diff --git a/CMakeLists.txt b/CMakeLists.txt
index c942806..9f8be83 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -46,6 +46,7 @@ if(ROTGEN_FORCE_DYNAMIC)
         src/info.cpp
         src/svd.cpp
         src/operators.cpp
+        src/format.cpp
       )
 else()
   set ( SOURCES
diff --git a/include/rotgen/common/ref.hpp b/include/rotgen/common/ref.hpp
index ffde241..53503f3 100644
--- a/include/rotgen/common/ref.hpp
+++ b/include/rotgen/common/ref.hpp
@@ -112,7 +112,12 @@ namespace rotgen
 
     friend std::ostream& operator<<(std::ostream& os, ref const& r)
     {
-      return os << r.base() << "\n";
+      return os << r.base();
+    }
+
+    friend std::ostream& operator<<(std::ostream& os, format<ref> const& r)
+    {
+      return os << format{r.matrix_.base(),r.format_};
     }
   };
 
@@ -201,7 +206,12 @@ namespace rotgen
 
     friend std::ostream& operator<<(std::ostream& os, ref const& r)
     {
-      return os << r.base() << "\n";
+      return os << r.base();
+    }
+
+    friend std::ostream& operator<<(std::ostream& os, format<ref> const& r)
+    {
+      return os << format{r.matrix_.base(),r.format_};
     }
   };
 
diff --git a/include/rotgen/config.hpp b/include/rotgen/config.hpp
index 927990a..3b17439 100644
--- a/include/rotgen/config.hpp
+++ b/include/rotgen/config.hpp
@@ -41,6 +41,10 @@ namespace rotgen
   inline constexpr int Aligned64  = 64;
   inline constexpr int Aligned128 = 128;
   inline constexpr int Aligned    = default_alignment;
+
+  inline constexpr int DontAlignCols    =  1;
+  inline constexpr int StreamPrecision  = -1;
+  inline constexpr int FullPrecision    = -2;
 }
 
 namespace rotgen::detail
diff --git a/include/rotgen/dynamic/format.hpp b/include/rotgen/dynamic/format.hpp
new file mode 100644
index 0000000..02bfe0b
--- /dev/null
+++ b/include/rotgen/dynamic/format.hpp
@@ -0,0 +1,51 @@
+//==================================================================================================
+/*
+  ROTGEN - Runtime Overlay for Eigen
+  Copyright : CODE RECKONS
+  SPDX-License-Identifier: BSL-1.0
+*/
+//==================================================================================================
+#pragma once
+
+#include <rotgen/config.hpp>
+#include <memory>
+#include <string>
+
+namespace rotgen
+{
+  class ROTGEN_EXPORT ioformat
+  {
+    private:
+    struct payload;
+    std::unique_ptr<payload> storage_;
+
+    public:
+    ioformat( int precision, int flags = 0
+            , std::string const& coeffSeparator = " "
+            , std::string const& rowSeparator = "\n"
+            , std::string const& rowPrefix = "", std::string const& rowSuffix = ""
+            , std::string const& matPrefix = "", std::string const& matSuffix = ""
+            , char fill = ' '
+            );
+
+
+    ~ioformat();
+
+    std::unique_ptr<payload> const& storage() const { return storage_; }
+  };
+
+  template <typename M>
+  struct format
+  {
+    format(const M& m, const ioformat& f) : matrix_(m), format_(f) {}
+
+    M         const&  matrix_;
+    ioformat  const&  format_;
+  };
+
+  template <typename M>
+  std::ostream& operator<<(std::ostream& os, const format<M>& f)
+  {
+    return os << format{f.matrix_.base(), f.format_};
+  }
+}
diff --git a/include/rotgen/fixed/format.hpp b/include/rotgen/fixed/format.hpp
new file mode 100644
index 0000000..7c2ced5
--- /dev/null
+++ b/include/rotgen/fixed/format.hpp
@@ -0,0 +1,34 @@
+//==================================================================================================
+/*
+  ROTGEN - Runtime Overlay for Eigen
+  Copyright : CODE RECKONS
+  SPDX-License-Identifier: BSL-1.0
+*/
+//==================================================================================================
+#pragma once
+
+#include <rotgen/config.hpp>
+#include <rotgen/concepts.hpp>
+#include <memory>
+#include <string>
+
+namespace rotgen
+{
+  using ioformat = Eigen::IOFormat;
+
+  template <typename M>
+  struct format
+  {
+    format(const M& m, const ioformat& f) : matrix_(m), format_(f) {}
+
+    M         const&  matrix_;
+    ioformat  const&  format_;
+  };
+
+  template <typename M>
+  std::ostream& operator<<(std::ostream& os, const format<M>& f)
+  {
+    if constexpr(concepts::eigen_compatible<M>) return os << f.matrix_.format(f.format_);
+    else                                        return os << f.matrix_.base().format(f.format_);
+  }
+}
diff --git a/include/rotgen/impl/block_model.hpp b/include/rotgen/impl/block_model.hpp
index 7bd4abc..58eab26 100644
--- a/include/rotgen/impl/block_model.hpp
+++ b/include/rotgen/impl/block_model.hpp
@@ -96,6 +96,7 @@ class ROTGEN_EXPORT CLASSNAME
   SOURCENAME div(TYPE s) const;
 
