<?xml version="1.0" encoding="ISO-8859-1"?>
<?xml-stylesheet type="text/xsl" href="stylesheet.xsl"?>

<doc>
   <title>Linear Algebra</title>

   <!-- ************************************************************************* -->

   <body>
         <br/><br/>
         <p>
            This page documents the core linear algebra tools included in dlib.
            In particular, the three most important objects in this part of the library are the
            <a href="#matrix">matrix</a>, <a href="#vector">vector</a>, and 
            <a href="#rectangle">rectangle</a>.  All the other tools on this page
            are functions for manipulating these three objects.  A good example and introduction 
            can be found in
            the <a href="matrix_ex.cpp.html">matrix example program</a>.
         </p>

         <p>
            Most of the linear algebra tools deal with dense matrices.  However, there is also
            a limited amount of support for working with sparse matrices and vectors.
            In particular, the dlib tools represent sparse vectors using the container objects
            in the C++ STL.  For details, see the notes at the top of 
            <a href="dlib/svm/sparse_vector_abstract.h.html#sparse_vectors">dlib/svm/sparse_vector_abstract.h</a>.
         </p>
         <p>
            Finally, note that all the dense matrix tools can be obtained by #including <tt>&lt;dlib/matrix.h&gt;</tt>
            while the sparse vector tools can be obtained by #including <tt>&lt;dlib/sparse_vector.h&gt;</tt>.  The 
            geometry tools can be used by #including <tt>&lt;dlib/geometry.h&gt;</tt>.
         </p>
   
   </body>

   <!-- ************************************************************************* -->

