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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,76 @@ | ||
| package tsp | ||
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| // https://github.com/medchik/Travelling-Salesman-Problem-Approximate-Solution-using-MST | ||
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| const INT_MAX = float64(1e9) | ||
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| type MST struct { | ||
| } | ||
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| func (MST) optimizeRoute(matrix [][]float64) (float64, []int) { | ||
| var n = len(matrix) | ||
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| var rootNode int | ||
| var reached []int | ||
| var unreached []int | ||
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| var tree = make([][]int, n) | ||
| for i := 0; i < n; i++ { | ||
| tree[i] = []int{} | ||
| } | ||
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| unreached = make([]int, n) | ||
| for i := 0; i < n; i++ { | ||
| unreached[i] = i | ||
| } | ||
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| var path = []int{} | ||
| var cost = float64(0) | ||
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| prim := func() { | ||
| var max float64 | ||
| var record float64 | ||
| var parent int | ||
| var newNode int | ||
| var indexNewNode int | ||
| rootNode = unreached[0] | ||
| reached = append(reached, unreached[0]) | ||
| unreached = append(unreached[:0], unreached[1:]...) | ||
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| for len(unreached) > 0 { | ||
| max = INT_MAX | ||
| for i := 0; i < len(reached); i++ { | ||
| for j := 0; j < len(unreached); j++ { | ||
| record = matrix[reached[i]][unreached[j]] | ||
| if record < max { | ||
| max = record | ||
| indexNewNode = j | ||
| parent = reached[i] | ||
| newNode = unreached[j] | ||
| } | ||
| } | ||
| } | ||
| reached = append(reached, unreached[indexNewNode]) | ||
| unreached = append(unreached[:indexNewNode], unreached[indexNewNode+1:]...) | ||
| tree[parent] = append(tree[parent], newNode) | ||
| } | ||
| } | ||
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| var preorder func(index int) | ||
| preorder = func(index int) { | ||
| path = append(path, index) | ||
| for _, i := range tree[index] { | ||
| preorder(i) | ||
| } | ||
| } | ||
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| prim() | ||
| preorder(rootNode) | ||
| path = append(path, rootNode) // to create the cycle | ||
| for i := 0; i < len(path)-1; i++ { | ||
| src := path[i] | ||
| dest := path[i+1] | ||
| cost = cost + matrix[src][dest] | ||
| } | ||
| return cost, path | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,113 @@ | ||
| package tsp | ||
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| import ( | ||
| "math" | ||
| "time" | ||
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| "github.com/the-clothing-loop/website/server/internal/app/goscope" | ||
| "gorm.io/gorm" | ||
| ) | ||
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| type TSPAlgorithm interface { | ||
| optimizeRoute(matrix [][]float64) (float64, []int) | ||
| } | ||
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| type UserChain struct { | ||
| UserID uint | ||
| UserUID string | ||
| UserLatitude float64 | ||
| UserLongitude float64 | ||
| IsChainAdmin bool | ||
| CreatedAt time.Time | ||
| } | ||
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| var optimizer TSPAlgorithm = MST{} | ||
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| /* | ||
| * | ||
| Given a ChainUID return an optimized route for all the approved participant of the loop | ||
| with latitude and longitude. | ||
| * | ||
| */ | ||
| func OptimizeRoute(ChainID uint, db *gorm.DB) (float64, []string) { | ||
| users := retrieveChainUsers(ChainID, db) | ||
| distanceMatrix := createDistanceMatrix(users) | ||
| minimalCost, optimalPath := optimizer.optimizeRoute(distanceMatrix) | ||
| // obtaining the uid of the users based in his index in the optimalPath | ||
| orderedUsersId := sortUsersByOptimalPath(users, optimalPath) | ||
| return minimalCost, orderedUsersId | ||
| } | ||
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| func retrieveChainUsers(ChainID uint, db *gorm.DB) []UserChain { | ||
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| allUserChains := &[]UserChain{} | ||
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| err := db.Raw(` | ||
| SELECT | ||
| users.id AS user_id, | ||
| users.uid AS user_uid, | ||
| users.latitude AS user_latitude, | ||
| users.longitude AS user_longitude, | ||
| user_chains.is_chain_admin AS is_chain_admin, | ||
| user_chains.created_at AS created_at | ||
| FROM user_chains | ||
| LEFT JOIN users ON user_chains.user_id = users.id | ||
| WHERE user_chains.chain_id = ? | ||
| AND users.is_email_verified = TRUE | ||
| AND user_chains.is_approved = TRUE | ||
| AND users.latitude <> 0 AND users.longitude <> 0 `, ChainID).Scan(allUserChains).Error | ||
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| if err != nil { | ||
| goscope.Log.Errorf("Unable to retrieve associations between a loop and its users: %v", err) | ||
| return nil | ||
| } | ||
| return *allUserChains | ||
| } | ||
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| func createDistanceMatrix(users []UserChain) [][]float64 { | ||
| n := len(users) | ||
| matrix := make([][]float64, n) | ||
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| for i := 0; i < n; i++ { | ||
| matrix[i] = make([]float64, n) | ||
| } | ||
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| for i := 0; i < n; i++ { | ||
| for j := i; j < n; j++ { | ||
| distance := calculateDistance(users[i], users[j]) | ||
| matrix[i][j] = distance | ||
| matrix[j][i] = distance | ||
| } | ||
| } | ||
| return matrix | ||
| } | ||
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| func calculateDistance(user1, user2 UserChain) float64 { | ||
| lat1 := user1.UserLatitude | ||
| lon1 := user1.UserLongitude | ||
| lat2 := user2.UserLatitude | ||
| lon2 := user2.UserLongitude | ||
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| // Calculate distance using Haversine formula | ||
| dLat := toRadians(lat2 - lat1) | ||
| dLon := toRadians(lon2 - lon1) | ||
| a := math.Sin(dLat/2)*math.Sin(dLat/2) + math.Cos(toRadians(lat1))*math.Cos(toRadians(lat2))*math.Sin(dLon/2)*math.Sin(dLon/2) | ||
| c := 2 * math.Atan2(math.Sqrt(a), math.Sqrt(1-a)) | ||
| distance := 6371 * c // Earth's radius in kilometers | ||
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| return distance | ||
| } | ||
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| func toRadians(degrees float64) float64 { | ||
| return degrees * math.Pi / 180 | ||
| } | ||
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| func sortUsersByOptimalPath(users []UserChain, optimalPath []int) []string { | ||
| orderedUsersId := make([]string, len(users)) | ||
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| for i := 0; i < len(users); i++ { | ||
| userIndex := optimalPath[i] | ||
| orderedUsersId[i] = users[userIndex].UserUID | ||
| } | ||
| return orderedUsersId | ||
| } |