   friend ROTGEN_EXPORT std::ostream& operator<<(std::ostream&,CLASSNAME const&);
+  friend ROTGEN_EXPORT std::ostream& operator<<(std::ostream&, format<CLASSNAME> const&);
   friend ROTGEN_EXPORT bool operator==(CLASSNAME const& lhs, CLASSNAME const& rhs);
   friend ROTGEN_EXPORT bool operator!=(CLASSNAME const& lhs, CLASSNAME const& rhs);
 
diff --git a/include/rotgen/impl/map_model.hpp b/include/rotgen/impl/map_model.hpp
index 41c4c8c..9f69792 100644
--- a/include/rotgen/impl/map_model.hpp
+++ b/include/rotgen/impl/map_model.hpp
@@ -106,7 +106,8 @@ class ROTGEN_EXPORT CLASSNAME
 
   SOURCENAME inverse() const;
 
-  friend ROTGEN_EXPORT std::ostream& operator<<(std::ostream&,CLASSNAME const&);
+  friend ROTGEN_EXPORT std::ostream& operator<<(std::ostream&, CLASSNAME const&);
+  friend ROTGEN_EXPORT std::ostream& operator<<(std::ostream&, format<CLASSNAME> const&);
   const TYPE* data() const;
 
   #if !defined(USE_CONST)
diff --git a/include/rotgen/impl/matrix.hpp b/include/rotgen/impl/matrix.hpp
index 5953439..dd1e5a8 100644
--- a/include/rotgen/impl/matrix.hpp
+++ b/include/rotgen/impl/matrix.hpp
@@ -8,6 +8,7 @@
 #pragma once
 
 #include <rotgen/detail/generators.hpp>
+#include <rotgen/dynamic/format.hpp>
 #include <rotgen/config.hpp>
 #include <initializer_list>
 #include <cstddef>
diff --git a/include/rotgen/impl/matrix_model.hpp b/include/rotgen/impl/matrix_model.hpp
index a9bb1d1..2aa814b 100644
--- a/include/rotgen/impl/matrix_model.hpp
+++ b/include/rotgen/impl/matrix_model.hpp
@@ -76,6 +76,7 @@ class ROTGEN_EXPORT CLASSNAME
   CLASSNAME& operator/=(TYPE  d);
 
   friend ROTGEN_EXPORT std::ostream& operator<<(std::ostream&,CLASSNAME const&);
+  friend ROTGEN_EXPORT std::ostream& operator<<(std::ostream&, format<CLASSNAME> const&);
   friend ROTGEN_EXPORT bool operator==(CLASSNAME const& lhs, CLASSNAME const& rhs);
   friend ROTGEN_EXPORT bool operator!=(CLASSNAME const& lhs, CLASSNAME const& rhs);
 
diff --git a/include/rotgen/impl/payload.hpp b/include/rotgen/impl/payload.hpp
index 39c52e4..72ec4b5 100644
--- a/include/rotgen/impl/payload.hpp
+++ b/include/rotgen/impl/payload.hpp
@@ -12,6 +12,7 @@
 #include <rotgen/impl/matrix.hpp>
 #include <rotgen/impl/map.hpp>
 #include <Eigen/Dense>
+#include <Eigen/Core>
 
