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|
package climb
import (
"log/slog"
"math"
"slices"
"github.com/martinlehoux/biking_home/geo"
"github.com/martinlehoux/kagamigo/kcore"
)
type DetectedClimb struct {
Climb Climb
Start int
}
// returns the detected climbs but never a climb that overlaps a claimed range.
func Detect(route Route, claimed []geo.Interval, minSlope float64) []DetectedClimb {
distances, elevations, coords := route.Distances, route.Elevations, route.Coords
bounds := make([]geo.Interval, 0)
for _, region := range freeRegions(0, len(distances)-1, claimed) {
bounds = append(bounds, climbsBetween(distances, elevations, geo.NewInterval(region.Start, region.End), minSlope)...)
}
slices.SortFunc(bounds, func(a, b geo.Interval) int { return a.Start - b.Start })
climbs := make([]DetectedClimb, 0, len(bounds))
for _, b := range bounds {
climbs = append(climbs, DetectedClimb{
Climb: Climb{Route: Route{
Distances: distances[b.Start : b.End+1],
Elevations: elevations[b.Start : b.End+1],
Coords: coords[b.Start : b.End+1],
}},
Start: b.Start,
})
}
return climbs
}
// freeRegions returns the maximal sub-ranges of [rStart, rEnd] that are not
// covered by any claimed range, after discarding claims that fall outside.
func freeRegions(rStart, rEnd int, claimed []geo.Interval) []geo.Interval {
valid := make([]geo.Interval, 0, len(claimed))
for _, claim := range claimed {
// Discard claims outside the route or with a degenerate range.
if claim.Start < 0 || claim.End >= rEnd+1 || claim.Start >= claim.End {
continue
}
valid = append(valid, claim)
}
slices.SortFunc(valid, func(a, b geo.Interval) int { return a.Start - b.Start })
regions := make([]geo.Interval, 0, len(valid)+1)
current := rStart
for _, claim := range valid {
if claim.End < current {
continue
}
if claim.Start > current {
regions = append(regions, geo.NewInterval(current, claim.Start-1))
}
if claim.End+1 > current {
current = claim.End + 1
}
}
if current <= rEnd {
regions = append(regions, geo.NewInterval(current, rEnd))
}
return regions
}
// climbsBetween returns the detected climb bounds inside bounds from the
// distance and elevation components.
func climbsBetween(distances, elevations []float64, bounds geo.Interval, minSlope float64) []geo.Interval {
start, end := bounds.Start, bounds.End
climbs := []geo.Interval{}
if distances[end]-distances[start] < ClimbDistanceMinimum {
return climbs
}
slog.Debug("Searching climbs between", slog.Int("start", int(distances[start])), slog.Int("end", int(distances[end])))
highest := start
for i := start; i <= end; i++ {
if elevations[i] > elevations[highest] {
highest = i
}
}
// TODO: Use descent to reduce recursion
if distances[highest]-distances[start] < ClimbDistanceMinimum {
return climbsBetween(distances, elevations, geo.NewInterval(start+1, end), minSlope)
}
climb, found := bestClimbBetween(distances[start:highest+1], elevations[start:highest+1], minSlope)
if !found {
// No qualifying climb up to the top; only the part past it can hold climbs.
return climbsBetween(distances, elevations, geo.NewInterval(highest, end), minSlope)
}
// bestClimbBetween returns an interval relative to its sliced input;
// re-anchor it into this slice's index space.
climbStart := start + climb.Start
climbEnd := start + climb.End
if climbDetectionScore(distances[climbStart:climbEnd+1], elevations[climbStart:climbEnd+1]) >= detectionMinimumScore && distances[climbEnd]-distances[climbStart] >= ClimbDistanceMinimum {
slog.Debug("Found climb between", slog.Int("start", int(distances[climbStart])), slog.Int("end", int(distances[climbEnd])))
climbs = append(climbs, geo.NewInterval(climbStart, climbEnd))
}
climbs = append(climbs, climbsBetween(distances, elevations, geo.NewInterval(start, climbStart), minSlope)...)
climbs = append(climbs, climbsBetween(distances, elevations, geo.NewInterval(climbEnd, end), minSlope)...)
return climbs
}
func climbDetectionScore(distances, elevations []float64) float64 {
kcore.Assert(len(distances) > 0, "no points for climb detection")
end := len(distances) - 1
distance := distances[end] - distances[0]
if distance == 0 {
return 0
}
dElevation := elevations[end] - elevations[0]
return math.Abs(dElevation) * dElevation / distance * 100.0 * 100.0 / 1000.0
}
// bestClimbBetween returns the highest-scoring sub-interval of the segment
// given by [0, len-1]; when that climb averages below minSlope, it instead
// returns the best qualifying sub-segment (found=false when none exists). The
// returned interval is relative to the start of the given (already sliced)
// slices; callers add back their offset to recover absolute indices.
func bestClimbBetween(distances, elevations []float64, minSlope float64) (geo.Interval, bool) {
end := len(distances) - 1
kcore.Assert(end > 0, "empty points")
bestDetectionScore := climbDetectionScore(distances, elevations)
best := geo.NewInterval(0, end)
for i := range end {
detectionScore := climbDetectionScore(distances[i:end], elevations[i:end])
if detectionScore > bestDetectionScore {
best.Start = i
bestDetectionScore = detectionScore
}
}
for i := end; i > best.Start; i-- {
detectionScore := climbDetectionScore(distances[best.Start:i+1], elevations[best.Start:i+1])
if detectionScore > bestDetectionScore {
best.End = i
bestDetectionScore = detectionScore
}
}
for i := best.Start; i < best.End; i++ {
detectionScore := climbDetectionScore(distances[i:best.End], elevations[i:best.End])
if detectionScore > bestDetectionScore {
best.Start = i
bestDetectionScore = detectionScore
}
}
kcore.Assert(best.Start < best.End, "empty climb")
if minSlope <= 0 || Slope(distances[best.Start:best.End+1], elevations[best.Start:best.End+1]) >= minSlope {
return best, true
}
// Classic best too gentle: re-segment into the best qualifying sub-segment.
bestDetectionScore = math.Inf(-1)
best = geo.NewInterval(-1, -1)
for i := range end {
for j := i + 1; j <= end; j++ {
if Slope(distances[i:j+1], elevations[i:j+1]) < minSlope {
continue
}
detectionScore := climbDetectionScore(distances[i:j+1], elevations[i:j+1])
if detectionScore > bestDetectionScore {
bestDetectionScore = detectionScore
best.Start = i
best.End = j
}
}
}
if best.Start < 0 {
return geo.Interval{}, false
}
return best, true
}
|
