tri_int.c running 
Triangle P1(1,1) P2(3,2.5) P3(2,0.5) 
Length 1 2 =2.5 
Length from 3 to 1 2 =1 
Area of triangle = 1.25 
Area by points = 1.25 
xmin=1, xmax=3, ymin=0.5, ymax=2.5 
n=100, hx=0.02, hy=0.02 

f1(x,y)=x+2*y+3 
integral f1(x,y) over triangle = 9.58408, nn=3125 
exact integral=9.58333, error=0.000745933 
f2(x,y)=x*x+2*y*y+3*x*y+4*x+5*y+6 
integral f2(x,y) over triangle = 46.4182, nn=3125 
exact integral=46.4062, error=0.0119836 
f3(x,y)=x*x*x+2*y*y*y+3*x*x*y+4*x*y*y+5*x*x+6*y*y+7*x*y+ 
        8*x+9*y+10 
integral f3(x,y) over triangle = 176.059, nn=3125 
exact integral=175.99, error=0.0697327 
fe(x,y)=exp(x)*exp(y) 
integral fe(x,y) over triangle = 48.6179, nn=3125 
exact integral=48.5116, error=0.106249 

linear,first order integral=9.58333, using x=2, y=1.33333 
exact integral=9.58333, error=3.33333e-10 
quad,first order integral=45.2778, using x=2, y=1.33333 
exact integral=46.4062, error=-1.12847 
cubic,first order integral=162.87, using x=2, y=1.33333 
exact integral=175.99, error=-13.1192 
exp,first order integral=35.0395, using x=2, y=1.33333 
exact integral=48.5116, error=-13.4721 

linear,second order integral=9.58333, using 3 b points 
exact integral=9.58333, error=3.33333e-10 
quad,second order integral=46.4062, using 3 b points 
exact integral=46.4062, error=0 
cubic,second order integral=175.104, using 3 b points 
exact integral=175.99, error=-0.885417 
exp,second order integral=44.4196, using 3 b points 
exact integral=48.5116, error=-4.09205 

linear,second order integral=9.72222, using 3 c points 
exact integral=9.58333, error=0.138889 
quad,second order integral=48.5012, using 3 c points 
exact integral=46.4062, error=2.09491 
cubic,second order integral=192.033, using 3 c points 
exact integral=175.99, error=16.0436 
exp,second order integral=61.8566, using 3 c points 
exact integral=48.5116, error=13.345 

third order integral=61.8566, using 3 c and a points 
quartic O(h^5) f1 integral=9.58333, using 3 c and 3 d points 
exact integral=9.58333, error=-1.14742e-07 
quartic O(h^5) f2 integral=46.4062, using 3 c and 3 d points 
exact integral=46.4062, error=-6.71541e-07 
quartic O(h^5) f3 integral=175.99, using 3 c and 3 d points 
exact integral=175.99, error=-3.09768e-06 
quartic O(h^5) fe integral=48.5326, using 3 c and 3 d points 
exact integral=48.5116, error=0.0209341 

nvert=3, npoly=1 
f1 split integral=9.58333, using 1 points 
f2 split integral=45.2778, using 1 points 
f3 split integral=162.87, using 1 points 
fe split integral=35.0395, using 1 points 

nvert=6, npoly=4 
f1 split integral=9.58333, using 4 points 
f2 split integral=46.1241, using 4 points 
f3 split integral=172.784, using 4 points 
fe split integral=44.9134, using 4 points 

nvert=18, npoly=16 
f1 split integral=9.58333, using 16 points 
f2 split integral=46.3357, using 16 points 
f3 split integral=175.193, using 16 points 
fe split integral=47.6067, using 16 points 

nvert=66, npoly=64 
f1 split integral=9.58333, using 64 points 
f2 split integral=46.3886, using 64 points 
f3 split integral=175.791, using 64 points 
fe split integral=48.2853, using 64 points 

nvert=258, npoly=256 
f1 split integral=9.58333, using 256 points, error=3.33332e-10 
f2 split integral=46.4018, using 256 points, error=-0.00440809 
f3 split integral=175.94, using 256 points, error=-0.0497157 
fe split integral=48.455, using 256 points, error=-0.0565862 

triquad with coordinate shift
triquad f1 order=1 integral=9.58331 
exact integral=9.58333, error=-2.0833e-05 
triquad f2 order=1 integral=45.2776 
exact integral=46.4062, error=-1.12869 
triquad f3 order=1 integral=162.869 
exact integral=175.99, error=-13.1205 
triquad fe order=1 integral=35.0391 
exact integral=48.5116, error=-13.4726 

triquad f1 order=2 integral=9.58333 
exact integral=9.58333, error=-2.22075e-06 
triquad f2 order=2 integral=46.4062 
exact integral=46.4062, error=-2.74462e-05 
triquad f3 order=2 integral=175.989 
exact integral=175.99, error=-0.000179137 
triquad fe order=2 integral=47.9104 
exact integral=48.5116, error=-0.601239 

triquad f1 order=3 integral=9.58348 
exact integral=9.58333, error=0.000145064 
triquad f2 order=3 integral=46.407 
exact integral=46.4062, error=0.000756211 
triquad f3 order=3 integral=175.993 
exact integral=175.99, error=0.0030211 
triquad fe order=3 integral=48.5022 
exact integral=48.5116, error=-0.00939934 

triquad f1 order=4 integral=9.58336 
exact integral=9.58333, error=2.27616e-05 
triquad f2 order=4 integral=46.4064 
exact integral=46.4062, error=0.000131875 
triquad f3 order=4 integral=175.99 
exact integral=175.99, error=0.000585223 
triquad fe order=4 integral=48.5117 
exact integral=48.5116, error=0.000125853 

triquad f1 order=5 integral=9.58333 
exact integral=9.58333, error=1.35984e-06 
triquad f2 order=5 integral=46.4063 
exact integral=46.4062, error=2.7785e-05 
triquad f3 order=5 integral=175.99 
exact integral=175.99, error=0.000205958 
triquad fe order=5 integral=48.5118 
exact integral=48.5116, error=0.000158248