Fix clippy errors

src/algorithm/neighbour/cover_tree.rs

@@ -101,7 +101,7 @@ impl<T: Debug + PartialEq, F: RealNumber, D: Distance<T, F>> CoverTree<T, F, D>
     /// * `p` - look for k nearest points to `p`
     /// * `k` - the number of nearest neighbors to return
     pub fn find(&self, p: &T, k: usize) -> Result<Vec<(usize, F, &T)>, Failed> {
-        if k <= 0 {
+        if k == 0 {
             return Err(Failed::because(FailedError::FindFailed, "k should be > 0"));
         }
 

src/cluster/kmeans.rs

@@ -129,7 +129,7 @@ impl<T: RealNumber + Sum> KMeans<T> {
             return Err(Failed::fit(&format!("invalid number of clusters: {}", k)));
         }
 
-        if parameters.max_iter <= 0 {
+        if parameters.max_iter == 0 {
             return Err(Failed::fit(&format!(
                 "invalid maximum number of iterations: {}",
                 parameters.max_iter

src/dataset/mod.rs

@@ -56,8 +56,8 @@ pub(crate) fn serialize_data<X: RealNumber, Y: RealNumber>(
 ) -> Result<(), io::Error> {
     match File::create(filename) {
         Ok(mut file) => {
-            file.write(&dataset.num_features.to_le_bytes())?;
-            file.write(&dataset.num_samples.to_le_bytes())?;
+            file.write_all(&dataset.num_features.to_le_bytes())?;
+            file.write_all(&dataset.num_samples.to_le_bytes())?;
             let x: Vec<u8> = dataset
                 .data
                 .iter()