   <menu width="150">
    <top>

      <section>
         <name>Dense Matrix Tools</name>
         <item>matrix</item>
         <item nolink="true">
            <name>Basic_Math_Operators</name>
            <sub>
               <item>
                  <name>exp</name>
                  <link>dlib/matrix/matrix_math_functions_abstract.h.html#exp</link>
               </item>
               <item>
                  <name>log10</name>
                  <link>dlib/matrix/matrix_math_functions_abstract.h.html#log10</link>
               </item>
               <item>
                  <name>log</name>
                  <link>dlib/matrix/matrix_math_functions_abstract.h.html#log</link>
               </item>
               <item>
                  <name>sqrt</name>
                  <link>dlib/matrix/matrix_math_functions_abstract.h.html#sqrt</link>
               </item>
               <item>
                  <name>pow</name>
                  <link>dlib/matrix/matrix_math_functions_abstract.h.html#pow</link>
               </item>
               <item>
                  <name>squared</name>
                  <link>dlib/matrix/matrix_math_functions_abstract.h.html#squared</link>
               </item>
               <item>
                  <name>cubed</name>
                  <link>dlib/matrix/matrix_math_functions_abstract.h.html#cubed</link>
               </item>
               <item>
                  <name>sigmoid</name>
                  <link>dlib/matrix/matrix_math_functions_abstract.h.html#sigmoid</link>
               </item>
               <item>
                  <name>abs</name>
                  <link>dlib/matrix/matrix_math_functions_abstract.h.html#abs</link>
               </item>
               <item>
                  <name>reciprocal</name>
                  <link>dlib/matrix/matrix_math_functions_abstract.h.html#reciprocal</link>
               </item>
               <item>
                  <name>reciprocal_max</name>
                  <link>dlib/matrix/matrix_math_functions_abstract.h.html#reciprocal_max</link>
               </item>
               <item>
                  <name>normalize</name>
                  <link>dlib/matrix/matrix_math_functions_abstract.h.html#normalize</link>
               </item>
               <item>
                  <name>round</name>
                  <link>dlib/matrix/matrix_math_functions_abstract.h.html#round</link>
               </item>
               <item>
                  <name>ceil</name>
                  <link>dlib/matrix/matrix_math_functions_abstract.h.html#ceil</link>
               </item>
               <item>
                  <name>floor</name>
                  <link>dlib/matrix/matrix_math_functions_abstract.h.html#floor</link>
               </item>
               <item>
                  <name>round_zeros</name>
                  <link>dlib/matrix/matrix_math_functions_abstract.h.html#round_zeros</link>
               </item>
               <item>
                  <name>conj</name>
                  <link>dlib/matrix/matrix_math_functions_abstract.h.html#conj</link>
               </item>
               <item>
                  <name>norm</name>
                  <link>dlib/matrix/matrix_math_functions_abstract.h.html#norm</link>
               </item>
               <item>
                  <name>imag</name>
                  <link>dlib/matrix/matrix_math_functions_abstract.h.html#imag</link>
               </item>
               <item>
                  <name>real</name>
                  <link>dlib/matrix/matrix_math_functions_abstract.h.html#real</link>
               </item>
               <item>
                  <name>complex_matrix</name>
                  <link>dlib/matrix/matrix_math_functions_abstract.h.html#complex_matrix</link>
               </item>
               <item>
                  <name>sin</name>
                  <link>dlib/matrix/matrix_math_functions_abstract.h.html#sin</link>
               </item>
               <item>
                  <name>cos</name>
                  <link>dlib/matrix/matrix_math_functions_abstract.h.html#cos</link>
               </item>
               <item>
                  <name>tan</name>
                  <link>dlib/matrix/matrix_math_functions_abstract.h.html#tan</link>
               </item>
               <item>
                  <name>asin</name>
                  <link>dlib/matrix/matrix_math_functions_abstract.h.html#asin</link>
               </item>
               <item>
                  <name>acos</name>
                  <link>dlib/matrix/matrix_math_functions_abstract.h.html#acos</link>
               </item>
               <item>
                  <name>atan</name>
                  <link>dlib/matrix/matrix_math_functions_abstract.h.html#atan</link>
               </item>
               <item>
                  <name>sinh</name>
                  <link>dlib/matrix/matrix_math_functions_abstract.h.html#sinh</link>
               </item>
               <item>
                  <name>cosh</name>
                  <link>dlib/matrix/matrix_math_functions_abstract.h.html#cosh</link>
               </item>
               <item>
                  <name>tanh</name>
                  <link>dlib/matrix/matrix_math_functions_abstract.h.html#tanh</link>
               </item>
            </sub>
         </item>
         <item nolink="true">
            <name>Linear_Algebra</name>
            <sub>
               <item>
                  <name>inv</name>
                  <link>dlib/matrix/matrix_la_abstract.h.html#inv</link>
               </item>
               <item>
                  <name>pinv</name>
                  <link>dlib/matrix/matrix_la_abstract.h.html#pinv</link>
               </item>
               <item>
                  <name>svd</name>
                  <link>dlib/matrix/matrix_la_abstract.h.html#svd</link>
               </item>
               <item>
                  <name>svd2</name>
                  <link>dlib/matrix/matrix_la_abstract.h.html#svd2</link>
               </item>
               <item>
                  <name>svd3</name>
                  <link>dlib/matrix/matrix_la_abstract.h.html#svd3</link>
               </item>
               <item>
                  <name>det</name>
                  <link>dlib/matrix/matrix_la_abstract.h.html#det</link>
               </item>
               <item>
                  <name>trace</name>
                  <link>dlib/matrix/matrix_la_abstract.h.html#trace</link>
               </item>
               <item>
                  <name>dot</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#dot</link>
               </item>
               <item>
                  <name>length</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#length</link>
               </item>
               <item>
                  <name>length_squared</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#length_squared</link>
               </item>
               <item>
                  <name>trans</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#trans</link>
               </item>
               <item>
                  <name>diag</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#diag</link>
               </item>
               <item>
                  <name>diagm</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#diagm</link>
               </item>
               <item>
                  <name>lowerm</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#lowerm</link>
               </item>
               <item>
                  <name>upperm</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#upperm</link>
               </item>
               <item>
                  <name>chol</name>
                  <link>dlib/matrix/matrix_la_abstract.h.html#chol</link>
               </item>
               <item>
                  <name>inv_lower_triangular</name>
                  <link>dlib/matrix/matrix_la_abstract.h.html#inv_lower_triangular</link>
               </item>
               <item>
                  <name>inv_upper_triangular</name>
                  <link>dlib/matrix/matrix_la_abstract.h.html#inv_upper_triangular</link>
               </item>
               <item>
                  <name>lu_decomposition</name>
                  <link>dlib/matrix/matrix_la_abstract.h.html#lu_decomposition</link>
               </item>
               <item>
                  <name>qr_decomposition</name>
                  <link>dlib/matrix/matrix_la_abstract.h.html#qr_decomposition</link>
               </item>
               <item>
                  <name>cholesky_decomposition</name>
                  <link>dlib/matrix/matrix_la_abstract.h.html#cholesky_decomposition</link>
               </item>
               <item>
                  <name>eigenvalue_decomposition</name>
                  <link>dlib/matrix/matrix_la_abstract.h.html#eigenvalue_decomposition</link>
               </item>
               <item>
                  <name>real_eigenvalues</name>
                  <link>dlib/matrix/matrix_la_abstract.h.html#real_eigenvalues</link>
               </item>
            </sub>
         </item>
         <item nolink="true">
            <name>Conversions</name>
            <sub>
               <item>mat</item>
               <item>
                  <name>matrix_cast</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#matrix_cast</link>
               </item>
               <item>
                  <name>pixel_to_vector</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#pixel_to_vector</link>
               </item>
               <item>
