From 665a3d1d23ce3ff63d7160070ccc41f947fc8261 Mon Sep 17 00:00:00 2001
From: Andrew DalPino <andrewdalpino@users.noreply.github.com>
Date: Tue, 18 Jul 2023 18:10:45 -0500
Subject: [PATCH] Initial commit (#299)

---
 CHANGELOG.md                           |  3 ++
 docs/datasets/generators/blob.md       | 12 ++++++--
 src/Datasets/Generators/Blob.php       | 42 ++++++++++++++++++++++++++
 src/NeuralNet/Snapshotter.php          |  0
 tests/Datasets/Generators/BlobTest.php | 21 +++++++++++++
 5 files changed, 76 insertions(+), 2 deletions(-)
 delete mode 100644 src/NeuralNet/Snapshotter.php

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3a3fcbfa5..b5ba4d025 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,6 @@
+- 2.5.0
+    - Blob Generator can now `simulate()` a Dataset object
+
 - 2.4.1
     - Sentence Tokenizer fix Arabic and Farsi language support
 
diff --git a/docs/datasets/generators/blob.md b/docs/datasets/generators/blob.md
index a0a8cbe4e..e99bf65ab 100644
--- a/docs/datasets/generators/blob.md
+++ b/docs/datasets/generators/blob.md
@@ -17,8 +17,16 @@ A normally distributed (Gaussian) n-dimensional blob of samples centered at a gi
 ```php
 use Rubix\ML\Datasets\Generators\Blob;
 
-$generator = new Blob([-1.2, -5., 2.6, 0.8, 10.], 0.25);
+$generator = new Blob([-1.2, -5.0, 2.6, 0.8, 10.0], 0.25);
 ```
 
 ## Additional Methods
-This generator does not have any additional methods.
+Fit a Blob generator to the samples in a dataset.
+```php
+public static simulate(Dataset $dataset) : self
+```
+
+Return the center coordinates of the Blob.
+```php
+public center() : array
+```
diff --git a/src/Datasets/Generators/Blob.php b/src/Datasets/Generators/Blob.php
index 7bf65adbd..0b9ce5250 100644
--- a/src/Datasets/Generators/Blob.php
+++ b/src/Datasets/Generators/Blob.php
@@ -4,10 +4,14 @@
 
 use Tensor\Matrix;
 use Tensor\Vector;
+use Rubix\ML\DataType;
+use Rubix\ML\Helpers\Stats;
+use Rubix\ML\Datasets\Dataset;
 use Rubix\ML\Datasets\Unlabeled;
 use Rubix\ML\Exceptions\InvalidArgumentException;
 
 use function count;
+use function sqrt;
 
 /**
  * Blob
@@ -37,6 +41,34 @@ class Blob implements Generator
      */
     protected $stdDev;
 
+    /**
+     * Fit a Blob generator to the samples in a dataset.
+     *
+     * @param \Rubix\ML\Datasets\Dataset $dataset
+     * @throws \Rubix\ML\Exceptions\InvalidArgumentException
+     * @return self
+     */
+    public static function simulate(Dataset $dataset) : self
+    {
+        $features = $dataset->featuresByType(DataType::continuous());
+
+        if (count($features) !== $dataset->numFeatures()) {
+            throw new InvalidArgumentException('Dataset must only contain'
+                . ' continuous features.');
+        }
+
+        $means = $stdDevs = [];
+
+        foreach ($features as $values) {
+            [$mean, $variance] = Stats::meanVar($values);
+
+            $means[] = $mean;
+            $stdDevs[] = sqrt($variance);
+        }
+
+        return new self($means, $stdDevs);
+    }
+
     /**
      * @param (int|float)[] $center
      * @param int|float|(int|float)[] $stdDev
@@ -74,6 +106,16 @@ public function __construct(array $center = [0, 0], $stdDev = 1.0)
         $this->stdDev = $stdDev;
     }
 
+    /**
+     * Return the center coordinates of the Blob.
+     *
+     * @return list<int|float>
+     */
+    public function center() : array
+    {
+        return $this->center->asArray();
+    }
+
     /**
      * Return the dimensionality of the data this generates.
      *
diff --git a/src/NeuralNet/Snapshotter.php b/src/NeuralNet/Snapshotter.php
deleted file mode 100644
index e69de29bb..000000000
diff --git a/tests/Datasets/Generators/BlobTest.php b/tests/Datasets/Generators/BlobTest.php
index 1dcd39055..b5ea3631c 100644
--- a/tests/Datasets/Generators/BlobTest.php
+++ b/tests/Datasets/Generators/BlobTest.php
@@ -29,6 +29,19 @@ protected function setUp() : void
         $this->generator = new Blob([0, 0, 0], 1.0);
     }
 
+    /**
+     * @test
+     */
+    public function simulate() : void
+    {
+        $dataset = $this->generator->generate(100);
+
+        $generator = Blob::simulate($dataset);
+
+        $this->assertInstanceOf(Blob::class, $generator);
+        $this->assertInstanceOf(Generator::class, $generator);
+    }
+
     /**
      * @test
      */
@@ -38,6 +51,14 @@ public function build() : void
         $this->assertInstanceOf(Generator::class, $this->generator);
     }
 
+    /**
+     * @test
+     */
+    public function center() : void
+    {
+        $this->assertEquals([0, 0, 0], $this->generator->center());
+    }
+
     /**
      * @test
      */