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diff --git a/vendor/github.com/golang/geo/s1/interval.go b/vendor/github.com/golang/geo/s1/interval.go
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--- a/vendor/github.com/golang/geo/s1/interval.go
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-// Copyright 2014 Google Inc. All rights reserved.
-//
-// 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.
-
-package s1
-
-import (
- "math"
- "strconv"
-)
-
-// An Interval represents a closed interval on a unit circle (also known
-// as a 1-dimensional sphere). It is capable of representing the empty
-// interval (containing no points), the full interval (containing all
-// points), and zero-length intervals (containing a single point).
-//
-// Points are represented by the angle they make with the positive x-axis in
-// the range [-π, π]. An interval is represented by its lower and upper
-// bounds (both inclusive, since the interval is closed). The lower bound may
-// be greater than the upper bound, in which case the interval is "inverted"
-// (i.e. it passes through the point (-1, 0)).
-//
-// The point (-1, 0) has two valid representations, π and -π. The
-// normalized representation of this point is π, so that endpoints
-// of normal intervals are in the range (-π, π]. We normalize the latter to
-// the former in IntervalFromEndpoints. However, we take advantage of the point
-// -π to construct two special intervals:
-// The full interval is [-π, π]
-// The empty interval is [π, -π].
-//
-// Treat the exported fields as read-only.
-type Interval struct {
- Lo, Hi float64
-}
-
-// IntervalFromEndpoints constructs a new interval from endpoints.
-// Both arguments must be in the range [-π,π]. This function allows inverted intervals
-// to be created.
-func IntervalFromEndpoints(lo, hi float64) Interval {
- i := Interval{lo, hi}
- if lo == -math.Pi && hi != math.Pi {
- i.Lo = math.Pi
- }
- if hi == -math.Pi && lo != math.Pi {
- i.Hi = math.Pi
- }
- return i
-}
-
-// IntervalFromPointPair returns the minimal interval containing the two given points.
-// Both arguments must be in [-π,π].
-func IntervalFromPointPair(a, b float64) Interval {
- if a == -math.Pi {
- a = math.Pi
- }
- if b == -math.Pi {
- b = math.Pi
- }
- if positiveDistance(a, b) <= math.Pi {
- return Interval{a, b}
- }
- return Interval{b, a}
-}
-
-// EmptyInterval returns an empty interval.
-func EmptyInterval() Interval { return Interval{math.Pi, -math.Pi} }
-
-// FullInterval returns a full interval.
-func FullInterval() Interval { return Interval{-math.Pi, math.Pi} }
-
-// IsValid reports whether the interval is valid.
-func (i Interval) IsValid() bool {
- return (math.Abs(i.Lo) <= math.Pi && math.Abs(i.Hi) <= math.Pi &&
- !(i.Lo == -math.Pi && i.Hi != math.Pi) &&
- !(i.Hi == -math.Pi && i.Lo != math.Pi))
-}
-
-// IsFull reports whether the interval is full.
-func (i Interval) IsFull() bool { return i.Lo == -math.Pi && i.Hi == math.Pi }
-
-// IsEmpty reports whether the interval is empty.
-func (i Interval) IsEmpty() bool { return i.Lo == math.Pi && i.Hi == -math.Pi }
-
-// IsInverted reports whether the interval is inverted; that is, whether Lo > Hi.
-func (i Interval) IsInverted() bool { return i.Lo > i.Hi }
-
-// Invert returns the interval with endpoints swapped.
-func (i Interval) Invert() Interval {
- return Interval{i.Hi, i.Lo}
-}
-
-// Center returns the midpoint of the interval.
-// It is undefined for full and empty intervals.
-func (i Interval) Center() float64 {
- c := 0.5 * (i.Lo + i.Hi)
- if !i.IsInverted() {
- return c
- }
- if c <= 0 {
- return c + math.Pi
- }
- return c - math.Pi
-}
-
-// Length returns the length of the interval.
-// The length of an empty interval is negative.
-func (i Interval) Length() float64 {
- l := i.Hi - i.Lo
- if l >= 0 {
- return l
- }
- l += 2 * math.Pi
- if l > 0 {
- return l
- }
- return -1
-}
-
-// Assumes p ∈ (-π,π].
