Function for skipping given row and column from an matrix.

src/Math/Matrix.h

@@ -143,6 +143,19 @@ template<class T, size_t size> class Matrix {
             return out;
         }
 
+        /** @brief Matrix without given row and column */
+        Matrix<T, size-1> ij(size_t skipRow, size_t skipCol) const {
+            Matrix<T, size-1> out(false);
+
+            for(size_t row = 0; row != size-1; ++row) {
+                for(size_t col = 0; col != size-1; ++col)
+                    out.set(row, col, at(row + (row >= skipRow),
+                                         col + (col >= skipCol)));
+            }
+
+            return out;
+        }
+
     private:
         T _data[size*size];
 };

src/Math/Test/MatrixTest.cpp

@@ -24,6 +24,7 @@ QTEST_APPLESS_MAIN(Magnum::Math::Test::MatrixTest)
 namespace Magnum { namespace Math { namespace Test {
 
 typedef Matrix<float, 4> Matrix4;
+typedef Matrix<float, 3> Matrix3;
 
 void MatrixTest::constructIdentity() {
     Matrix4 identity;
@@ -171,4 +172,21 @@ void MatrixTest::transposed() {
     QVERIFY(Matrix4(original).transposed() == Matrix4(transposed));
 }
 
+void MatrixTest::ij() {
+    float original[] = {
+        0.0f,   1.0f,   2.0f,   3.0f,
+        4.0f,   5.0f,   6.0f,   7.0f,
+        8.0f,   9.0f,   10.0f,  11.0f,
+        12.0f,  13.0f,  14.0f,  15.0f
+    };
+
+    float skipped[] = {
+        0.0f,   1.0f,   3.0f,
+        8.0f,   9.0f,   11.0f,
+        12.0f,  13.0f,  15.0f
+    };
+
+    QVERIFY(Matrix4(original).ij(2, 1) == Matrix3(skipped));
+}
+
 }}}

src/Math/Test/MatrixTest.h

@@ -31,6 +31,7 @@ class MatrixTest: public QObject {
         void multiply();
         void multiplyVector();
         void transposed();
+        void ij();
 };
 
 }}}