv1$prev_avg;
else if ( rv2?$prev_avg )
result$prev_avg = rv2$prev_avg;
}