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Constants ¶
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Variables ¶
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Functions ¶
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Types ¶
type FloatSlidingWindow ¶
type FloatSlidingWindow interface {
// Add a value to the end of the queue. On overflow returns true and the
// oldest value, which is also removed from the buffer. Otherwise
// returns (false, _).
Push(value float64) (bool, float64)
// Returns the elements in the buffer, ordered by time of insertion
// (oldest first).
Contents() []float64
// Returns a pointer to the most recently added element. The pointer can
// be used to modify the last element. It is only valid until the next
// call to Push(). Return nil if called on an empty buffer.
Head() *float64
}
FloatSlidingWindow is a buffer with a fixed capacity. Elements are inserted/removed in the FIFO order. Elements are removed from the buffer only when it runs out of capacity and a new element is inserted.
func NewFloatSlidingWindow ¶
func NewFloatSlidingWindow(size int) FloatSlidingWindow
NewFloatSlidingWindow returns a new instance of FloatSlidingWindowImpl with a given size.
type Histogram ¶
type Histogram interface {
// Returns an approximation of the given percentile of the distribution.
// Note: the argument passed to Percentile() is a number between
// 0 and 1. For example 0.5 corresponds to the median and 0.9 to the
// 90th percentile.
// If the histogram is empty, Percentile() returns 0.0.
Percentile(percentile float64) float64
// Add a sample with a given value and weight.
AddSample(value float64, weight float64)
// Remove a sample with a given value and weight. Note that the total
// weight of samples with a given value cannot be negative.
SubtractSample(value float64, weight float64)
// Returns true if the histogram is empty.
IsEmpty() bool
}
Histogram represents an approximate distribution of some variable.
func NewHistogram ¶
func NewHistogram(options HistogramOptions) Histogram
NewHistogram returns a new Histogram instance using given options.
type HistogramOptions ¶
type HistogramOptions interface {
// Returns the number of buckets in the histogram.
NumBuckets() int
// Returns the index of the bucket to which the given value falls.
// If the value is outside of the range covered by the histogram, it
// returns the closest bucket (either the first or the last one).
FindBucket(value float64) int
// Returns the start of the bucket with a given index. If the index is
// outside the [0..NumBuckets() - 1] range, the result is undefined.
GetBucketStart(bucket int) float64
// Returns the minimum weight for a bucket to be considered non-empty.
Epsilon() float64
}
HistogramOptions define the number and size of buckets of a histogram.
func NewExponentialHistogramOptions ¶
func NewExponentialHistogramOptions( maxValue float64, firstBucketSize float64, ratio float64, epsilon float64) (HistogramOptions, error)
NewExponentialHistogramOptions returns HistogramOptions describing a histogram with exponentially growing bucket boundaries. The first bucket covers the range [0..firstBucketSize). Consecutive buckets are of the form [x(n)..x(n) * ratio) for n = 1 .. numBuckets - 1. The last bucket start is larger or equal to maxValue. Requires maxValue > 0, firstBucketSize > 0, ratio > 1, epsilon > 0.
func NewLinearHistogramOptions ¶
func NewLinearHistogramOptions( maxValue float64, bucketSize float64, epsilon float64) (HistogramOptions, error)
NewLinearHistogramOptions returns HistogramOptions describing a histogram with a given number of fixed-size buckets, with the first bucket start at 0.0 and the last bucket start larger or equal to maxValue. Requires maxValue > 0, bucketSize > 0, epsilon > 0.
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