取高斯积分点求积的精度有多高
如图：光滑曲线由其他数值积分得到；（quadl）
另条曲线是取了8个高斯积分点。
%Gause积分点与权系数
root=[-0.9602898564975363,-0.7966664774136268,-0.525532409916329,-0.1834346424956498,0.1834346424956498,...
0.525532409916329,0.7966664774136268,0.9602898564975363];
weight=[0.1012285362903768,0.2223810344533745,0.3137066458778874,0.362683783378362,0.362683783378362,...
0.3137066458778874,0.2223810344533745,0.1012285362903768];
两者结果相差较大。
原因分析：
1。两种方法之1有错。
2。高斯积分点精度差.
愿高手指点。。。
[ 本帖最后由 eight 于 2007-11-21 16:55 编辑 ] 数值积分的系列函数的精度可以设置，help里有
Q = QUADL(FUN,A,B,TOL) uses an absolute error tolerance of TOL
instead of the default, which is 1.e-6.Larger values of TOL
result in fewer function evaluations and faster computation,
but less accurate results.
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