                  <name>vector_to_pixel</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#vector_to_pixel</link>
               </item>
            </sub>
         </item>
         <item nolink="true">
            <name>Sub_Matrix_Expressions</name>
            <sub>
               <item>
                  <name>range</name>
                  <link>dlib/matrix/matrix_subexp_abstract.h.html#range</link>
               </item>
               <item>
                  <name>subm</name>
                  <link>dlib/matrix/matrix_subexp_abstract.h.html#subm</link>
               </item>
               <item>
                  <name>rowm</name>
                  <link>dlib/matrix/matrix_subexp_abstract.h.html#rowm</link>
               </item>
               <item>
                  <name>colm</name>
                  <link>dlib/matrix/matrix_subexp_abstract.h.html#colm</link>
               </item>
               <item>
                  <name>set_subm</name>
                  <link>dlib/matrix/matrix_subexp_abstract.h.html#set_subm</link>
               </item>
               <item>
                  <name>set_colm</name>
                  <link>dlib/matrix/matrix_subexp_abstract.h.html#set_colm</link>
               </item>
               <item>
                  <name>set_rowm</name>
                  <link>dlib/matrix/matrix_subexp_abstract.h.html#set_rowm</link>
               </item>
            </sub>
         </item>
         <item nolink="true">
            <name>Statistics</name>
            <sub>
               <item>
                  <name>sum</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#sum</link>
               </item>
               <item>
                  <name>sum_rows</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#sum_rows</link>
               </item>
               <item>
                  <name>sum_cols</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#sum_cols</link>
               </item>
               <item>
                  <name>prod</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#prod</link>
               </item>
               <item>
                  <name>mean</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#mean</link>
               </item>
               <item>
                  <name>max</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#max</link>
               </item>
               <item>
                  <name>min</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#min</link>
               </item>
               <item>
                  <name>find_min_and_max</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#find_min_and_max</link>
               </item>
               <item>
                  <name>index_of_min</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#index_of_min</link>
               </item>
               <item>
                  <name>index_of_max</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#index_of_max</link>
               </item>
               <item>
                  <name>variance</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#variance</link>
               </item>
               <item>
                  <name>stddev</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#stddev</link>
               </item>
               <item>
                  <name>covariance</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#covariance</link>
               </item>
               <item>
                  <name>randm</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#randm</link>
               </item>
               <item>
                  <name>gaussian_randm</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#gaussian_randm</link>
               </item>
            </sub>
         </item>
         <item nolink="true">
            <name>Other_Utilities</name>
            <sub>
               <item>
                  <name>is_col_vector</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#is_col_vector</link>
               </item>
               <item>
                  <name>is_row_vector</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#is_row_vector</link>
               </item>
               <item>
                  <name>is_vector</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#is_vector</link>
               </item>
               <item>
                  <name>const_temp_matrix</name>
                  <link>dlib/matrix/matrix_abstract.h.html#const_temp_matrix</link>
               </item>
               <item>
                  <name>symmetric_matrix_cache</name>
                  <link>dlib/matrix/symmetric_matrix_cache_abstract.h.html</link>
               </item>
               <item>
                  <name>conv</name>
                  <link>dlib/matrix/matrix_conv_abstract.h.html#conv</link>
               </item>
               <item>
                  <name>conv_same</name>
                  <link>dlib/matrix/matrix_conv_abstract.h.html#conv_same</link>
               </item>
               <item>
                  <name>conv_valid</name>
                  <link>dlib/matrix/matrix_conv_abstract.h.html#conv_valid</link>
               </item>
               <item>
                  <name>xcorr</name>
                  <link>dlib/matrix/matrix_conv_abstract.h.html#xcorr</link>
               </item>
               <item>
                  <name>xcorr_same</name>
                  <link>dlib/matrix/matrix_conv_abstract.h.html#xcorr_same</link>
               </item>
               <item>
                  <name>xcorr_valid</name>
                  <link>dlib/matrix/matrix_conv_abstract.h.html#xcorr_valid</link>
               </item>
               <item>
                  <name>flip</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#flip</link>
               </item>
               <item>
                  <name>flipud</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#flipud</link>
               </item>
               <item>
                  <name>fliplr</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#fliplr</link>
               </item>
               <item>
                  <name>make_symmetric</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#make_symmetric</link>
               </item>
               <item>
                  <name>ones_matrix</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#ones_matrix</link>
               </item>
               <item>
                  <name>zeros_matrix</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#zeros_matrix</link>
               </item>
               <item>
                  <name>uniform_matrix</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#uniform_matrix</link>
               </item>
               <item>
                  <name>identity_matrix</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#identity_matrix</link>
               </item>
               <item>
                  <name>rotate</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#rotate</link>
               </item>
               <item>
                  <name>reshape_to_column_vector</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#reshape_to_column_vector</link>
               </item>
               <item>
                  <name>reshape</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#reshape</link>
               </item>
               <item>
                  <name>removerc</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#removerc</link>
               </item>
               <item>
                  <name>remove_row</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#remove_row</link>
               </item>
               <item>
                  <name>remove_col</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#remove_col</link>
               </item>
               <item>
                  <name>set_all_elements</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#set_all_elements</link>
               </item>
               <item>
                  <name>hash</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#hash</link>
               </item>
               <item>
                  <name>tmp</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#tmp</link>
               </item>
               <item>
                  <name>equal</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#equal</link>
               </item>
               <item>
                  <name>pointwise_multiply</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#pointwise_multiply</link>
               </item>
               <item>
                  <name>join_rows</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#join_rows</link>
               </item>
               <item>
                  <name>join_cols</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#join_cols</link>
               </item>
               <item>
                  <name>tensor_product</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#tensor_product</link>
               </item>
               <item>
                  <name>scale_columns</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#scale_columns</link>
               </item>
               <item>
                  <name>scale_rows</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#scale_rows</link>
               </item>
               <item>
                  <name>sort_columns</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#sort_columns</link>
               </item>
               <item>
                  <name>rsort_columns</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#rsort_columns</link>
               </item>