 namespace rotgen
 {
@@ -181,4 +182,19 @@ namespace rotgen
     payload (double* ptr, Index r, Index c) : data(ptr,r,c) {}
     payload (double* ptr, Index r, Index c, stride_type s) : data(ptr,r,c,s) {}
   };
+
+  //
+    struct ioformat::payload
+  {
+    Eigen::IOFormat instance;
+
+    payload ( int p, int f
+            , std::string const& cs, std::string const& rsp
+            , std::string const& rp, std::string const& rs
+            , std::string const& mp, std::string const& ms
+            , char fill
+            )
+    : instance(p,f,cs,rsp,rp,rs,mp,ms,fill)
+    {}
+  };
 }
diff --git a/include/rotgen/rotgen.hpp b/include/rotgen/rotgen.hpp
index 1787d10..bd42479 100644
--- a/include/rotgen/rotgen.hpp
+++ b/include/rotgen/rotgen.hpp
@@ -17,11 +17,13 @@
 #include <rotgen/dynamic/block.hpp>
 #include <rotgen/dynamic/map.hpp>
 #include <rotgen/dynamic/svd.hpp>
+#include <rotgen/dynamic/format.hpp>
 #else
 #include <rotgen/fixed/matrix.hpp>
 #include <rotgen/fixed/block.hpp>
 #include <rotgen/fixed/map.hpp>
 #include <rotgen/fixed/svd.hpp>
+#include <rotgen/fixed/format.hpp>
 #endif
 
 #include <rotgen/common/ref.hpp>
diff --git a/src/block_indirect.cpp b/src/block_indirect.cpp
index 283ff16..0e08f39 100644
--- a/src/block_indirect.cpp
+++ b/src/block_indirect.cpp
@@ -1,59 +1,66 @@
-  #define SIZE 64
-  #define TYPE double
-  #define STORAGE_ORDER Eigen::ColMajor
+//==================================================================================================
+/*
+  ROTGEN - Runtime Overlay for Eigen
+  Copyright : CODE RECKONS
+  SPDX-License-Identifier: BSL-1.0
+*/
+//==================================================================================================
+#define SIZE 64
+#define TYPE double
+#define STORAGE_ORDER Eigen::ColMajor
 
-  #define CLASSNAME       ROTGEN_MATRIX_NAME(BASENAME,SIZE,_col)
-  #define SOURCENAME      ROTGEN_MATRIX_NAME(matrix_impl,SIZE,_col)
-  #define TRANSSOURCENAME ROTGEN_MATRIX_NAME(matrix_impl,SIZE,_row)
-  #define MAPNAME         ROTGEN_MATRIX_NAME(BASEMAP,SIZE,_col)
-  #include "block_model.cpp"
-  #undef CLASSNAME
-  #undef TRANSSOURCENAME
-  #undef SOURCENAME
-  #undef MAPNAME
-  #undef STORAGE_ORDER
+#define CLASSNAME       ROTGEN_MATRIX_NAME(BASENAME,SIZE,_col)
+#define SOURCENAME      ROTGEN_MATRIX_NAME(matrix_impl,SIZE,_col)
+#define TRANSSOURCENAME ROTGEN_MATRIX_NAME(matrix_impl,SIZE,_row)
+#define MAPNAME         ROTGEN_MATRIX_NAME(BASEMAP,SIZE,_col)
+#include "block_model.cpp"
+#undef CLASSNAME
+#undef TRANSSOURCENAME
+#undef SOURCENAME
+#undef MAPNAME
+#undef STORAGE_ORDER
 
-  #define STORAGE_ORDER Eigen::RowMajor
-  #define CLASSNAME       ROTGEN_MATRIX_NAME(BASENAME,SIZE,_row)
-  #define SOURCENAME      ROTGEN_MATRIX_NAME(matrix_impl,SIZE,_row)
-  #define TRANSSOURCENAME ROTGEN_MATRIX_NAME(matrix_impl,SIZE,_col)
-  #define MAPNAME         ROTGEN_MATRIX_NAME(BASEMAP,SIZE,_row)
-  #include "block_model.cpp"
-  #undef CLASSNAME
-  #undef TRANSSOURCENAME
-  #undef SOURCENAME
-  #undef MAPNAME
-  #undef STORAGE_ORDER
+#define STORAGE_ORDER Eigen::RowMajor
+#define CLASSNAME       ROTGEN_MATRIX_NAME(BASENAME,SIZE,_row)
+#define SOURCENAME      ROTGEN_MATRIX_NAME(matrix_impl,SIZE,_row)
+#define TRANSSOURCENAME ROTGEN_MATRIX_NAME(matrix_impl,SIZE,_col)
+#define MAPNAME         ROTGEN_MATRIX_NAME(BASEMAP,SIZE,_row)
+#include "block_model.cpp"
+#undef CLASSNAME
+#undef TRANSSOURCENAME
+#undef SOURCENAME
+#undef MAPNAME
+#undef STORAGE_ORDER
 
