matrix: add method to check all values are nan (#82)

matrix/Matrix.hpp

@@ -507,6 +507,17 @@ public:
         return min_val;
     }
 
+    bool isAllNan() const {
+        const Matrix<float, M, N> &self = *this;
+        bool result = true;
+        for (size_t i = 0; i < M; i++) {
+            for (size_t j = 0; j < N; j++) {
+                result = result && isnan(self(i, j));
+            }
+        }
+        return result;
+    }
+
 };
 
 template<typename Type, size_t M, size_t N>

test/matrixAssignment.cpp

@@ -30,6 +30,7 @@ int main()
     for(int i=0; i<9; i++) {
         TEST(isnan(m_nan.data()[i]));
     }
+    TEST(m_nan.isAllNan());
 
     float data2d[3][3] = {
         {1, 2, 3},
@@ -40,6 +41,7 @@ int main()
     for(int i=0; i<9; i++) {
         TEST(fabs(data[i] - m2.data()[i]) < FLT_EPSILON);
     }
+    TEST(!m2.isAllNan());
 
     float data_times_2[9] = {2, 4, 6, 8, 10, 12, 14, 16, 18};
     Matrix3f m3(data_times_2);