               <item>
                  <name>clamp</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#clamp</link>
               </item>
               <item>
                  <name>lowerbound</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#lowerbound</link>
               </item>
               <item>
                  <name>upperbound</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#upperbound</link>
               </item>
               <item>
                  <name>linspace</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#linspace</link>
               </item>
               <item>
                  <name>logspace</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#logspace</link>
               </item>
               <item>
                  <name>cartesian_product</name>
                  <link>dlib/matrix/matrix_utilities_abstract.h.html#cartesian_product</link>
               </item>
            </sub>
         </item>
      </section>

      <section>
         <name>2D/3D Geometry</name>
         <item>border_enumerator</item> 
         <item>rectangle</item> 
         <item>vector</item> 
         <item>point</item> 
         <item>rotate_point</item> 
         <item>point_rotator</item> 
         <item>point_transform</item> 
         <item>point_transform_affine</item> 
         <item>find_affine_transform</item> 
         <item>rotation_matrix</item> 
         <item>get_rect</item> 
         <item>centered_rect</item> 
         <item>center</item> 
         <item>dcenter</item> 
         <item>shrink_rect</item> 
         <item>grow_rect</item> 
         <item>translate_rect</item> 
         <item>resize_rect</item> 
         <item>resize_rect_width</item> 
         <item>resize_rect_height</item> 
         <item>move_rect</item> 
         <item>nearest_point</item> 
         <item>distance_to_rect_edge</item> 
      </section>


