Hi To use multi_array with user defined types, is there any restriction on the user defined types? When I tried compiler generates so many error messages like this: My definition is like this: typedef boost::multi_array<score, 2> array_type; //score is defined as a structure typedef array_type::index Index; Error messages: /usr/include/boost/multi_array/subarray.hpp:238: error: ‘const struct score’ has no member named ‘num_dimensions’ /usr/include/boost/multi_array/subarray.hpp:239: error: ‘const struct score’ has no member named ‘shape’ /usr/include/boost/multi_array/subarray.hpp:239: error: ‘const struct score’ has no member named ‘shape’ scoreAnalysis.cpp:34: instantiated from here /usr/include/boost/multi_array/subarray.hpp:242: error: ‘const struct score’ has no member named ‘begin’ /usr/include/boost/multi_array/subarray.hpp:242: error: ‘const struct score’ has no member named ‘end’ thanks suresh -- R Suresh Kumar, http://www.ee.ucr.edu/~sramachandranna Sarve bhavantu sukinaha (May everyone be happy) Sarve santu niramiyaha (May everyone be without affliction) Sarve bhadrani pashyantu (May everyone see only goodness) Ma kashchit dukha bhak bhavet (Let none be the victim of suffering)