Added some missing comments and asserts.

--HG--
extra : convert_revision : svn%3Afdd8eb12-d10e-0410-9acb-85c331704f74/trunk%402854

dlib/matrix/matrix_la.h

@@ -1515,6 +1515,10 @@ convergence:
         const matrix_exp<EXP>& m
     )
     {
+        // You can only use this function with matrices that contain float or double values
+        COMPILE_TIME_ASSERT((is_same_type<typename EXP::type, float>::value ||
+                             is_same_type<typename EXP::type, double>::value));
+
         DLIB_ASSERT(m.nr() == m.nc(), 
             "\tconst matrix real_eigenvalues()"
             << "\n\tYou have given an invalidly sized matrix"

dlib/matrix/matrix_la_abstract.h

@@ -132,6 +132,7 @@ namespace dlib
     /*!
         requires
             - m.nr() == m.nc()
+            - matrix_exp::type == float or double
         ensures
             - returns a matrix E such that:
                 - E.nr() == m.nr()
@@ -216,6 +217,7 @@ namespace dlib
             REQUIREMENTS ON matrix_exp_type
                 must be some kind of matrix expression as defined in the 
                 dlib/matrix/matrix_abstract.h file.   (e.g. a dlib::matrix object)
+                The matrix type must also contain float or double values.
 
             WHAT THIS OBJECT REPRESENTS
                 This object represents something that can compute an LU 
@@ -361,6 +363,7 @@ namespace dlib
             REQUIREMENTS ON matrix_exp_type
                 must be some kind of matrix expression as defined in the 
                 dlib/matrix/matrix_abstract.h file.   (e.g. a dlib::matrix object)
+                The matrix type must also contain float or double values.
 
             WHAT THIS OBJECT REPRESENTS
                 This object represents something that can compute a cholesky 
@@ -453,6 +456,7 @@ namespace dlib
             REQUIREMENTS ON matrix_exp_type
                 must be some kind of matrix expression as defined in the 
                 dlib/matrix/matrix_abstract.h file.   (e.g. a dlib::matrix object)
+                The matrix type must also contain float or double values.
 
             WHAT THIS OBJECT REPRESENTS
                 This object represents something that can compute a classical
@@ -589,6 +593,7 @@ namespace dlib
             REQUIREMENTS ON matrix_exp_type
                 must be some kind of matrix expression as defined in the 
                 dlib/matrix/matrix_abstract.h file.   (e.g. a dlib::matrix object)
+                The matrix type must also contain float or double values.
 
             WHAT THIS OBJECT REPRESENTS
                 This object represents something that can compute an eigenvalue