add seed param to search params (#168)

src/cluster/kmeans.rs

@@ -145,6 +145,9 @@ pub struct KMeansSearchParameters {
     pub k: Vec<usize>,
     /// Maximum number of iterations of the k-means algorithm for a single run.
     pub max_iter: Vec<usize>,
+    /// Determines random number generation for centroid initialization.
+    /// Use an int to make the randomness deterministic
+    pub seed: Vec<Option<u64>>,
 }
 
 /// KMeans grid search iterator
@@ -152,6 +155,7 @@ pub struct KMeansSearchParametersIterator {
     kmeans_search_parameters: KMeansSearchParameters,
     current_k: usize,
     current_max_iter: usize,
+    current_seed: usize,
 }
 
 impl IntoIterator for KMeansSearchParameters {
@@ -163,6 +167,7 @@ impl IntoIterator for KMeansSearchParameters {
             kmeans_search_parameters: self,
             current_k: 0,
             current_max_iter: 0,
+            current_seed: 0,
         }
     }
 }
@@ -173,6 +178,7 @@ impl Iterator for KMeansSearchParametersIterator {
     fn next(&mut self) -> Option<Self::Item> {
         if self.current_k == self.kmeans_search_parameters.k.len()
             && self.current_max_iter == self.kmeans_search_parameters.max_iter.len()
+            && self.current_seed == self.kmeans_search_parameters.seed.len()
         {
             return None;
         }
@@ -180,6 +186,7 @@ impl Iterator for KMeansSearchParametersIterator {
         let next = KMeansParameters {
             k: self.kmeans_search_parameters.k[self.current_k],
             max_iter: self.kmeans_search_parameters.max_iter[self.current_max_iter],
+            seed: self.kmeans_search_parameters.seed[self.current_seed],
         };
 
         if self.current_k + 1 < self.kmeans_search_parameters.k.len() {
@@ -187,9 +194,14 @@ impl Iterator for KMeansSearchParametersIterator {
         } else if self.current_max_iter + 1 < self.kmeans_search_parameters.max_iter.len() {
             self.current_k = 0;
             self.current_max_iter += 1;
+        } else if self.current_seed + 1 < self.kmeans_search_parameters.seed.len() {
+            self.current_k = 0;
+            self.current_max_iter = 0;
+            self.current_seed += 1;
         } else {
             self.current_k += 1;
             self.current_max_iter += 1;
+            self.current_seed += 1;
         }
 
         Some(next)
@@ -203,6 +215,7 @@ impl Default for KMeansSearchParameters {
         KMeansSearchParameters {
             k: vec![default_params.k],
             max_iter: vec![default_params.max_iter],
+            seed: vec![default_params.seed],
         }
     }
 }