Example /***********begin**************/ void testMatrixRow() { matrix<double> m(1920, 1080); clock_t begin,end; begin = clock(); for(unsigned int i = 0; i < m.size1(); ++i) for(unsigned int j = 0; j < m.size2(); j++) { m.insert_element(i, j, i*3 + j); } end = clock(); cout<<"time of inserting data : "<<(double)(end-begin)/CLOCKS_PER_SEC<<" "<<endl; ofstream ob1("testing.txt",ios::out,ios::binary); begin = clock(); for (unsigned i = 0; i < m.size1 (); ++ i) { for(unsigned int j = 0; j < m.size2(); j++) ob1<<m(i, j); } end = clock(); cout<<"time of regular output : "<<(double)(end-begin)/CLOCKS_PER_SEC<<" "<<endl; begin = clock(); for (unsigned i = 0; i < m.size1 (); ++ i) { matrix_row<matrix<double> > mr(m, i); ob1.write((const char*)&mr(0), mr.size()); ob1<<endl; } end = clock(); cout<<"time of nonregular output : "<<(double)(end-begin)/CLOCKS_PER_SEC<<" "<<endl; ob1.close(); } /***********end**************/ As expected,ob1.write is much more faster than ob1<< But the results are not I want(ob1<< is) Do I have any way to solve this problem? Thanks a lot -- View this message in context: http://old.nabble.com/how-could-I-output-the-data-of-matrix%28ublas%29-to-tx... Sent from the Boost - Users mailing list archive at Nabble.com.