      <section>
         <name>Sparse Vector Tools</name>
         <item>sparse_to_dense</item> 

         <item>
            <name>distance_squared</name>
            <link>dlib/svm/sparse_vector_abstract.h.html#distance_squared</link>
         </item> 
         <item>
            <name>distance</name>
            <link>dlib/svm/sparse_vector_abstract.h.html#distance</link>
         </item> 
         <item>
            <name>assign</name>
            <link>dlib/svm/sparse_vector_abstract.h.html#assign</link>
         </item> 
         <item>
            <name>length_squared</name>
            <link>dlib/svm/sparse_vector_abstract.h.html#length_squared</link>
         </item> 
         <item>
            <name>length</name>
            <link>dlib/svm/sparse_vector_abstract.h.html#length</link>
         </item> 
         <item>
            <name>scale_by</name>
            <link>dlib/svm/sparse_vector_abstract.h.html#scale_by</link>
         </item> 
         <item>
            <name>add</name>
            <link>dlib/svm/sparse_vector_abstract.h.html#add</link>
         </item> 
         <item>
            <name>subtract</name>
            <link>dlib/svm/sparse_vector_abstract.h.html#subtract</link>
         </item> 
         <item>
            <name>max_index_plus_one</name>
            <link>dlib/svm/sparse_vector_abstract.h.html#max_index_plus_one</link>
         </item> 
         <item>
            <name>add_to</name>
            <link>dlib/svm/sparse_vector_abstract.h.html#add_to</link>
         </item> 
         <item>
            <name>subtract_from</name>
            <link>dlib/svm/sparse_vector_abstract.h.html#subtract_from</link>
         </item> 
         <item>
            <name>min</name>
            <link>dlib/svm/sparse_vector_abstract.h.html#min</link>
         </item> 
         <item>
            <name>max</name>
            <link>dlib/svm/sparse_vector_abstract.h.html#max</link>
         </item> 
         <item>
            <name>make_sparse_vector</name>
            <link>dlib/svm/sparse_vector_abstract.h.html#make_sparse_vector</link>
         </item> 
         <item>
            <name>sparse_matrix_vector_multiply</name>
            <link>dlib/svm/sparse_vector_abstract.h.html#sparse_matrix_vector_multiply</link>
         </item> 
      </section>

    </top>
   </menu>

   <!-- ************************************************************************* -->
   <!-- ************************************************************************* -->
   <!-- ************************************************************************* -->

   <components>
   
   <!-- ************************************************************************* -->

      <component>
         <name>sparse_to_dense</name>
         <file>dlib/sparse_vector.h</file>
         <spec_file link="true">dlib/svm/sparse_vector_abstract.h</spec_file>
         <description>
            This is a set of simple functions that take  
            <a href="dlib/svm/sparse_vector_abstract.h.html#sparse_vectors">sparse vectors</a> 
            and converts them into equivalent dense vectors.  
         </description>
      </component>
      
   <!-- ************************************************************************* -->

      <component>
         <name>mat</name>
         <file>dlib/matrix.h</file>
         <spec_file link="true">dlib/matrix/matrix_mat_abstract.h</spec_file>
         <description>
            This is a set of simple functions that take objects like std::vector or
            <a href="containers.html#array2d">array2d</a> and convert them into 
            <a href="#matrix">matrix</a> objects.  Note that the conversion is 
            done using template expressions so there is no runtime cost associated
            with calling mat().
         </description>
      </component>
      

   <!-- ************************************************************************* -->
      
