README
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ndn-dpdk/core/runningstat
This package implements Knuth and Welford's method for computing the standard deviation.
Compared to the original RunningStats C++ class, this implementation does not support skewness and kurtosis, adds tracking of the minimum and maximum values, and can be configured to periodically sample the input instead of sampling every input.
To add an input, use the C function RunningStat_Push, or RunningStat_Push1 when minimum and maximum are unnecessary.
To compute the average and standard deviation, use the Go type RunningStat.
Documentation
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Overview ¶
Package runningstat implements Knuth and Welford's method for computing the standard deviation.
Index ¶
Constants ¶
This section is empty.
Variables ¶
var GqlSnapshotType = graphql.NewObject(graphql.ObjectConfig{ Name: "RunningStatSnapshot", Fields: gqlserver.BindFields[Snapshot](nil), })
GqlSnapshotType is the GraphQL type for Snapshot.
Functions ¶
This section is empty.
Types ¶
type IntStat ¶
type IntStat C.RunningStatI
func IntFromPtr ¶
IntFromPtr converts *C.RunningStatI to IntStat.
type RunningStat ¶
type RunningStat C.RunningStat
RunningStat collects statistics and allows computing mean and variance. Algorithm comes from https://www.johndcook.com/blog/standard_deviation/ .
func FromPtr ¶
func FromPtr(ptr unsafe.Pointer) (s *RunningStat)
FromPtr converts *C.RunningStat to RunningStat.
func (*RunningStat) Init ¶
func (s *RunningStat) Init(sampleInterval int)
Init initializes the instance and clears existing data. sampleInterval: how often to collect sample, will be adjusted to nearest power of two and truncated between 1 and 2^30.
func (*RunningStat) Read ¶
func (s *RunningStat) Read() Snapshot
Read returns current counters as Snapshot.
type Snapshot ¶
type Snapshot struct {
Count uint64 `json:"count" gqldesc:"Number of input values."`
Len uint64 `json:"len" gqldesc:"Number of collected samples."`
Mean float64 `json:"mean" gqldesc:"Mean value. Valid if count>0."`
Variance float64 `json:"variance" gqldesc:"Variance of samples. Valid if count>1."`
Stdev float64 `json:"stdev" gqldesc:"Standard deviation of samples. Valid if count>1."`
M1 float64 `json:"m1"`
M2 float64 `json:"m2"`
Min *uint64 `json:"min" gqldesc:"Minimum value. Valid if count>0."`
Max *uint64 `json:"max" gqldesc:"Maximum value. Valid if count>0."`
}
Snapshot contains a snapshot of RunningStat reading.
Source Files