-  #undef SIZE
-  #undef TYPE
+#undef SIZE
+#undef TYPE
 
-  #define SIZE 32
-  #define TYPE float
-  #define STORAGE_ORDER Eigen::ColMajor
+#define SIZE 32
+#define TYPE float
+#define STORAGE_ORDER Eigen::ColMajor
 
-  #define CLASSNAME       ROTGEN_MATRIX_NAME(BASENAME,SIZE,_col)
-  #define SOURCENAME      ROTGEN_MATRIX_NAME(matrix_impl,SIZE,_col)
-  #define TRANSSOURCENAME ROTGEN_MATRIX_NAME(matrix_impl,SIZE,_row)
-  #define MAPNAME         ROTGEN_MATRIX_NAME(BASEMAP,SIZE,_col)
-  #include "block_model.cpp"
-  #undef CLASSNAME
-  #undef TRANSSOURCENAME
-  #undef SOURCENAME
-  #undef MAPNAME
-  #undef STORAGE_ORDER
+#define CLASSNAME       ROTGEN_MATRIX_NAME(BASENAME,SIZE,_col)
+#define SOURCENAME      ROTGEN_MATRIX_NAME(matrix_impl,SIZE,_col)
+#define TRANSSOURCENAME ROTGEN_MATRIX_NAME(matrix_impl,SIZE,_row)
+#define MAPNAME         ROTGEN_MATRIX_NAME(BASEMAP,SIZE,_col)
+#include "block_model.cpp"
+#undef CLASSNAME
+#undef TRANSSOURCENAME
+#undef SOURCENAME
+#undef MAPNAME
+#undef STORAGE_ORDER
 
-  #define STORAGE_ORDER Eigen::RowMajor
-  #define CLASSNAME       ROTGEN_MATRIX_NAME(BASENAME,SIZE,_row)
-  #define SOURCENAME      ROTGEN_MATRIX_NAME(matrix_impl,SIZE,_row)
-  #define TRANSSOURCENAME ROTGEN_MATRIX_NAME(matrix_impl,SIZE,_col)
-  #define MAPNAME         ROTGEN_MATRIX_NAME(BASEMAP,SIZE,_row)
-  #include "block_model.cpp"
-  #undef CLASSNAME
-  #undef TRANSSOURCENAME
-  #undef SOURCENAME
-  #undef MAPNAME
-  #undef STORAGE_ORDER
+#define STORAGE_ORDER Eigen::RowMajor
+#define CLASSNAME       ROTGEN_MATRIX_NAME(BASENAME,SIZE,_row)
+#define SOURCENAME      ROTGEN_MATRIX_NAME(matrix_impl,SIZE,_row)
+#define TRANSSOURCENAME ROTGEN_MATRIX_NAME(matrix_impl,SIZE,_col)
+#define MAPNAME         ROTGEN_MATRIX_NAME(BASEMAP,SIZE,_row)
+#include "block_model.cpp"
+#undef CLASSNAME
+#undef TRANSSOURCENAME
+#undef SOURCENAME
+#undef MAPNAME
+#undef STORAGE_ORDER
 
-  #undef SIZE
-  #undef TYPE
\ No newline at end of file
+#undef SIZE
+#undef TYPE
\ No newline at end of file
diff --git a/src/block_model.cpp b/src/block_model.cpp
index 6ca61e2..889ecc1 100644
--- a/src/block_model.cpp
+++ b/src/block_model.cpp
@@ -394,6 +394,12 @@ struct CLASSNAME::payload
     return os;
   }
 
