added matrix 2x2 inverse

Matrix.hpp

@@ -128,6 +128,7 @@ class Matrix {
     }
 };
 
+using Mat22f = Matrix<float, 2, 2>;
 using Mat33f = Matrix<float, 3, 3>;
 using Mat44f = Matrix<float, 4, 4>;
 
@@ -171,6 +172,16 @@ Matrix<T, Rows, Cols> transpose(const Matrix<T, Cols, Rows>& m) {
     return tr;
 }
 
+inline Mat22f invert(const Mat22f& m) {
+    float invdet = 1.f / (m(0, 0) * m(1, 1) - m(0, 1) * m(1, 0));
+    Mat22f minv;
+    minv(0, 0) = m(1, 1) * invdet;
+    minv(0, 1) = -m(0, 1) * invdet;
+    minv(1, 0) = -m(1, 0) * invdet;
+    minv(1, 1) = m(0, 0) * invdet;
+    return minv;
+}
+
 inline Mat33f invert(const Mat33f& m) {
     double det = m(0, 0) * (m(1, 1) * m(2, 2) - m(2, 1) * m(1, 2)) -
                  m(0, 1) * (m(1, 0) * m(2, 2) - m(1, 2) * m(2, 0)) +

UniformGrid.hpp

@@ -61,7 +61,7 @@ class UniformGrid {
 
     UniformGrid(const Idxs& dims)
         : dims_(dims) {
-        data_.resize(voxelCount());
+        data_.resize(voxelCount(), Object());
     }
 
     Object& operator()(const Idxs& idxs) {
@@ -80,6 +80,10 @@ class UniformGrid {
         return cnt;
     }
 
+    Idxs dimension() const {
+        return dims_;
+    }
+
     GridIterator<Object, Dim> begin() {
         return { data_.data(), 0, dims_ };
     }
@@ -96,6 +100,10 @@ class UniformGrid {
         return { data_.data() + data_.size(), 0, dims_ };
     }
 
+    Object* data() {
+        return data_.data();
+    }
+
 private:
     std::size_t map(const Idxs& idxs) const {
         std::size_t linear = 0;