Fix bug #685: document the range of Random and setRandom

Eigen/src/Core/Random.h

@@ -27,6 +27,9 @@ struct functor_traits<scalar_random_op<Scalar> >
 } // end namespace internal
 
 /** \returns a random matrix expression
+  *
+  * Numbers are uniformly spread through their whole definition range for integer types,
+  * and in the [-1:1] range for floating point scalar types.
   * 
   * The parameters \a rows and \a cols are the number of rows and of columns of
   * the returned matrix. Must be compatible with this MatrixBase type.
@@ -35,6 +38,7 @@ struct functor_traits<scalar_random_op<Scalar> >
   * it is redundant to pass \a rows and \a cols as arguments, so Random() should be used
   * instead.
   * 
+  *
   * Example: \include MatrixBase_random_int_int.cpp
   * Output: \verbinclude MatrixBase_random_int_int.out
   *
@@ -52,6 +56,9 @@ DenseBase<Derived>::Random(Index rows, Index cols)
 }
 
 /** \returns a random vector expression
+  *
+  * Numbers are uniformly spread through their whole definition range for integer types,
+  * and in the [-1:1] range for floating point scalar types.
   *
   * The parameter \a size is the size of the returned vector.
   * Must be compatible with this MatrixBase type.
@@ -79,6 +86,9 @@ DenseBase<Derived>::Random(Index size)
 }
 
 /** \returns a fixed-size random matrix or vector expression
+  *
+  * Numbers are uniformly spread through their whole definition range for integer types,
+  * and in the [-1:1] range for floating point scalar types.
   * 
   * This variant is only for fixed-size MatrixBase types. For dynamic-size types, you
   * need to use the variants taking size arguments.
@@ -100,6 +110,9 @@ DenseBase<Derived>::Random()
 }
 
 /** Sets all coefficients in this expression to random values.
+  *
+  * Numbers are uniformly spread through their whole definition range for integer types,
+  * and in the [-1:1] range for floating point scalar types.
   * 
   * Example: \include MatrixBase_setRandom.cpp
   * Output: \verbinclude MatrixBase_setRandom.out
@@ -113,6 +126,9 @@ inline Derived& DenseBase<Derived>::setRandom()
 }
 
 /** Resizes to the given \a newSize, and sets all coefficients in this expression to random values.
+  *
+  * Numbers are uniformly spread through their whole definition range for integer types,
+  * and in the [-1:1] range for floating point scalar types.
   * 
   * \only_for_vectors
   *
@@ -130,6 +146,9 @@ PlainObjectBase<Derived>::setRandom(Index newSize)
 }
 
 /** Resizes to the given size, and sets all coefficients in this expression to random values.
+  *
+  * Numbers are uniformly spread through their whole definition range for integer types,
+  * and in the [-1:1] range for floating point scalar types.
   *
   * \param nbRows the new number of rows
   * \param nbCols the new number of columns