Re: [Boost-users] [multi_array] how to modify the dimension of an array?

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 r0d wrote:

Hello everybody,

i'm looking for the best way to modify the dimensions of an array. For example, i got this one:

boost::multi_array array ( boost::extents[3][3] );

and i want to change it in an array of 5 dimensions.

Now, what i'm doing is to create a new array of 5 dimensions and copying the first one into it, then delete the first one. But i'm sure that a more efficient way exists. No?

use resize() - see below TEST(multi_array) { boost::multi_array myArray ( boost::extents[3][3] ); int values = 0; for(boost::multi_array::index i = 0; i != 3; ++i) { for(boost::multi_array::index j = 0; j != 3; ++j) { myArray[i][j] = values++; } } // Verify values int verify1 = 0; for(boost::multi_array::index i = 0; i != 3; ++i) { for(boost::multi_array::index j = 0; j != 3; ++j) { CHECK_EQUAL(myArray[i][j],verify1++); } } myArray.resize(boost::extents[5][5]); //continue setting 'values' in the newly added array space for(boost::multi_array::index i = 3; i != 5; ++i) { for(boost::multi_array::index j = 3; j != 5; ++j) { myArray[i][j] = values++; } } //check the original data is still there int verify2 = 0; for(boost::multi_array::index i = 0; i != 3; ++i) { for(boost::multi_array::index j = 0; j != 3; ++j) { CHECK_EQUAL(myArray[i][j],verify2++); } } //check that the new array space has correct values for(boost::multi_array::index i = 3; i != 5; ++i) { for(boost::multi_array::index j = 3; j != 5; ++j) { CHECK_EQUAL(myArray[i][j],verify1++); } } } -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (GNU/Linux) Comment: Using GnuPG with Fedora - http://enigmail.mozdev.org iD8DBQFIQGnW/X5Z5iyVCbERAmCmAJ4qgpbHzcUYqGor8kDUabQfDHwCLQCfZ7EH dTGc5PybZhGR0zgyUxx92q0= =VwiS -----END PGP SIGNATURE-----