+  ROTGEN_EXPORT std::ostream& operator<<(std::ostream& os,format<CLASSNAME> const& m)
+  {
+    m.matrix_.storage_->apply([&](const auto& blk) { os << blk.format(m.format_.storage()->instance); });
+    return os;
+  }
+
   ROTGEN_EXPORT bool operator==(CLASSNAME const& lhs, CLASSNAME const& rhs)
   {
     return std::visit ( [](auto const& lhs_blk, auto const& rhs_blk) { return lhs_blk.first == rhs_blk.first; }
diff --git a/src/format.cpp b/src/format.cpp
new file mode 100644
index 0000000..474a13b
--- /dev/null
+++ b/src/format.cpp
@@ -0,0 +1,27 @@
+//==================================================================================================
+/*
+  ROTGEN - Runtime Overlay for Eigen
+  Copyright : CODE RECKONS
+  SPDX-License-Identifier: BSL-1.0
+*/
+//==================================================================================================
+
+#include <rotgen/config.hpp>
+#include <rotgen/dynamic/format.hpp>
+#include <rotgen/impl/payload.hpp>
+#include <Eigen/Core>
+#include <string>
+
+namespace rotgen
+{
+  ioformat::ioformat( int p, int f
+                    , std::string const& cs, std::string const& rsp
+                    , std::string const& rp, std::string const& rs
+                    , std::string const& mp, std::string const& ms
+                    , char fill
+                    )
+          : storage_(std::make_unique<payload>(p,f,cs,rsp,rp,rs,mp,ms,fill))
+  {}
+
+  ioformat::~ioformat() = default;
+}
\ No newline at end of file
diff --git a/src/map_indirect.cpp b/src/map_indirect.cpp
index 402d394..fed2ac7 100644
--- a/src/map_indirect.cpp
+++ b/src/map_indirect.cpp
@@ -1,67 +1,74 @@
-  #define SIZE 64
-  #define TYPE double
-  #define STORAGE_ORDER Eigen::ColMajor
+//==================================================================================================
+/*
+  ROTGEN - Runtime Overlay for Eigen
+  Copyright : CODE RECKONS
+  SPDX-License-Identifier: BSL-1.0
+*/
+//==================================================================================================
+#define SIZE 64
+#define TYPE double
+#define STORAGE_ORDER Eigen::ColMajor
 
-  #define CLASSNAME       ROTGEN_MATRIX_NAME(BASENAME,SIZE,_col)
-  #define TRANSCLASSNAME  ROTGEN_MATRIX_NAME(BASENAME,SIZE,_row)
-  #define TRANSSOURCENAME ROTGEN_MATRIX_NAME(matrix_impl,SIZE,_row)
-  #define CLASSCONSTNAME  ROTGEN_MATRIX_NAME(map_const_impl,SIZE,_col)
-  #define SOURCENAME      ROTGEN_MATRIX_NAME(matrix_impl,SIZE,_col)
-  #include "map_model.cpp"
-  #undef CLASSNAME
-  #undef TRANSCLASSNAME
-  #undef TRANSSOURCENAME
-  #undef CLASSCONSTNAME
-  #undef SOURCENAME
-  #undef STORAGE_ORDER
+#define CLASSNAME       ROTGEN_MATRIX_NAME(BASENAME,SIZE,_col)
+#define TRANSCLASSNAME  ROTGEN_MATRIX_NAME(BASENAME,SIZE,_row)
+#define TRANSSOURCENAME ROTGEN_MATRIX_NAME(matrix_impl,SIZE,_row)
+#define CLASSCONSTNAME  ROTGEN_MATRIX_NAME(map_const_impl,SIZE,_col)
+#define SOURCENAME      ROTGEN_MATRIX_NAME(matrix_impl,SIZE,_col)
+#include "map_model.cpp"
+#undef CLASSNAME
+#undef TRANSCLASSNAME
+#undef TRANSSOURCENAME
+#undef CLASSCONSTNAME
+#undef SOURCENAME
+#undef STORAGE_ORDER
 
