-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 11/11/15 12:02, Anna Kalogirou wrote:
Also, I don't really understand what the difference is between forming the matrix or taking its action...
So if you form the matrix, then you have A, and you can do things like explicitly compute its inverse (using LU, say). If you only give me the action, you don't have A, you just give me a recipe for computing Ax if I give you x. In this case, I don't know what the entries of A are (so I can't explicitly compute its inverse). Lawrence -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) iQEcBAEBAgAGBQJWQzB5AAoJECOc1kQ8PEYvugEIAPEyk/4lVpt1f0G/NSnoPOoX DK4FD+Kjydg+h2sKWx8U0wyIJEvh442vQ3wgtWj+iNVrt9MG8i2dMADUZugvYnc0 IUqLLE8AvHBkLY0++8qe2MPw4tCeX/r09OB3hMXo/39R//KjK3RnRGd0WNe7xncn aJC/1VrfJqxmJvyzYFps5bBIloTA+Gz6C3XZyr44k0xpjQRFnPBgIGp0AXBtVmei cXA1k/3F4TUrA1jFjNC1cNODtrI4V1+Hi9Amgs6XWj5Prk/370dC3sGDGeAO0x2i UH7LVPgsdFo6vsAF0TjOa8zQWEhvw7Iuhx//CtArIO3/dGen3gVQ0CMhVALntSY= =OLyo -----END PGP SIGNATURE-----