pde2_4th.c running 
sum2,4 are L2 norm of errors 
dif2,4 are average difference from analytic solution 
xmin=0, xmax=1, ymin=0, ymax=1 
hval=1, h=0.1, n=10 
m=101, dif4=4.54536e-05, dif2=0.000102141, maxdif=0.000211759, maxerr=0.00419316 
m=102, dif4=4.28058e-05, dif2=9.7139e-05, maxdif=0.00019337, maxerr=0.0039814 
m=103, dif4=4.03122e-05, dif2=9.2387e-05, maxdif=0.000191538, maxerr=0.00378803 
m=104, dif4=3.79639e-05, dif2=8.78631e-05, maxdif=0.000174905, maxerr=0.00359649 
m=105, dif4=3.57524e-05, dif2=8.35649e-05, maxdif=0.000173248, maxerr=0.00342158 
m=106, dif4=3.36697e-05, dif2=7.94729e-05, maxdif=0.000158203, maxerr=0.00324834 
m=107, dif4=3.17083e-05, dif2=7.55851e-05, maxdif=0.000156704, maxerr=0.00309013 
m=108, dif4=2.98612e-05, dif2=7.18839e-05, maxdif=0.000143096, maxerr=0.00293343 
m=109, dif4=2.81217e-05, dif2=6.83674e-05, maxdif=0.00014174, maxerr=0.00279033 
m=110, dif4=2.64835e-05, dif2=6.50196e-05, maxdif=0.000129432, maxerr=0.00264859 
m=111, dif4=2.49408e-05, dif2=6.18389e-05, maxdif=0.000128205, maxerr=0.00251916 
m=112, dif4=2.34879e-05, dif2=5.88108e-05, maxdif=0.000117072, maxerr=0.00239096 
m=113, dif4=2.21197e-05, dif2=5.59338e-05, maxdif=0.000115963, maxerr=0.00227388 
m=114, dif4=2.08311e-05, dif2=5.31948e-05, maxdif=0.000105893, maxerr=0.00215792 
m=115, dif4=1.96176e-05, dif2=5.05926e-05, maxdif=0.000104889, maxerr=0.00205203 
m=116, dif4=1.84749e-05, dif2=4.81152e-05, maxdif=9.57808e-05, maxerr=0.00194714 
us[0][0]=0, u=0, dif4=0 
us[0][1]=0.0998334, u=0.0998334, dif4=0 
us[0][2]=0.198669, u=0.198669, dif4=0 
us[0][3]=0.29552, u=0.29552, dif4=0 
us[0][4]=0.389418, u=0.389418, dif4=0 
us[0][5]=0.479426, u=0.479426, dif4=0 
us[0][6]=0.564642, u=0.564642, dif4=0 
us[0][7]=0.644218, u=0.644218, dif4=0 
us[0][8]=0.717356, u=0.717356, dif4=0 
us[0][9]=0.783327, u=0.783327, dif4=0 
us[0][10]=0.841471, u=0.841471, dif4=0 
us[1][0]=0, u=0, dif4=0 
us[1][1]=0.0992767, u=0.0993347, dif4=-5.79533e-05 
us[1][2]=0.197567, u=0.197677, dif4=-0.000110234 
us[1][3]=0.293892, u=0.294044, dif4=-0.000151725 
us[1][4]=0.387295, u=0.387473, dif4=-0.000178365 
us[1][5]=0.476843, u=0.47703, dif4=-0.000187546 
us[1][6]=0.561643, u=0.561822, dif4=-0.000178369 
us[1][7]=0.640848, u=0.640999, dif4=-0.000151731 
us[1][8]=0.713662, u=0.713772, dif4=-0.000110241 
us[1][9]=0.779356, u=0.779414, dif4=-5.79582e-05 
us[1][10]=0.837267, u=0.837267, dif4=0 
us[2][0]=0, u=0, dif4=0 
us[2][1]=0.0977332, u=0.0978434, dif4=-0.000110233 