      <component>
         <name>matrix</name>
         <file>dlib/matrix.h</file>
         <spec_file link="true">dlib/matrix/matrix_abstract.h</spec_file>
         <description>
           This is a 2D matrix object that enables you to write code that deals with
           matrices using a simple syntax similar to what can be written in MATLAB.  It is implemented using 
           the <a href="matrix_expressions_ex.cpp.html">expression templates</a> technique which allows it to eliminate the 
           temporary matrix objects that would normally be returned from expressions 
           such as M = A+B+C+D;  Normally each invocation of the + operator would 
           construct and return a temporary matrix object but using this technique 
           we can avoid creating all these temporary objects and receive a large speed boost.
           <p>
           This object is also capable of using BLAS and LAPACK libraries such as ATLAS or the Intel
           MKL when available.   To enable BLAS support all you have to do is #define 
           DLIB_USE_BLAS and then make sure you link your application with your 
           BLAS library.  Similarly, to enable LAPACK support just #define DLIB_USE_LAPACK and 
           link to your LAPACK library.  Finally, the use of BLAS and LAPACK is transparent to 
           the user, that is, the dlib matrix object uses BLAS and LAPACK internally to optimize 
           various operations while still allowing the user to use a simple MATLAB like syntax.  
           </p>
           <p>
           Note that the cmake files that come with dlib know how to link a project with ATLAS or
           the Intel MKL if you are building on a linux system.  The cmake files may also 
           work in a few other cases as well but I haven't tested any others.   But in any
           case, by no means are you required to use the dlib cmake files. 
           </p>
           <p>
              It is also worth noting that all the preconditions of every function 
              related to the matrix object are checked by <a href="metaprogramming.html#DLIB_ASSERT">DLIB_ASSERT</a>
              statements and thus can be enabled by #defining ENABLE_ASSERTS or DEBUG.  Doing
              this will cause your program to run slower but should catch any usage errors. 
           </p>
         </description>
         
         <examples>
            <example>matrix_ex.cpp.html</example>
            <example>matrix_expressions_ex.cpp.html</example>
         </examples>

         <extensions>
            <extension>
               <name>matrix_utilities</name>
               <spec_file>dlib/matrix/matrix_utilities_abstract.h</spec_file>
               <description>
                  This extension contains miscellaneous utility functions
                  for manipulating matrix objects.  
               </description>
            </extension>

            <extension>
               <name>matrix_la</name>
               <spec_file>dlib/matrix/matrix_la_abstract.h</spec_file>
               <description>
                  This extension contains linear algebra functions to calculate 
                  QR, LU, Cholesky, eigenvalue, and singular value decompositions.  It also
                  contains a few other miscellaneous functions that solve systems of 
                  equations or calculate values derived from the above decompositions.
               </description>
            </extension>

            <extension>
               <name>matrix_math_functions</name>
               <spec_file>dlib/matrix/matrix_math_functions_abstract.h</spec_file>
               <description>This extension contains mathematical functions that operate on each
                  element of a matrix independently.  
               </description>
            </extension>

            <extension>
               <name>matrix_sub_expressions</name>
               <spec_file>dlib/matrix/matrix_subexp_abstract.h</spec_file>
               <description>
                  This extension contains a number of functions for dealing with sub-matrices.  
               </description>
            </extension>
         </extensions>              
                                    
      </component>
      
   <!-- ************************************************************************* -->

      <component>
         <name>border_enumerator</name>
         <file>dlib/geometry.h</file>
         <spec_file>dlib/geometry/border_enumerator_abstract.h</spec_file>
         <description>
            This object is an <a href="containers.html#enumerable">enumerator</a> 
            over the border <a href="#point">points</a> of a 
            <a href="#rectangle">rectangle</a>.
         </description>
      </component>
            
   <!-- ************************************************************************* -->

      <component>
         <name>nearest_point</name>
         <file>dlib/geometry.h</file>
         <spec_file link="true">dlib/geometry/rectangle_abstract.h</spec_file>
         <description>        
            This function takes a <a href="#rectangle">rectangle</a> and a 
            <a href="#point">point</a> and returns the point in the given 
            rectangle that is nearest to the given point.
         </description>
                                 
      </component>

   <!-- ************************************************************************* -->

      <component>
         <name>distance_to_rect_edge</name>
         <file>dlib/geometry.h</file>
         <spec_file link="true">dlib/geometry/rectangle_abstract.h</spec_file>
         <description>        
            This function takes a <a href="#rectangle">rectangle</a> and a 
            <a href="#point">point</a> and returns the Manhattan distance between
            the rectangle's edge and the point.
         </description>
                                 
      </component>

   <!-- ************************************************************************* -->

