diff --git a/src/Frontend/LayoutEngine/Measure/Measurer/GridMeasurer.php b/src/Frontend/LayoutEngine/Measure/Measurer/GridMeasurer.php
index 577874f..683df88 100644
--- a/src/Frontend/LayoutEngine/Measure/Measurer/GridMeasurer.php
+++ b/src/Frontend/LayoutEngine/Measure/Measurer/GridMeasurer.php
@@ -49,6 +49,7 @@ public function measure(array $rows, array $columnSizes, float $gap, float $perp
 
             $minHeight = max($minHeight, $measuredColumnFirstRow->getMinHeight());
 
+            $averageDimension = 0.0;
             $measuredColumn = $this->measureColumn($rows, $columnIndex, $measuredColumnFirstRow, $averageDimension);
             $totalDimensions += $averageDimension;
             $totalWeight += $measuredColumn->getWeight();
diff --git a/src/Utils/TransformationMatrixCalculator.php b/src/Utils/TransformationMatrixCalculator.php
index 4917dde..bc7da27 100644
--- a/src/Utils/TransformationMatrixCalculator.php
+++ b/src/Utils/TransformationMatrixCalculator.php
@@ -87,7 +87,7 @@ private static function LUDecompose(array $matrix): array
             // Find pivot and exchange if necessary.
             $p = $j;
             for ($i = $j + 1; $i < 3; ++$i) {
-                if (abs($LUcolj[$i] ?? 0) > abs($LUcolj[$p] ?? 0)) {
+                if (abs($LUcolj[$i]) > abs($LUcolj[$p])) {
                     $p = $i;
                 }
             }