Very Minor Simplification to Matrix Functions (PHPOffice#2222)

The external Matrix library has introduced some changes which permit the matrix functions to be slightly simplified.

Author: oleibman

src/PhpSpreadsheet/Calculation/MathTrig/MatrixFunctions.php

@@ -3,6 +3,7 @@
 namespace PhpOffice\PhpSpreadsheet\Calculation\MathTrig;
 
 use Matrix\Builder;
+use Matrix\Div0Exception as MatrixDiv0Exception;
 use Matrix\Exception as MatrixException;
 use Matrix\Matrix;
 use PhpOffice\PhpSpreadsheet\Calculation\Exception;
@@ -84,8 +85,10 @@ public static function inverse($matrixValues)
             $matrix = self::getMatrix($matrixValues);
 
             return $matrix->inverse()->toArray();
+        } catch (MatrixDiv0Exception $e) {
+            return Functions::NAN();
         } catch (MatrixException $e) {
-            return (strpos($e->getMessage(), 'determinant') === false) ? Functions::VALUE() : Functions::NAN();
+            return Functions::VALUE();
         } catch (Exception $e) {
             return $e->getMessage();
         }
@@ -125,10 +128,7 @@ public static function identity($dimension)
         try {
             $dimension = (int) Helpers::validateNumericNullBool($dimension);
             Helpers::validatePositive($dimension, Functions::VALUE());
-            $matrix = Builder::createFilledMatrix(0, $dimension)->toArray();
-            for ($x = 0; $x < $dimension; ++$x) {
-                $matrix[$x][$x] = 1;
-            }
+            $matrix = Builder::createIdentityMatrix($dimension, 0)->toArray();
 
             return $matrix;
         } catch (Exception $e) {