41 lines
1.5 KiB
Go
41 lines
1.5 KiB
Go
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package hostpool
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// --- Value Calculators -----------------
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import (
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"math"
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)
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// --- Definitions -----------------------
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// Structs implementing this interface are used to convert the average response time for a host
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// into a score that can be used to weight hosts in the epsilon greedy hostpool. Lower response
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// times should yield higher scores (we want to select the faster hosts more often) The default
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// LinearEpsilonValueCalculator just uses the reciprocal of the response time. In practice, any
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// decreasing function from the positive reals to the positive reals should work.
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type EpsilonValueCalculator interface {
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CalcValueFromAvgResponseTime(float64) float64
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}
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type LinearEpsilonValueCalculator struct{}
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type LogEpsilonValueCalculator struct{ LinearEpsilonValueCalculator }
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type PolynomialEpsilonValueCalculator struct {
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LinearEpsilonValueCalculator
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Exp float64 // the exponent to which we will raise the value to reweight
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}
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// -------- Methods -----------------------
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func (c *LinearEpsilonValueCalculator) CalcValueFromAvgResponseTime(v float64) float64 {
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return 1.0 / v
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}
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func (c *LogEpsilonValueCalculator) CalcValueFromAvgResponseTime(v float64) float64 {
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// we need to add 1 to v so that this will be defined on all positive floats
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return c.LinearEpsilonValueCalculator.CalcValueFromAvgResponseTime(math.Log(v + 1.0))
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}
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func (c *PolynomialEpsilonValueCalculator) CalcValueFromAvgResponseTime(v float64) float64 {
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return c.LinearEpsilonValueCalculator.CalcValueFromAvgResponseTime(math.Pow(v, c.Exp))
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}
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