forked from TrueCloudLab/frostfs-node
91 lines
2.5 KiB
Go
91 lines
2.5 KiB
Go
package eigentrustcalc
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import (
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"fmt"
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"github.com/nspcc-dev/neofs-node/pkg/services/reputation"
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"github.com/nspcc-dev/neofs-node/pkg/util"
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)
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// Prm groups the required parameters of the Calculator's constructor.
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//
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// All values must comply with the requirements imposed on them.
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// Passing incorrect parameter values will result in constructor
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// failure (error or panic depending on the implementation).
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type Prm struct {
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// Alpha parameter from origin EigenTrust algorithm
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// http://ilpubs.stanford.edu:8090/562/1/2002-56.pdf Ch.5.1.
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//
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// Must be in range (0, 1).
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Alpha float64
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// Source of initial node trust values
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//
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// Must not be nil.
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InitialTrustSource InitialTrustSource
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DaughterTrustSource DaughterTrustIteratorProvider
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IntermediateValueTarget IntermediateWriterProvider
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FinalResultTarget IntermediateWriterProvider
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WorkerPool util.WorkerPool
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}
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// Calculator is a processor of a single iteration of EigenTrust algorithm.
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//
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// For correct operation, the Calculator must be created
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// using the constructor (New) based on the required parameters
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// and optional components. After successful creation,
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// the Calculator is immediately ready to work through
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// API of external control of calculations and data transfer.
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type Calculator struct {
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alpha, beta reputation.TrustValue // beta = 1 - alpha
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prm Prm
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opts *options
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}
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const invalidPrmValFmt = "invalid parameter %s (%T):%v"
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func panicOnPrmValue(n string, v interface{}) {
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panic(fmt.Sprintf(invalidPrmValFmt, n, v, v))
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}
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// New creates a new instance of the Calculator.
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//
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// Panics if at least one value of the parameters is invalid.
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//
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// The created Calculator does not require additional
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// initialization and is completely ready for work.
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func New(prm Prm, opts ...Option) *Calculator {
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switch {
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case prm.Alpha <= 0 || prm.Alpha >= 1:
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panicOnPrmValue("Alpha", prm.Alpha)
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case prm.InitialTrustSource == nil:
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panicOnPrmValue("InitialTrustSource", prm.InitialTrustSource)
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case prm.DaughterTrustSource == nil:
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panicOnPrmValue("DaughterTrustSource", prm.DaughterTrustSource)
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case prm.IntermediateValueTarget == nil:
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panicOnPrmValue("IntermediateValueTarget", prm.IntermediateValueTarget)
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case prm.FinalResultTarget == nil:
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panicOnPrmValue("FinalResultTarget", prm.FinalResultTarget)
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case prm.WorkerPool == nil:
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panicOnPrmValue("WorkerPool", prm.WorkerPool)
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}
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o := defaultOpts()
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for _, opt := range opts {
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opt(o)
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}
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return &Calculator{
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alpha: reputation.TrustValueFromFloat64(prm.Alpha),
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beta: reputation.TrustValueFromFloat64(1 - prm.Alpha),
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prm: prm,
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opts: o,
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}
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}
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