-  #define STORAGE_ORDER Eigen::RowMajor
-  #define CLASSNAME       ROTGEN_MATRIX_NAME(BASENAME,SIZE,_row)
-  #define TRANSCLASSNAME  ROTGEN_MATRIX_NAME(BASENAME,SIZE,_col)
-  #define TRANSSOURCENAME ROTGEN_MATRIX_NAME(matrix_impl,SIZE,_col)
-  #define CLASSCONSTNAME  ROTGEN_MATRIX_NAME(map_const_impl,SIZE,_row)
-  #define SOURCENAME      ROTGEN_MATRIX_NAME(matrix_impl,SIZE,_row)
-  #include "map_model.cpp"
-  #undef CLASSNAME
-  #undef TRANSCLASSNAME
-  #undef TRANSSOURCENAME
-  #undef SOURCENAME
-  #undef CLASSCONSTNAME
-  #undef STORAGE_ORDER
+#define STORAGE_ORDER Eigen::RowMajor
+#define CLASSNAME       ROTGEN_MATRIX_NAME(BASENAME,SIZE,_row)
+#define TRANSCLASSNAME  ROTGEN_MATRIX_NAME(BASENAME,SIZE,_col)
+#define TRANSSOURCENAME ROTGEN_MATRIX_NAME(matrix_impl,SIZE,_col)
+#define CLASSCONSTNAME  ROTGEN_MATRIX_NAME(map_const_impl,SIZE,_row)
+#define SOURCENAME      ROTGEN_MATRIX_NAME(matrix_impl,SIZE,_row)
+#include "map_model.cpp"
+#undef CLASSNAME
+#undef TRANSCLASSNAME
+#undef TRANSSOURCENAME
+#undef SOURCENAME
+#undef CLASSCONSTNAME
+#undef STORAGE_ORDER
 
-  #undef SIZE
-  #undef TYPE
+#undef SIZE
+#undef TYPE
 
-  #define SIZE 32
-  #define TYPE float
-  #define STORAGE_ORDER Eigen::ColMajor
+#define SIZE 32
+#define TYPE float
+#define STORAGE_ORDER Eigen::ColMajor
 
-  #define CLASSNAME       ROTGEN_MATRIX_NAME(BASENAME,SIZE,_col)
-  #define TRANSCLASSNAME  ROTGEN_MATRIX_NAME(BASENAME,SIZE,_row)
-  #define TRANSSOURCENAME ROTGEN_MATRIX_NAME(matrix_impl,SIZE,_row)
-  #define CLASSCONSTNAME  ROTGEN_MATRIX_NAME(map_const_impl,SIZE,_col)
-  #define SOURCENAME      ROTGEN_MATRIX_NAME(matrix_impl,SIZE,_col)
-  #include "map_model.cpp"
-  #undef CLASSNAME
-  #undef TRANSCLASSNAME
-  #undef TRANSSOURCENAME
-  #undef CLASSCONSTNAME
-  #undef SOURCENAME
-  #undef STORAGE_ORDER
+#define CLASSNAME       ROTGEN_MATRIX_NAME(BASENAME,SIZE,_col)
+#define TRANSCLASSNAME  ROTGEN_MATRIX_NAME(BASENAME,SIZE,_row)
+#define TRANSSOURCENAME ROTGEN_MATRIX_NAME(matrix_impl,SIZE,_row)
+#define CLASSCONSTNAME  ROTGEN_MATRIX_NAME(map_const_impl,SIZE,_col)
+#define SOURCENAME      ROTGEN_MATRIX_NAME(matrix_impl,SIZE,_col)
+#include "map_model.cpp"
+#undef CLASSNAME
+#undef TRANSCLASSNAME
+#undef TRANSSOURCENAME
+#undef CLASSCONSTNAME
+#undef SOURCENAME
+#undef STORAGE_ORDER
 
-  #define STORAGE_ORDER Eigen::RowMajor
-  #define CLASSNAME       ROTGEN_MATRIX_NAME(BASENAME,SIZE,_row)
-  #define TRANSCLASSNAME  ROTGEN_MATRIX_NAME(BASENAME,SIZE,_col)
-  #define TRANSSOURCENAME ROTGEN_MATRIX_NAME(matrix_impl,SIZE,_col)
-  #define CLASSCONSTNAME  ROTGEN_MATRIX_NAME(map_const_impl,SIZE,_row)
-  #define SOURCENAME      ROTGEN_MATRIX_NAME(matrix_impl,SIZE,_row)
-  #include "map_model.cpp"
-  #undef CLASSNAME
-  #undef TRANSCLASSNAME
-  #undef TRANSSOURCENAME
-  #undef CLASSCONSTNAME
-  #undef SOURCENAME
-  #undef STORAGE_ORDER
+#define STORAGE_ORDER Eigen::RowMajor
+#define CLASSNAME       ROTGEN_MATRIX_NAME(BASENAME,SIZE,_row)
+#define TRANSCLASSNAME  ROTGEN_MATRIX_NAME(BASENAME,SIZE,_col)
+#define TRANSSOURCENAME ROTGEN_MATRIX_NAME(matrix_impl,SIZE,_col)
+#define CLASSCONSTNAME  ROTGEN_MATRIX_NAME(map_const_impl,SIZE,_row)
+#define SOURCENAME      ROTGEN_MATRIX_NAME(matrix_impl,SIZE,_row)
+#include "map_model.cpp"
+#undef CLASSNAME
+#undef TRANSCLASSNAME
+#undef TRANSSOURCENAME
+#undef CLASSCONSTNAME
+#undef SOURCENAME
+#undef STORAGE_ORDER
 
