[DOC][1/2] Documentation for builtin KMeans function
Closes #933.
diff --git a/dev/docs/builtins-reference.md b/dev/docs/builtins-reference.md
index 6ca4870..4346883 100644
--- a/dev/docs/builtins-reference.md
+++ b/dev/docs/builtins-reference.md
@@ -23,6 +23,7 @@
* [Built-In Construction Functions](#built-in-construction-functions)
* [`tensor`-Function](#tensor-function)
* [DML-Bodied Built-In functions](#dml-bodied-built-in-functions)
+ * [`KMeans`-Function](#KMeans-function)
* [`lm`-Function](#lm-function)
* [`lmDS`-Function](#lmds-function)
* [`lmCG`-Function](#lmcg-function)
@@ -114,6 +115,32 @@
**DML-bodied built-in functions** are written as DML-Scripts and executed as such when called.
+## `KMeans`-Function
+
+The kmeans() implements the KMeans Clustering algorithm.
+
+### Usage
+```r
+kmeans(X = X, k = 20, runs = 10, max_iter = 5000, eps = 0.000001, is_verbose = FALSE, avg_sample_size_per_centroid = 50)
+```
+
+### Arguments
+| Name | Type | Default | Description |
+| :--------- | :-------------- | :--------- | :---------- |
+| x | Matrix[Double] | required | The input Matrix to do KMeans on. |
+| k | Int | `10` | Number of centroids |
+| runs | Int | `10` | Number of runs (with different initial centroids) |
+| max_iter | Int | `100` |Max no. of iterations allowed |
+| eps | Double | `0.000001` | Tolerance (epsilon) for WCSS change ratio |
+| is_verbose | Boolean | FALSE | do not print per-iteration stats |
+
+### Returns
+| Type | Description |
+| :----- | :---------- |
+| String | The mapping of records to centroids |
+| String | The output matrix with the centroids |
+
+
## `lm`-Function
The `lm`-function solves linear regression using either the **direct solve method** or the **conjugate gradient algorithm**