      <component>
         <name>move_rect</name>
         <file>dlib/geometry.h</file>
         <spec_file link="true">dlib/geometry/rectangle_abstract.h</spec_file>
         <description>        
            This function takes a <a href="#rectangle">rectangle</a> and moves
            it so that it's upper left corner occupies the given location.
         </description>
                                 
      </component>

   <!-- ************************************************************************* -->

      <component>
         <name>resize_rect_height</name>
         <file>dlib/geometry.h</file>
         <spec_file link="true">dlib/geometry/rectangle_abstract.h</spec_file>
         <description>        
            This function takes a <a href="#rectangle">rectangle</a> and 
            returns a new rectangle with the given height but otherwise with the 
            same edge points as the original rectangle. 
         </description>
                                 
      </component>

   <!-- ************************************************************************* -->

      <component>
         <name>resize_rect_width</name>
         <file>dlib/geometry.h</file>
         <spec_file link="true">dlib/geometry/rectangle_abstract.h</spec_file>
         <description>        
            This function takes a <a href="#rectangle">rectangle</a> and 
            returns a new rectangle with the given width but otherwise with the 
            same edge points as the original rectangle. 
         </description>
                                 
      </component>

   <!-- ************************************************************************* -->

      <component>
         <name>resize_rect</name>
         <file>dlib/geometry.h</file>
         <spec_file link="true">dlib/geometry/rectangle_abstract.h</spec_file>
         <description>        
            This function takes a <a href="#rectangle">rectangle</a> and 
            returns a new rectangle with the given size but with the same upper
            left corner as the original rectangle.
         </description>
                                 
      </component>

   <!-- ************************************************************************* -->

      <component>
         <name>translate_rect</name>
         <file>dlib/geometry.h</file>
         <spec_file link="true">dlib/geometry/rectangle_abstract.h</spec_file>
         <description>        
            This function takes a <a href="#rectangle">rectangle</a> and moves
            it by a given number of units along the x and y axis relative to
            where it was before the move.
         </description>
                                 
      </component>

   <!-- ************************************************************************* -->

      <component>
         <name>center</name>
         <file>dlib/geometry.h</file>
         <spec_file link="true">dlib/geometry/rectangle_abstract.h</spec_file>
         <description>        
            Returns the center point of a <a href="#rectangle">rectangle</a>.
         </description>
                                 
      </component>

   <!-- ************************************************************************* -->

      <component>
         <name>dcenter</name>
         <file>dlib/geometry.h</file>
         <spec_file link="true">dlib/geometry/rectangle_abstract.h</spec_file>
         <description>        
            Returns the center point of a <a href="#rectangle">rectangle</a>.  This
            is a version of <a href="#center">center()</a> which returns a double version 
            of the point rather than one which uses integers to represent the 
            result.  Therefore, it is slightly more accurate.
         </description>
                                 
      </component>

   <!-- ************************************************************************* -->

      <component>
         <name>centered_rect</name>
         <file>dlib/geometry.h</file>
         <spec_file link="true">dlib/geometry/rectangle_abstract.h</spec_file>
         <description>        
            There are various overloads of this function but the basic idea is
            that it returns a <a href="#rectangle">rectangle</a> with a given 
            width and height and centered about a given point.
         </description>
                                 
      </component>

   <!-- ************************************************************************* -->

      <component>
         <name>shrink_rect</name>
         <file>dlib/geometry.h</file>
         <spec_file link="true">dlib/geometry/rectangle_abstract.h</spec_file>
         <description>        
            This function takes a <a href="#rectangle">rectangle</a> object, 
            shrinks its borders by a given amount, and returns the result.
         </description>
                                 
      </component>

   <!-- ************************************************************************* -->

      <component>
         <name>grow_rect</name>
         <file>dlib/geometry.h</file>
         <spec_file link="true">dlib/geometry/rectangle_abstract.h</spec_file>
         <description>        
            This function takes a <a href="#rectangle">rectangle</a> object, 
            grows its borders by a given amount, and returns the result.
         </description>
                                 
      </component>

   <!-- ************************************************************************* -->

