Mercurial > repos > public > sbplib
diff +sbp/+implementations/d2_variable_periodic_2.m @ 681:7368affc8f78 feature/poroelastic
Add D2 variable periodic for second order.
author | Martin Almquist <malmquist@stanford.edu> |
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date | Wed, 07 Feb 2018 15:42:50 -0800 |
parents | |
children | 5ccf6aaf6d6b |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/+sbp/+implementations/d2_variable_periodic_2.m Wed Feb 07 15:42:50 2018 -0800 @@ -0,0 +1,51 @@ +function [H, HI, D1, D2, e_l, e_r, d1_l, d1_r] = d2_variable_periodic_2(m,h) + % m = number of unique grid points, i.e. h = L/m; + + BP = 1; + if(m<2*BP) + error(['Operator requires at least ' num2str(2*BP) ' grid points']); + end + + % Norm + Hv = ones(m,1); + Hv = h*Hv; + H = spdiag(Hv, 0); + HI = spdiag(1./Hv, 0); + + + % Dummy boundary operators + e_l = sparse(m,1); + e_r = rot90(e_l, 2); + + d1_l = sparse(m,1); + d1_r = -rot90(d1_l, 2); + + % D1 operator + diags = -1:1; + stencil = [-1/2 0 1/2]; + D1 = stripeMatrixPeriodic(stencil, diags, m); + D1 = D1/h; + + scheme_width = 3; + scheme_radius = (scheme_width-1)/2; + + r = 1:m; + offset = scheme_width; + r = r + offset; + + function D2 = D2_fun(c) + c = [c(end-scheme_width+1:end); c; c(1:scheme_width) ]; + + Mm1 = -c(r-1)/2 - c(r)/2; + M0 = c(r-1)/2 + c(r) + c(r+1)/2; + Mp1 = -c(r)/2 - c(r+1)/2; + + vals = [Mm1,M0,Mp1]; + diags = -scheme_radius : scheme_radius; + M = spdiagsVariablePeriodic(vals,diags); + + M=M/h; + D2=HI*(-M ); + end + D2 = @D2_fun; +end \ No newline at end of file