95 lines
2.7 KiB
Go
95 lines
2.7 KiB
Go
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package netmap
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import (
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"errors"
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"github.com/nspcc-dev/hrw"
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)
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// Context contains references to named filters and cached numeric values.
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type Context struct {
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// Netmap is a netmap structure to operate on.
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Netmap *Netmap
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// Filters stores processed filters.
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Filters map[string]*Filter
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// Selectors stores processed selectors.
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Selectors map[string]*Selector
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// Selections stores result of selector processing.
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Selections map[string][]Nodes
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// numCache stores parsed numeric values.
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numCache map[*Filter]uint64
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// pivot is a seed for HRW.
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pivot []byte
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// pivotHash is a saved HRW hash of pivot
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pivotHash uint64
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// aggregator is returns aggregator determining bucket weight.
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// By default it returns mean value from IQR interval.
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aggregator func() aggregator
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// weightFunc is a weighting function for determining node priority.
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// By default in combines favours low price and high capacity.
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weightFunc weightFunc
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// container backup factor is a factor for selector counters that expand
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// amount of chosen nodes.
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cbf uint32
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}
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// Various validation errors.
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var (
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ErrMissingField = errors.New("netmap: nil field")
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ErrInvalidFilterName = errors.New("netmap: filter name is invalid")
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ErrInvalidNumber = errors.New("netmap: number value expected")
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ErrInvalidFilterOp = errors.New("netmap: invalid filter operation")
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ErrFilterNotFound = errors.New("netmap: filter not found")
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ErrNonEmptyFilters = errors.New("netmap: simple filter must no contain sub-filters")
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ErrNotEnoughNodes = errors.New("netmap: not enough nodes to SELECT from")
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ErrSelectorNotFound = errors.New("netmap: selector not found")
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ErrUnnamedTopFilter = errors.New("netmap: all filters on top level must be named")
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)
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// NewContext creates new context. It contains various caches.
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// In future it may create hierarchical netmap structure to work with.
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func NewContext(nm *Netmap) *Context {
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return &Context{
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Netmap: nm,
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Filters: make(map[string]*Filter),
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Selectors: make(map[string]*Selector),
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Selections: make(map[string][]Nodes),
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numCache: make(map[*Filter]uint64),
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aggregator: newMeanIQRAgg,
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weightFunc: GetDefaultWeightFunc(nm.Nodes),
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cbf: defaultCBF,
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}
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}
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func (c *Context) setPivot(pivot []byte) {
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if len(pivot) != 0 {
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c.pivot = pivot
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c.pivotHash = hrw.Hash(pivot)
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}
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}
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func (c *Context) setCBF(cbf uint32) {
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if cbf == 0 {
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c.cbf = defaultCBF
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} else {
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c.cbf = cbf
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}
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}
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// GetDefaultWeightFunc returns default weighting function.
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func GetDefaultWeightFunc(ns Nodes) weightFunc {
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mean := newMeanAgg()
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min := newMinAgg()
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for i := range ns {
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mean.Add(float64(ns[i].Capacity))
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min.Add(float64(ns[i].Price))
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}
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return newWeightFunc(
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newSigmoidNorm(mean.Compute()),
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newReverseMinNorm(min.Compute()))
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}
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