us[2][2]=0.194499, u=0.194709, dif4=-0.000209677 
us[2][3]=0.289341, u=0.289629, dif4=-0.000288597 
us[2][4]=0.381317, u=0.381656, dif4=-0.000339269 
us[2][5]=0.469512, u=0.469869, dif4=-0.000356732 
us[2][6]=0.553048, u=0.553387, dif4=-0.000339275 
us[2][7]=0.631088, u=0.631376, dif4=-0.000288608 
us[2][8]=0.702847, u=0.703057, dif4=-0.000209688 
us[2][9]=0.767602, u=0.767713, dif4=-0.000110241 
us[2][10]=0.824698, u=0.824698, dif4=0 
us[3][0]=0, u=0, dif4=0 
us[3][1]=0.0952228, u=0.0953745, dif4=-0.000151723 
us[3][2]=0.189507, u=0.189796, dif4=-0.000288595 
us[3][3]=0.281924, u=0.282321, dif4=-0.000397219 
us[3][4]=0.371559, u=0.372026, dif4=-0.000466962 
us[3][5]=0.457522, u=0.458013, dif4=-0.000490997 
us[3][6]=0.538957, u=0.539424, dif4=-0.00046697 
us[3][7]=0.615047, u=0.615445, dif4=-0.000397232 
us[3][8]=0.685028, u=0.685316, dif4=-0.000288609 
us[3][9]=0.748189, u=0.748341, dif4=-0.000151733 
us[3][10]=0.803888, u=0.803888, dif4=0 
us[4][0]=0, u=0, dif4=0 
us[4][1]=0.0917743, u=0.0919527, dif4=-0.00017836 
us[4][2]=0.182647, u=0.182987, dif4=-0.000339262 
us[4][3]=0.271725, u=0.272192, dif4=-0.000466957 
us[4][4]=0.358129, u=0.358678, dif4=-0.000548945 
us[4][5]=0.441003, u=0.44158, dif4=-0.000577199 
us[4][6]=0.519521, u=0.52007, dif4=-0.000548954 
us[4][7]=0.592897, u=0.593364, dif4=-0.000466972 
us[4][8]=0.660389, u=0.660729, dif4=-0.000339279 
us[4][9]=0.721313, u=0.721492, dif4=-0.000178371 
us[4][10]=0.775046, u=0.775046, dif4=0 
us[5][0]=0, u=0, dif4=0 
us[5][1]=0.0874245, u=0.0876121, dif4=-0.000187539 
us[5][2]=0.173992, u=0.174349, dif4=-0.000356721 
us[5][3]=0.258852, u=0.259343, dif4=-0.000490987 
us[5][4]=0.34117, u=0.341747, dif4=-0.000577193 
us[5][5]=0.420129, u=0.420735, dif4=-0.000606901 
us[5][6]=0.494943, u=0.49552, dif4=-0.000577203 
us[5][7]=0.564863, u=0.565354, dif4=-0.000491002 
us[5][8]=0.629182, u=0.629539, dif4=-0.000356737 
us[5][9]=0.687246, u=0.687434, dif4=-0.00018755 
us[5][10]=0.73846, u=0.73846, dif4=0 
us[6][0]=0, u=0, dif4=0 
us[6][1]=0.0822177, u=0.0823961, dif4=-0.000178359 
us[6][2]=0.16363, u=0.163969, dif4=-0.000339261 
us[6][3]=0.243436, u=0.243903, dif4=-0.000466955 
us[6][4]=0.320852, u=0.321401, dif4=-0.000548942 
us[6][5]=0.39511, u=0.395687, dif4=-0.000577196 
us[6][6]=0.465471, u=0.46602, dif4=-0.000548951 
us[6][7]=0.531229, u=0.531696, dif4=-0.00046697 
us[6][8]=0.59172, u=0.59206, dif4=-0.000339277 
us[6][9]=0.646329, u=0.646508, dif4=-0.00017837 
us[6][10]=0.694496, u=0.694496, dif4=0 
us[7][0]=0, u=0, dif4=0 
