test_inverse.c on tough matrix to invert 
initializing big matrix, n=2, n*n=4 
data 
AA[0][0]=0.5 
AA[0][1]=0.333333 
AA[1][0]=0.333333 
AA[1][1]=0.25 
inverse 
AI[0][0]=18 
AI[0][1]=-24 
AI[1][0]=-24 
AI[1][1]=36 
AI[2][2]=36 
sum of error=1.84748e-16, avg error=4.6187e-17 
initializing big matrix, n=4, n*n=16 
data 
AA[0][0]=0.5 
AA[0][1]=0.333333 
AA[0][2]=0.25 
AA[0][3]=0.2 
AA[1][0]=0.333333 
AA[1][1]=0.25 
AA[1][2]=0.2 
AA[1][3]=0.166667 
AA[2][0]=0.25 
AA[2][1]=0.2 
AA[2][2]=0.166667 
AA[2][3]=0.142857 
AA[3][0]=0.2 
AA[3][1]=0.166667 
AA[3][2]=0.142857 
AA[3][3]=0.125 
inverse 
AI[0][0]=200 
AI[0][1]=-1200 
AI[0][2]=2100 
AI[0][3]=-1120 
AI[1][0]=-1200 
AI[1][1]=8100 
AI[1][2]=-15120 
AI[1][3]=8400 
AI[2][0]=2100 
AI[2][1]=-15120 
AI[2][2]=29400 
AI[2][3]=-16800 
AI[3][0]=-1120 
AI[3][1]=8400 
AI[3][2]=-16800 
AI[3][3]=9800 
AI[4][4]=9800 
sum of error=2.19971e-12, avg error=1.37482e-13 
initializing big matrix, n=8, n*n=64 
AI[8][8]=6.62548e+08 
sum of error=6.04139e-06, avg error=9.43968e-08 
initializing big matrix, n=16, n*n=256 
AI[16][16]=5.23313e+14 
sum of error=83.9631, avg error=0.327981 
initializing big matrix, n=32, n*n=1024 
AI[32][32]=1.65588e+16 
sum of error=4079.57, avg error=3.98395 
initializing big matrix, n=64, n*n=4096 
AI[64][64]=-3.5311e+16 
sum of error=53735.9, avg error=13.1191 
initializing big matrix, n=128, n*n=16384 
AI[128][128]=4.8628e+16 
sum of error=85784.3, avg error=5.23586 
initializing big matrix, n=256, n*n=65536 
AI[256][256]=6.75496e+17 
sum of error=1.09712e+06, avg error=16.7407 
initializing big matrix, n=512, n*n=262144 
AI[512][512]=6.30324e+17 
sum of error=1.36281e+07, avg error=51.9872 
initializing big matrix, n=1024, n*n=1048576 
AI[1024][1024]=-1.79517e+19 
sum of error=1.24247e+09, avg error=1184.92 
finished test_inverse.c