-func (i Interval) fastContains(p float64) bool {
- if i.IsInverted() {
- return (p >= i.Lo || p <= i.Hi) && !i.IsEmpty()
- }
- return p >= i.Lo && p <= i.Hi
-}
-
-// Contains returns true iff the interval contains p.
-// Assumes p ∈ [-π,π].
-func (i Interval) Contains(p float64) bool {
- if p == -math.Pi {
- p = math.Pi
- }
- return i.fastContains(p)
-}
-
-// ContainsInterval returns true iff the interval contains oi.
-func (i Interval) ContainsInterval(oi Interval) bool {
- if i.IsInverted() {
- if oi.IsInverted() {
- return oi.Lo >= i.Lo && oi.Hi <= i.Hi
- }
- return (oi.Lo >= i.Lo || oi.Hi <= i.Hi) && !i.IsEmpty()
- }
- if oi.IsInverted() {
- return i.IsFull() || oi.IsEmpty()
- }
- return oi.Lo >= i.Lo && oi.Hi <= i.Hi
-}
-
-// InteriorContains returns true iff the interior of the interval contains p.
-// Assumes p ∈ [-π,π].
-func (i Interval) InteriorContains(p float64) bool {
- if p == -math.Pi {
- p = math.Pi
- }
- if i.IsInverted() {
- return p > i.Lo || p < i.Hi
- }
- return (p > i.Lo && p < i.Hi) || i.IsFull()
-}
-
-// InteriorContainsInterval returns true iff the interior of the interval contains oi.
-func (i Interval) InteriorContainsInterval(oi Interval) bool {
- if i.IsInverted() {
- if oi.IsInverted() {
- return (oi.Lo > i.Lo && oi.Hi < i.Hi) || oi.IsEmpty()
- }
- return oi.Lo > i.Lo || oi.Hi < i.Hi
- }
- if oi.IsInverted() {
- return i.IsFull() || oi.IsEmpty()
- }
- return (oi.Lo > i.Lo && oi.Hi < i.Hi) || i.IsFull()
-}
-
-// Intersects returns true iff the interval contains any points in common with oi.
-func (i Interval) Intersects(oi Interval) bool {
- if i.IsEmpty() || oi.IsEmpty() {
- return false
- }
- if i.IsInverted() {
- return oi.IsInverted() || oi.Lo <= i.Hi || oi.Hi >= i.Lo
- }
- if oi.IsInverted() {
- return oi.Lo <= i.Hi || oi.Hi >= i.Lo
- }
- return oi.Lo <= i.Hi && oi.Hi >= i.Lo
-}
-
-// InteriorIntersects returns true iff the interior of the interval contains any points in common with oi, including the latter's boundary.
-func (i Interval) InteriorIntersects(oi Interval) bool {
- if i.IsEmpty() || oi.IsEmpty() || i.Lo == i.Hi {
- return false
- }
- if i.IsInverted() {
- return oi.IsInverted() || oi.Lo < i.Hi || oi.Hi > i.Lo
- }
- if oi.IsInverted() {
- return oi.Lo < i.Hi || oi.Hi > i.Lo
- }
- return (oi.Lo < i.Hi && oi.Hi > i.Lo) || i.IsFull()
-}
-
-// Compute distance from a to b in [0,2π], in a numerically stable way.
-func positiveDistance(a, b float64) float64 {
- d := b - a
- if d >= 0 {
- return d
- }
- return (b + math.Pi) - (a - math.Pi)
-}
-
-// Union returns the smallest interval that contains both the interval and oi.
-func (i Interval) Union(oi Interval) Interval {
- if oi.IsEmpty() {
- return i
- }
- if i.fastContains(oi.Lo) {
- if i.fastContains(oi.Hi) {
- // Either oi ⊂ i, or i ∪ oi is the full interval.
- if i.ContainsInterval(oi) {
- return i
- }
- return FullInterval()
- }
- return Interval{i.Lo, oi.Hi}
- }
- if i.fastContains(oi.Hi) {
- return Interval{oi.Lo, i.Hi}
- }
-
- // Neither endpoint of oi is in i. Either i ⊂ oi, or i and oi are disjoint.