us[7][1]=0.0762051, u=0.0763568, dif4=-0.000151721 
us[7][2]=0.151662, u=0.151951, dif4=-0.000288592 
us[7][3]=0.225629, u=0.226026, dif4=-0.000397215 
us[7][4]=0.297377, u=0.297844, dif4=-0.000466958 
us[7][5]=0.366194, u=0.366685, dif4=-0.000490992 
us[7][6]=0.431395, u=0.431862, dif4=-0.000466965 
us[7][7]=0.492328, u=0.492725, dif4=-0.000397228 
us[7][8]=0.548376, u=0.548664, dif4=-0.000288606 
us[7][9]=0.59897, u=0.599121, dif4=-0.000151731 
us[7][10]=0.643593, u=0.643593, dif4=0 
us[8][0]=0, u=0, dif4=0 
us[8][1]=0.0694444, u=0.0695546, dif4=-0.000110232 
us[8][2]=0.138205, u=0.138414, dif4=-0.000209674 
us[8][3]=0.205602, u=0.205891, dif4=-0.000288594 
us[8][4]=0.270971, u=0.27131, dif4=-0.000339264 
us[8][5]=0.333662, u=0.334019, dif4=-0.000356727 
us[8][6]=0.393051, u=0.39339, dif4=-0.00033927 
us[8][7]=0.448542, u=0.448831, dif4=-0.000288603 
us[8][8]=0.499577, u=0.499787, dif4=-0.000209685 
us[8][9]=0.545639, u=0.545749, dif4=-0.000110239 
us[8][10]=0.586258, u=0.586258, dif4=0 
us[9][0]=0, u=0, dif4=0 
us[9][1]=0.0619995, u=0.0620574, dif4=-5.79524e-05 
us[9][2]=0.123385, u=0.123495, dif4=-0.000110232 
us[9][3]=0.183547, u=0.183698, dif4=-0.000151723 
us[9][4]=0.241888, u=0.242066, dif4=-0.000178362 
us[9][5]=0.297828, u=0.298016, dif4=-0.000187542 
us[9][6]=0.350809, u=0.350987, dif4=-0.000178365 
us[9][7]=0.4003, u=0.400452, dif4=-0.000151728 
us[9][8]=0.445805, u=0.445916, dif4=-0.000110238 
us[9][9]=0.486866, u=0.486924, dif4=-5.79565e-05 
us[9][10]=0.523067, u=0.523067, dif4=0 
us[10][0]=0, u=0, dif4=0 
us[10][1]=0.0539402, u=0.0539402, dif4=0 
us[10][2]=0.107341, u=0.107341, dif4=0 
us[10][3]=0.15967, u=0.15967, dif4=0 
us[10][4]=0.210404, u=0.210404, dif4=0 
us[10][5]=0.259035, u=0.259035, dif4=0 
us[10][6]=0.305078, u=0.305078, dif4=0 
us[10][7]=0.348072, u=0.348072, dif4=0 
us[10][8]=0.387589, u=0.387589, dif4=0 
us[10][9]=0.423233, u=0.423233, dif4=0 
us[10][10]=0.454649, u=0.454649, dif4=0 
sum4=0.000337168, sum2=0.00102517 
hval=2, h=0.05, n=20 
m=401, dif4=1.12308e-05, dif2=2.51426e-05, maxdif=5.65008e-05, maxerr=0.00455408 
sum4=0.000883237, sum2=0.00236654 
ratio4=2.61957, ratio2=2.30844 
 
hval=3, h=0.025, n=40 
m=1601, dif4=2.72946e-06, dif2=6.10469e-06, maxdif=1.43516e-05, maxerr=0.00464669 
sum4=0.000885613, sum2=0.0023754 
ratio4=1.00269, ratio2=1.00374 
 
hval=4, h=0.0125, n=80 
m=6401, dif4=6.69132e-07, dif2=1.49622e-06, maxdif=3.60211e-06, maxerr=0.00466999 
sum4=0.000880662, sum2=0.00236269 
ratio4=0.994409, ratio2=0.99465