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// Copyright 2016 Google Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
syntax = "proto3";
package google.api;
import "google/api/annotations.proto";
import "google/protobuf/any.proto";
import "google/protobuf/timestamp.proto";
option go_package = "google.golang.org/genproto/googleapis/api/distribution;distribution";
option java_multiple_files = true;
option java_outer_classname = "DistributionProto";
option java_package = "com.google.api";
// Distribution contains summary statistics for a population of values and,
// optionally, a histogram representing the distribution of those values across
// a specified set of histogram buckets.
//
// The summary statistics are the count, mean, sum of the squared deviation from
// the mean, the minimum, and the maximum of the set of population of values.
//
// The histogram is based on a sequence of buckets and gives a count of values
// that fall into each bucket. The boundaries of the buckets are given either
// explicitly or by specifying parameters for a method of computing them
// (buckets of fixed width or buckets of exponentially increasing width).
//
// Although it is not forbidden, it is generally a bad idea to include
// non-finite values (infinities or NaNs) in the population of values, as this
// will render the `mean` and `sum_of_squared_deviation` fields meaningless.
message Distribution {
// The range of the population values.
message Range {
// The minimum of the population values.
double min = 1;
// The maximum of the population values.
double max = 2;
}
// A Distribution may optionally contain a histogram of the values in the
// population. The histogram is given in `bucket_counts` as counts of values
// that fall into one of a sequence of non-overlapping buckets. The sequence
// of buckets is described by `bucket_options`.
//
// A bucket specifies an inclusive lower bound and exclusive upper bound for
// the values that are counted for that bucket. The upper bound of a bucket
// is strictly greater than the lower bound.
//
// The sequence of N buckets for a Distribution consists of an underflow
// bucket (number 0), zero or more finite buckets (number 1 through N - 2) and
// an overflow bucket (number N - 1). The buckets are contiguous: the lower
// bound of bucket i (i > 0) is the same as the upper bound of bucket i - 1.
// The buckets span the whole range of finite values: lower bound of the
// underflow bucket is -infinity and the upper bound of the overflow bucket is
// +infinity. The finite buckets are so-called because both bounds are
// finite.
//
// `BucketOptions` describes bucket boundaries in one of three ways. Two
// describe the boundaries by giving parameters for a formula to generate
// boundaries and one gives the bucket boundaries explicitly.
//
// If `bucket_boundaries` is not given, then no `bucket_counts` may be given.
message BucketOptions {
// Specify a sequence of buckets that all have the same width (except
// overflow and underflow). Each bucket represents a constant absolute
// uncertainty on the specific value in the bucket.
//
// Defines `num_finite_buckets + 2` (= N) buckets with these boundaries for
// bucket `i`:
//
// Upper bound (0 <= i < N-1): offset + (width * i).
// Lower bound (1 <= i < N): offset + (width * (i - 1)).
message Linear {
// Must be greater than 0.
int32 num_finite_buckets = 1;
// Must be greater than 0.
double width = 2;
// Lower bound of the first bucket.
double offset = 3;
}
// Specify a sequence of buckets that have a width that is proportional to
// the value of the lower bound. Each bucket represents a constant relative
// uncertainty on a specific value in the bucket.
//
// Defines `num_finite_buckets + 2` (= N) buckets with these boundaries for
// bucket i:
//
// Upper bound (0 <= i < N-1): scale * (growth_factor ^ i).
// Lower bound (1 <= i < N): scale * (growth_factor ^ (i - 1)).
message Exponential {
// Must be greater than 0.
int32 num_finite_buckets = 1;
// Must be greater than 1.
double growth_factor = 2;
// Must be greater than 0.
double scale = 3;
}
// A set of buckets with arbitrary widths.
//
// Defines `size(bounds) + 1` (= N) buckets with these boundaries for
// bucket i:
//
// Upper bound (0 <= i < N-1): bounds[i]
// Lower bound (1 <= i < N); bounds[i - 1]
//
// There must be at least one element in `bounds`. If `bounds` has only one
// element, there are no finite buckets, and that single element is the
// common boundary of the overflow and underflow buckets.
message Explicit {
// The values must be monotonically increasing.
repeated double bounds = 1;
}
// Exactly one of these three fields must be set.
oneof options {
// The linear bucket.
Linear linear_buckets = 1;
// The exponential buckets.
Exponential exponential_buckets = 2;
// The explicit buckets.
Explicit explicit_buckets = 3;
}
}
// The number of values in the population. Must be non-negative.
int64 count = 1;
// The arithmetic mean of the values in the population. If `count` is zero
// then this field must be zero.
double mean = 2;
// The sum of squared deviations from the mean of the values in the
// population. For values x_i this is:
//
// Sum[i=1..n]((x_i - mean)^2)
//
// Knuth, "The Art of Computer Programming", Vol. 2, page 323, 3rd edition
// describes Welford's method for accumulating this sum in one pass.
//
// If `count` is zero then this field must be zero.
double sum_of_squared_deviation = 3;
// If specified, contains the range of the population values. The field
// must not be present if the `count` is zero.
Range range = 4;
// Defines the histogram bucket boundaries.
BucketOptions bucket_options = 6;
// If `bucket_options` is given, then the sum of the values in `bucket_counts`
// must equal the value in `count`. If `bucket_options` is not given, no
// `bucket_counts` fields may be given.
//
// Bucket counts are given in order under the numbering scheme described
// above (the underflow bucket has number 0; the finite buckets, if any,
// have numbers 1 through N-2; the overflow bucket has number N-1).
//
// The size of `bucket_counts` must be no greater than N as defined in
// `bucket_options`.
//
// Any suffix of trailing zero bucket_count fields may be omitted.
repeated int64 bucket_counts = 7;
}