      <component>
         <name>rotate_point</name>
         <file>dlib/geometry.h</file>
         <spec_file link="true">dlib/geometry/point_transforms_abstract.h</spec_file>
         <description>        
            This is a function that rotates a 2D <a href="#vector">vector</a> or 
            <a href="#point">point</a> object about a given point.
         </description>
                                 
      </component>

   <!-- ************************************************************************* -->

      <component>
         <name>point_rotator</name>
         <file>dlib/geometry.h</file>
         <spec_file link="true">dlib/geometry/point_transforms_abstract.h</spec_file>
         <description>        
            This is an object that rotates a 2D <a href="#vector">vector</a> or 
            <a href="#point">point</a> object about the origin.
         </description>
                                 
      </component>

   <!-- ************************************************************************* -->

      <component>
         <name>point_transform</name>
         <file>dlib/geometry.h</file>
         <spec_file link="true">dlib/geometry/point_transforms_abstract.h</spec_file>
         <description>        
            This is an object that rotates a 2D <a href="#vector">vector</a> or 
            <a href="#point">point</a> object about the origin and then adds a 
            displacement vector.
         </description>
                                 
      </component>

   <!-- ************************************************************************* -->

      <component>
         <name>point_transform_affine</name>
         <file>dlib/geometry.h</file>
         <spec_file link="true">dlib/geometry/point_transforms_abstract.h</spec_file>
         <description>        
            This is an object that applies an affine transformation to a <a href="#vector">vector</a> or 
            <a href="#point">point</a>.  Note that you can use <a href="#find_affine_transform">find_affine_transform</a>
            to easily create affine transforms from sets of point correspondences.
         </description>
                                 
      </component>

   <!-- ************************************************************************* -->

      <component>
         <name>find_affine_transform</name>
         <file>dlib/geometry.h</file>
         <spec_file link="true">dlib/geometry/point_transforms_abstract.h</spec_file>
         <description>        
            This is a routine that takes in two sets of points and finds the
            best <a href="#point_transform_affine">affine transformation</a>
            that maps between them.
         </description>
                                 
      </component>

   <!-- ************************************************************************* -->

      <component>
         <name>rotation_matrix</name>
         <file>dlib/geometry.h</file>
         <spec_file link="true">dlib/geometry/point_transforms_abstract.h</spec_file>
         <description>        
            This is a method for creating 2D rotation matrices.
         </description>
                                 
      </component>

   <!-- ************************************************************************* -->

      <component>
         <name>get_rect</name>
         <file>dlib/geometry.h</file>
         <spec_file link="true">dlib/geometry/rectangle_abstract.h</spec_file>
         <description>        
            This is a simple template function that returns a rectangle 
            representing the size of a 2D container (e.g. <a href="containers.html#matrix">matrix</a> or
            <a href="containers.html#array2d">array2d</a>). 
         </description>
      </component>

   <!-- ************************************************************************* -->

      <component>
         <name>rectangle</name>
         <file>dlib/geometry.h</file>
         <spec_file>dlib/geometry/rectangle_abstract.h</spec_file>
         <description>
            This object represents a rectangular region inside a Cartesian 
            coordinate system.  It allows you to easily represent and manipulate
            rectangles.
         </description>
      </component>
            
   <!-- ************************************************************************* -->
      
      <component>
         <name>vector</name>
         <file>dlib/geometry.h</file>
         <spec_file link="true">dlib/geometry/vector_abstract.h</spec_file>
         <description>
            This object represents a two or three dimensional vector.  

            <p>If you
            want to work with general N-dimensional column vectors then you
            should the <a href="#matrix">matrix</a> object.  In particular, you
            should usually use a matrix with this type:
            <tt>dlib::matrix&lt;double,0,1&gt;</tt>.</p>
         </description>
      </component>
      
   <!-- ************************************************************************* -->
      
      <component>
         <name>point</name>
         <file>dlib/geometry.h</file>
         <spec_file link="true">dlib/geometry/vector_abstract.h</spec_file>
         <description>
               This object represents a point inside a Cartesian coordinate system.
               Note that a point is simply a typedef for a <a href="#vector">vector</a>
               that is 2D and uses longs to represent coordinate values.
         </description>
      </component>
      
   <!-- ************************************************************************* -->
      
      
   </components>

   <!-- ************************************************************************* -->


</doc>

