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Example solution to the Fresh8 Gaming ML Workshop challenge (https://github.com/fresh8/mlworkshop)
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| import ( | |
| "log" | |
| "math" | |
| "github.com/fresh8/mlworkshop/harness" | |
| "gonum.org/v1/gonum/floats" | |
| "gonum.org/v1/gonum/mat" | |
| ) | |
| func main() { | |
| log.Println("Evaluating KNN model") | |
| model := KNNClassifier{ | |
| K: 2, | |
| Distance: EuclideanDistance, | |
| } | |
| result, err := harness.Evaluate("diabetes.csv", &model) | |
| if err != nil { | |
| log.Fatal(err) | |
| } | |
| log.Printf("Result = %+v", result) | |
| } | |
| func EuclideanDistance(a, b mat.Vector) float64 { | |
| var v mat.VecDense | |
| v.SubVec(a, b) | |
| return math.Sqrt(mat.Dot(&v, &v)) | |
| } | |
| type KNNClassifier struct { | |
| K int | |
| Distance func(a, b mat.Vector) float64 | |
| datapoints *mat.Dense | |
| classes []string | |
| } | |
| func (k *KNNClassifier) Fit(X *mat.Dense, Y []string) { | |
| k.datapoints = X | |
| k.classes = Y | |
| } | |
| func (k *KNNClassifier) Predict(X *mat.Dense) []string { | |
| r, _ := X.Dims() | |
| targets := make([]string, r) | |
| distances := make([]float64, len(k.classes)) | |
| inds := make([]int, len(k.classes)) | |
| for i := 0; i < r; i++ { | |
| votes := make(map[string]float64) | |
| for j := 0; j < len(k.classes); j++ { | |
| distances[j] = k.Distance(k.datapoints.RowView(j), X.RowView(i)) | |
| } | |
| floats.Argsort(distances, inds) | |
| for n := 0; n < k.K; n++ { | |
| votes[k.classes[inds[n]]]++ | |
| } | |
| var winningCount float64 | |
| for k, v := range votes { | |
| if v > winningCount { | |
| targets[i] = k | |
| winningCount = v | |
| } | |
| } | |
| } | |
| return targets | |
| } |
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