- if i.IsEmpty() || oi.fastContains(i.Lo) {
- return oi
- }
-
- // This is the only hard case where we need to find the closest pair of endpoints.
- if positiveDistance(oi.Hi, i.Lo) < positiveDistance(i.Hi, oi.Lo) {
- return Interval{oi.Lo, i.Hi}
- }
- return Interval{i.Lo, oi.Hi}
-}
-
-// Intersection returns the smallest interval that contains the intersection of the interval and oi.
-func (i Interval) Intersection(oi Interval) Interval {
- if oi.IsEmpty() {
- return EmptyInterval()
- }
- if i.fastContains(oi.Lo) {
- if i.fastContains(oi.Hi) {
- // Either oi ⊂ i, or i and oi intersect twice. Neither are empty.
- // In the first case we want to return i (which is shorter than oi).
- // In the second case one of them is inverted, and the smallest interval
- // that covers the two disjoint pieces is the shorter of i and oi.
- // We thus want to pick the shorter of i and oi in both cases.
- if oi.Length() < i.Length() {
- return oi
- }
- return i
- }
- return Interval{oi.Lo, i.Hi}
- }
- if i.fastContains(oi.Hi) {
- return Interval{i.Lo, oi.Hi}
- }
-
- // Neither endpoint of oi is in i. Either i ⊂ oi, or i and oi are disjoint.
- if oi.fastContains(i.Lo) {
- return i
- }
- return EmptyInterval()
-}
-
-// AddPoint returns the interval expanded by the minimum amount necessary such
-// that it contains the given point "p" (an angle in the range [-π, π]).
-func (i Interval) AddPoint(p float64) Interval {
- if math.Abs(p) > math.Pi {
- return i
- }
- if p == -math.Pi {
- p = math.Pi
- }
- if i.fastContains(p) {
- return i
- }
- if i.IsEmpty() {
- return Interval{p, p}
- }
- if positiveDistance(p, i.Lo) < positiveDistance(i.Hi, p) {
- return Interval{p, i.Hi}
- }
- return Interval{i.Lo, p}
-}
-
-// Define the maximum rounding error for arithmetic operations. Depending on the
-// platform the mantissa precision may be different than others, so we choose to
-// use specific values to be consistent across all.
-// The values come from the C++ implementation.
-var (
- // epsilon is a small number that represents a reasonable level of noise between two
- // values that can be considered to be equal.
- epsilon = 1e-15
- // dblEpsilon is a smaller number for values that require more precision.
- dblEpsilon = 2.220446049e-16
-)
-
-// Expanded returns an interval that has been expanded on each side by margin.
-// If margin is negative, then the function shrinks the interval on
-// each side by margin instead. The resulting interval may be empty or
-// full. Any expansion (positive or negative) of a full interval remains
-// full, and any expansion of an empty interval remains empty.
-func (i Interval) Expanded(margin float64) Interval {
- if margin >= 0 {
- if i.IsEmpty() {
- return i
- }
- // Check whether this interval will be full after expansion, allowing
- // for a rounding error when computing each endpoint.
- if i.Length()+2*margin+2*dblEpsilon >= 2*math.Pi {
- return FullInterval()
- }
- } else {
- if i.IsFull() {
- return i
- }
- // Check whether this interval will be empty after expansion, allowing
- // for a rounding error when computing each endpoint.
- if i.Length()+2*margin-2*dblEpsilon <= 0 {
- return EmptyInterval()
- }
- }
- result := IntervalFromEndpoints(
- math.Remainder(i.Lo-margin, 2*math.Pi),
- math.Remainder(i.Hi+margin, 2*math.Pi),
- )
- if result.Lo <= -math.Pi {
- result.Lo = math.Pi
- }
- return result
-}
-
-// ApproxEqual reports whether this interval can be transformed into the given
-// interval by moving each endpoint by at most ε, without the
-// endpoints crossing (which would invert the interval). Empty and full
-// intervals are considered to start at an arbitrary point on the unit circle,
-// so any interval with (length <= 2*ε) matches the empty interval, and
-// any interval with (length >= 2*π - 2*ε) matches the full interval.
