Fix division by zero exception (#11)

mhdcodes · web-flow · commit e9cb06766c6d · 2023-10-05T13:33:27.000+01:00
* Fix division by zero in slopeone predictor

* Fix styling
diff --git a/composer.json b/composer.json
@@ -24,9 +24,9 @@
         "php": "^7.4|^8.0|^8.1"
     },
     "require-dev": {
-        "squizlabs/php_codesniffer": "^3.4",
-        "phpstan/phpstan": "^0.12",
-        "pestphp/pest": "^1.18"
+        "phpstan/phpstan": "^1.10",
+        "pestphp/pest": "^1.23",
+        "friendsofphp/php-cs-fixer": "^3.34"
     },
     "autoload": {
         "psr-4": {
diff --git a/src/Algorithms/Slopeone/Predictor.php b/src/Algorithms/Slopeone/Predictor.php
@@ -35,7 +35,8 @@ public function getPrediction(array $evaluation, string $target): float
             $sum += ($value + $vectors[1][$key]) * $card;
             $freq += $card;
         }
-        $predValue = $sum / $freq;
+
+        $predValue = $sum / ($freq !== 0 ? $freq : 1);
 
         return round($predValue, $this->vector->getScale());
     }

Original file line number	Diff line number	Diff line change
`@@ -35,7 +35,8 @@ public function getPrediction(array $evaluation, string $target): float`
`35`	`35`	`$sum += ($value + $vectors[1][$key]) * $card;`
`36`	`36`	`$freq += $card;`
`37`	`37`	`}`
`38`		`- $predValue = $sum / $freq;`
	`38`	`+`
	`39`	`+ $predValue = $sum / ($freq !== 0 ? $freq : 1);`
`39`	`40`
`40`	`41`	`return round($predValue, $this->vector->getScale());`
`41`	`42`	`}`