Allow empty dataset objects in stack()

RubixML · Oct 30, 2021 · af69742 · af69742
1 parent ec2c41c
commit af69742
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Showing 5 changed files with 51 additions and 39 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -1,3 +1,6 @@
+- 1.2.2
+    - Allow empty dataset objects in `stack()`
+
 - 1.2.1
     - Refactor stratified methods on Labeled dataset
     - Narrower typehints

diff --git a/src/Datasets/Dataset.php b/src/Datasets/Dataset.php
@@ -104,10 +104,10 @@ abstract public static function fromIterator(iterable $iterator) : self;
     /**
      * Stack a number of datasets on top of each other to form a single dataset.
      *
-     * @param \Rubix\ML\Datasets\Dataset[] $datasets
+     * @param iterable<\Rubix\ML\Datasets\Dataset> $datasets
      * @return static
      */
-    abstract public static function stack(array $datasets) : self;
+    abstract public static function stack(iterable $datasets) : self;
 
     /**
      * Return a 2-tuple containing the shape of the sample matrix i.e the number of rows and columns.

diff --git a/src/Datasets/Labeled.php b/src/Datasets/Labeled.php
@@ -96,31 +96,35 @@ public static function fromIterator(iterable $iterator) : self
     /**
      * Stack a number of datasets on top of each other to form a single dataset.
      *
-     * @param \Rubix\ML\Datasets\Labeled[] $datasets
+     * @param iterable<\Rubix\ML\Datasets\Labeled> $datasets
      * @throws \Rubix\ML\Exceptions\InvalidArgumentException
      * @return self
      */
-    public static function stack(array $datasets) : self
+    public static function stack(iterable $datasets) : self
     {
-        $n = $datasets[array_key_first($datasets)]->numFeatures();
-
         $samples = $labels = [];
 
-        foreach ($datasets as $dataset) {
+        foreach ($datasets as $i => $dataset) {
             if (!$dataset instanceof Labeled) {
                 throw new InvalidArgumentException('Dataset must be'
                     . ' an instance of Labeled, ' . get_class($dataset)
                     . ' given.');
             }
 
-            if ($dataset->numFeatures() !== $n) {
-                throw new InvalidArgumentException('Dataset must have'
-                    . " the same number of columns, $n expected but "
-                    . $dataset->numFeatures() . ' given.');
+            if ($dataset->empty()) {
+                continue;
+            }
+
+            if (isset($lastNumFeatures) and $dataset->numFeatures() !== $lastNumFeatures) {
+                throw new InvalidArgumentException("Dataset $i must have"
+                    . " the same number of columns, $lastNumFeatures"
+                    . " expected but {$dataset->numFeatures()} given.");
             }
 
             $samples[] = $dataset->samples();
             $labels[] = $dataset->labels();
+
+            $lastNumFeatures = $dataset->numFeatures();
         }
 
         return self::quick(
@@ -463,16 +467,17 @@ public function split(float $ratio = 0.5) : array
 
         $n = (int) floor($ratio * $this->numSamples());
 
-        return [
-            self::quick(
-                array_slice($this->samples, 0, $n),
-                array_slice($this->labels, 0, $n)
-            ),
-            self::quick(
-                array_slice($this->samples, $n),
-                array_slice($this->labels, $n)
-            ),
-        ];
+        $left = self::quick(
+            array_slice($this->samples, 0, $n),
+            array_slice($this->labels, 0, $n)
+        );
+
+        $right = self::quick(
+            array_slice($this->samples, $n),
+            array_slice($this->labels, $n)
+        );
+
+        return [$left, $right];
     }
 
     /**
@@ -498,10 +503,10 @@ public function stratifiedSplit(float $ratio = 0.5) : array
             $rightStrata[] = $right;
         }
 
-        return [
-            self::stack($leftStrata),
-            self::stack($rightStrata),
-        ];
+        $left = self::stack($leftStrata);
+        $right = self::stack($rightStrata);
+
+        return [$left, $right];
     }
 
     /**

diff --git a/src/Datasets/Unlabeled.php b/src/Datasets/Unlabeled.php
@@ -68,29 +68,33 @@ public static function fromIterator(iterable $iterator) : self
     /**
      * Stack a number of datasets on top of each other to form a single dataset.
      *
-     * @param \Rubix\ML\Datasets\Dataset[] $datasets
+     * @param iterable<\Rubix\ML\Datasets\Dataset> $datasets
      * @throws \Rubix\ML\Exceptions\InvalidArgumentException
      * @return self
      */
-    public static function stack(array $datasets) : self
+    public static function stack(iterable $datasets) : self
     {
-        $n = $datasets[array_key_first($datasets)]->numFeatures();
-
         $samples = [];
 
-        foreach ($datasets as $dataset) {
+        foreach ($datasets as $i => $dataset) {
             if (!$dataset instanceof Dataset) {
                 throw new InvalidArgumentException('Dataset must implement'
                     . ' the Dataset interface.');
             }
 
-            if ($dataset->numFeatures() !== $n) {
-                throw new InvalidArgumentException('Dataset must have'
-                    . " the same number of columns, $n expected but"
-                    . " {$dataset->numFeatures()} given.");
+            if ($dataset->empty()) {
+                continue;
+            }
+
+            if (isset($lastNumFeatures) and $dataset->numFeatures() !== $lastNumFeatures) {
+                throw new InvalidArgumentException("Dataset $i must have"
+                    . " the same number of features, $lastNumFeatures"
+                    . " expected but {$dataset->numFeatures()} given.");
             }
 
             $samples[] = $dataset->samples();
+
+            $lastNumFeatures = $dataset->numFeatures();
         }
 
         return self::quick(array_merge(...$samples));
@@ -261,10 +265,10 @@ public function split(float $ratio = 0.5) : array
 
         $n = (int) floor($ratio * $this->numSamples());
 
-        return [
-            self::quick(array_slice($this->samples, 0, $n)),
-            self::quick(array_slice($this->samples, $n)),
-        ];
+        $left = self::quick(array_slice($this->samples, 0, $n));
+        $right = self::quick(array_slice($this->samples, $n));
+
+        return [$left, $right];
     }
 
     /**

diff --git a/src/constants.php b/src/constants.php
@@ -9,7 +9,7 @@
      *
      * @var string
      */
-    const VERSION = '1.2.1';
+    const VERSION = '1.2.2';
 
     /**
      * A small number used in substitution of 0.