fig4_12

 FIG4_12  Script to produce Fig 4.12 (top-left) and ,Fig 4.13 (top-left) pag. 204 CHQZ2
 
 Legendre collocation/ G-NI / generalized G-NI first-derivative eigenvalues

 Reference: CHQZ2 = C. Canuto, M.Y. Hussaini, A. Quarteroni, T.A. Zang,
                    "Spectral Methods. Fundamentals in Single Domains"
                    Springer Verlag, Berlin Heidelberg New York, 2006.

0001 % FIG4_12  Script to produce Fig 4.12 (top-left) and ,Fig 4.13 (top-left) pag. 204 CHQZ2
0002 %
0003 % Legendre collocation/ G-NI / generalized G-NI first-derivative eigenvalues
0004 %
0005 % Reference: CHQZ2 = C. Canuto, M.Y. Hussaini, A. Quarteroni, T.A. Zang,
0006 %                    "Spectral Methods. Fundamentals in Single Domains"
0007 %                    Springer Verlag, Berlin Heidelberg New York, 2006.
0008 
0009 %   Written by Paola Gervasio
0010 %   $Date: 2007/04/01$
0011 
0012 
0013 
0014     nu=1;
0015 fig=figure(...,
0016     'Name',['Fig. 4.12'],...
0017     'Visible','on');
0018 
0019 nx=16 % or nx= ....
0020     pbl=0;
0021     [d,A]=lgl_eig(nx,nu,pbl);
0022 plot(real(d),imag(d),'ko'); 
0023 hold on
0024     pbl=1;
0025     [d,A]=lgl_eig(nx,nu,pbl);
0026 plot(real(d),imag(d),'k*');
0027     pbl=2;
0028     [d,A]=lgl_eig(nx,nu,pbl);
0029 plot(real(d),imag(d),'k>');
0030 legend('LC','LG-NI','Gen LG-NI',2);
0031 grid on
0032 xlabel('Real'); ylabel('Imag');