Added fromMap function to SparseVector

src/SparseVector.php

@@ -32,6 +32,21 @@ public static function fromDense($value)
         return new SparseVector($dimensions, $indices, $values);
     }
 
+    public static function fromMap($map, $dimensions)
+    {
+        $indices = [];
+        $values = [];
+        // no need to sort since binary format is not supported
+        foreach ($map as $i => $v) {
+            $fv = floatval($v);
+            if ($fv != 0) {
+                $indices[] = intval($i);
+                $values[] = $fv;
+            }
+        }
+        return new SparseVector($dimensions, $indices, $values);
+    }
+
     public static function fromString($value)
     {
         $parts = explode('/', $value, 2);

tests/SparseVectorTest.php

@@ -14,6 +14,12 @@ public function testFromDense()
         $this->assertEquals([1, 2, 3], $embedding->values());
     }
 
+    public function testFromMap()
+    {
+        $embedding = SparseVector::fromMap([2 => 2, 4 => 3, 0 => 1, 3 => 0], 6);
+        $this->assertEquals([1, 0, 2, 0, 3, 0], $embedding->toArray());
+    }
+
     public function testFromString()
     {
         $embedding = SparseVector::fromString('{1:1,3:2,5:3}/6');