-  #undef SIZE
-  #undef TYPE
+#undef SIZE
+#undef TYPE
diff --git a/src/map_model.cpp b/src/map_model.cpp
index 56e1a7f..da87ce3 100644
--- a/src/map_model.cpp
+++ b/src/map_model.cpp
@@ -265,6 +265,11 @@
     return os << m.storage_->data;
   }
 
+  ROTGEN_EXPORT std::ostream& operator<<(std::ostream& os,format<CLASSNAME> const& m)
+  {
+    return os << m.matrix_.storage_->data.format(m.format_.storage()->instance);
+  }
+
   ROTGEN_EXPORT bool operator==(CLASSNAME const& lhs, CLASSNAME const& rhs)
   {
     return lhs.storage_->data == rhs.storage_->data;
diff --git a/src/matrix_model.cpp b/src/matrix_model.cpp
index 96c8de2..a4131d7 100644
--- a/src/matrix_model.cpp
+++ b/src/matrix_model.cpp
@@ -175,6 +175,11 @@ ROTGEN_EXPORT std::ostream& operator<<(std::ostream& os,CLASSNAME const& m)
   return os << m.storage_->data;
 }
 
+ROTGEN_EXPORT std::ostream& operator<<(std::ostream& os,format<CLASSNAME> const& m)
+{
+  return os << m.matrix_.storage_->data.format(m.format_.storage()->instance);
+}
+
 ROTGEN_EXPORT bool operator==(CLASSNAME const& lhs, CLASSNAME const& rhs)
 {
   return lhs.storage_->data == rhs.storage_->data;
diff --git a/test/unit/io.cpp b/test/integration/io.cpp
similarity index 55%
rename from test/unit/io.cpp
rename to test/integration/io.cpp
index 698063c..be69613 100644
--- a/test/unit/io.cpp
+++ b/test/integration/io.cpp
@@ -45,3 +45,42 @@ TTS_CASE_TPL("I/O for map test", rotgen::tests::types)
   if constexpr(O::value)  TTS_EQUAL(os.str(), std::string{"1 2\n3 4"});
   else                    TTS_EQUAL(os.str(), std::string{"1 3\n2 4"});
 };
+
+TTS_CASE_TPL("I/O using format", rotgen::tests::types)
+<typename T, typename O>( tts::type< tts::types<T,O>> )
+{
+  rotgen::ioformat io(rotgen::StreamPrecision, 0, ", ", ";\n", "<", ">", "[", "]");
+
+  rotgen::matrix<T,rotgen::Dynamic,rotgen::Dynamic,O::value> x({ {1,2} , {3,4} });
+
+  {
+    std::ostringstream os;
+    os << rotgen::format(x,io);
+    TTS_EQUAL(os.str(), std::string{"[<1, 2>;\n <3, 4>]"});
+  }
+
+  rotgen::map<rotgen::matrix<T,2,2,O::value>> m{x.data()};
+  {
+    std::ostringstream os;
+    os << rotgen::format(m,io);
+    TTS_EQUAL(os.str(), std::string{"[<1, 2>;\n <3, 4>]"});
+  }
+
+  auto b = rotgen::extract(x,0,0,2,2);
+  {
+    std::ostringstream os;
+    os << rotgen::format(b,io);
+    TTS_EQUAL(os.str(), std::string{"[<1, 2>;\n <3, 4>]"});
+  }
+
+  auto printer = [&](rotgen::ref<const rotgen::matrix<T,rotgen::Dynamic,rotgen::Dynamic,O::value>> r)
+  {
+    std::ostringstream st;
+    st << rotgen::format(r,io);
+    return st.str();
+  };
+
+  TTS_EQUAL(printer(x), std::string{"[<1, 2>;\n <3, 4>]"});
+  TTS_EQUAL(printer(m), std::string{"[<1, 2>;\n <3, 4>]"});
+  TTS_EQUAL(printer(b), std::string{"[<1, 2>;\n <3, 4>]"});
+};