[ADD] A member function to render a symmetric Matrix to a string. This will be...

[ADD] A member function to render a symmetric Matrix to a string. This will be needed to save them to plain text files.

src/core/common/math/WMatrixSym.h

@@ -71,6 +71,7 @@ public:
      * \return reference to the (i,j) element of the table
      */
     T& operator()( size_t i, size_t j ) throw( WOutOfBounds );
+    const T& operator()( size_t i, size_t j ) const throw( WOutOfBounds );
 
     /**
      * Returns the number of elements stored in this matrix.
@@ -98,6 +99,14 @@ public:
      */
     void setData( const std::vector< T > &data ) throw( WOutOfBounds );
 
+    /**
+     * Renders the matrix to a full nxn matrix, where the main diagonal is set to 0.0 and the m(i,j) == m(j,i).
+     * Each column is separated by exactly one space and each row is separated by a newline.
+     *
+     * @return Multiline string containing the nxn symmetric matrix.
+     */
+    std::string toString( void ) const;
+
 private:
     /**
      * Internal data structure to store the elements. The order is row major.
@@ -123,6 +132,23 @@ inline WMatrixSymImpl< T >::WMatrixSymImpl()
 {
 }
 
+template< typename T >
+inline const T& WMatrixSymImpl< T >::operator()( size_t i, size_t j ) const throw( WOutOfBounds )
+{
+    if( i == j || i >= m_n || j >= m_n )
+    {
+        std::stringstream ss;
+        ss << "Invalid Element Access ( " << i << ", " << j << " ). No diagonal elements or indices bigger than " << m_n << " are allowed.";
+        throw WOutOfBounds( ss.str() );
+    }
+    if( i > j )
+    {
+        std::swap( i, j );
+    }
+    return m_data[( i * m_n + j - ( i + 1 ) * ( i + 2 ) / 2 )];
+}
+
+
 template< typename T >
 inline T& WMatrixSymImpl< T >::operator()( size_t i, size_t j ) throw( WOutOfBounds )
 {
@@ -139,6 +165,37 @@ inline T& WMatrixSymImpl< T >::operator()( size_t i, size_t j ) throw( WOutOfBou
     return m_data[( i * m_n + j - ( i + 1 ) * ( i + 2 ) / 2 )];
 }
 
+template< typename T >
+inline std::string WMatrixSymImpl< T >::toString( void ) const
+{
+    std::stringstream ss;
+    ss.precision( 3 );
+    ss << std::fixed;
+    for( size_t i = 0; i < m_n; ++i )
+    {
+        for( size_t j = 0; j < m_n; ++j )
+        {
+            if( i != j )
+            {
+                ss << this->operator()(i,j);
+            }
+            else
+            {
+                ss << "0.0";
+            }
+            if( ( j + 1 ) < m_n )
+            {
+                ss << " ";
+            }
+        }
+        if( ( i + 1 ) < m_n )
+        {
+            ss << std::endl;
+        }
+    }
+    return ss.str();
+}
+
 template< typename T >
 inline size_t WMatrixSymImpl< T >::numElements() const
 {

src/core/common/math/test/WMatrixSym_test.h

@@ -81,11 +81,19 @@ public:
     void testInvalidAccessOnMainDiagonal( void )
     {
         WMatrixSymDBL t( 4 );
-        double mydata[] = { 1.6, 0.2, 7.7 }; // NOLINT
-        std::vector< double > data( mydata, mydata + sizeof( mydata ) / sizeof( double ) );
         TS_ASSERT_THROWS_EQUALS( t( 0, 0 ), WOutOfBounds &e, std::string( e.what() ),
                 "Invalid Element Access ( 0, 0 ). No diagonal elements or indices bigger than 4 are allowed." );
     }
+
+    void testToString( void )
+    {
+        WMatrixSymDBL t( 3 );
+        double mydata[] = { 1.6, 0.2, 1/3.0 }; // NOLINT
+        std::vector< double > data( mydata, mydata + sizeof( mydata ) / sizeof( double ) );
+        t.setData( data );
+        std::string expected = "0.0 1.600 0.200\n1.600 0.0 0.333\n0.200 0.333 0.0";
+        TS_ASSERT_EQUALS( expected, t.toString() );
+    }
 };
 
 #endif  // WMATRIXSYM_TEST_H