Ritz method is one of the techniques for reduction of the degrees of freedom. Efficiency of Ritz method depends on used vectors. The Ritz method uses load depended vectors in spite of modal method and for this reason it is expected to give better results than modal method. This is the advantage of Ritz method. It is worth mention that the mode shapes are independent of loading. The vectors that...

A convergence analysis to the weak solution is derived for interior penalty discontinuous Galerkin methods applied to the heat equation in two and three dimensions under general mixed boundary conditions. Strong convergence is established in the DG norm, as well as in the L norm, in space and in the L norm in time.

Article history: Received 12 September 2013 Received in revised form 8 April 2014 Accepted 3 July 2014 Available online 15 July 2014

Article history: Received 21 February 2012 Received in revised form 30 May 2012 Accepted 4 June 2012 Available online 16 June 2012

Article history: Received 27 March 2011 Accepted 3 May 2012 Available online 15 May 2012