-func (i Interval) ApproxEqual(other Interval) bool {
- // Full and empty intervals require special cases because the endpoints
- // are considered to be positioned arbitrarily.
- if i.IsEmpty() {
- return other.Length() <= 2*epsilon
- }
- if other.IsEmpty() {
- return i.Length() <= 2*epsilon
- }
- if i.IsFull() {
- return other.Length() >= 2*(math.Pi-epsilon)
- }
- if other.IsFull() {
- return i.Length() >= 2*(math.Pi-epsilon)
- }
-
- // The purpose of the last test below is to verify that moving the endpoints
- // does not invert the interval, e.g. [-1e20, 1e20] vs. [1e20, -1e20].
- return (math.Abs(math.Remainder(other.Lo-i.Lo, 2*math.Pi)) <= epsilon &&
- math.Abs(math.Remainder(other.Hi-i.Hi, 2*math.Pi)) <= epsilon &&
- math.Abs(i.Length()-other.Length()) <= 2*epsilon)
-
-}
-
-func (i Interval) String() string {
- // like "[%.7f, %.7f]"
- return "[" + strconv.FormatFloat(i.Lo, 'f', 7, 64) + ", " + strconv.FormatFloat(i.Hi, 'f', 7, 64) + "]"
-}
-
-// Complement returns the complement of the interior of the interval. An interval and
-// its complement have the same boundary but do not share any interior
-// values. The complement operator is not a bijection, since the complement
-// of a singleton interval (containing a single value) is the same as the
-// complement of an empty interval.
-func (i Interval) Complement() Interval {
- if i.Lo == i.Hi {
- // Singleton. The interval just contains a single point.
- return FullInterval()
- }
- // Handles empty and full.
- return Interval{i.Hi, i.Lo}
-}
-
-// ComplementCenter returns the midpoint of the complement of the interval. For full and empty
-// intervals, the result is arbitrary. For a singleton interval (containing a
-// single point), the result is its antipodal point on S1.
-func (i Interval) ComplementCenter() float64 {
- if i.Lo != i.Hi {
- return i.Complement().Center()
- }
- // Singleton. The interval just contains a single point.
- if i.Hi <= 0 {
- return i.Hi + math.Pi
- }
- return i.Hi - math.Pi
-}
-
-// DirectedHausdorffDistance returns the Hausdorff distance to the given interval.
-// For two intervals i and y, this distance is defined by
-// h(i, y) = max_{p in i} min_{q in y} d(p, q),
-// where d(.,.) is measured along S1.
-func (i Interval) DirectedHausdorffDistance(y Interval) Angle {
- if y.ContainsInterval(i) {
- return 0 // This includes the case i is empty.
- }
- if y.IsEmpty() {
- return Angle(math.Pi) // maximum possible distance on s1.
- }
- yComplementCenter := y.ComplementCenter()
- if i.Contains(yComplementCenter) {
- return Angle(positiveDistance(y.Hi, yComplementCenter))
- }
-
- // The Hausdorff distance is realized by either two i.Hi endpoints or two
- // i.Lo endpoints, whichever is farther apart.
- hiHi := 0.0
- if IntervalFromEndpoints(y.Hi, yComplementCenter).Contains(i.Hi) {
- hiHi = positiveDistance(y.Hi, i.Hi)
- }
-
- loLo := 0.0
- if IntervalFromEndpoints(yComplementCenter, y.Lo).Contains(i.Lo) {
- loLo = positiveDistance(i.Lo, y.Lo)
- }
-
- return Angle(math.Max(hiHi, loLo))
-}
-
-// Project returns the closest point in the interval to the given point p.
-// The interval must be non-empty.
-func (i Interval) Project(p float64) float64 {
- if p == -math.Pi {
- p = math.Pi
- }
- if i.fastContains(p) {
- return p
- }
- // Compute distance from p to each endpoint.
- dlo := positiveDistance(p, i.Lo)
- dhi := positiveDistance(i.Hi, p)
- if dlo < dhi {
- return i.Lo
- }
- return i.Hi
-}