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<>在网下载了matlab数值积分工具箱nit安装之后，看了一下里面的基本函数，然后想用其中几个试试看，比如先help quadg察看quadg函数的用法，帮助文件如下：<BR><BR>usage: int = quadg('Fun',xlow,xhigh)<BR>or<BR> int = quadg('Fun',xlow,xhigh,tol)<BR>or<BR> int = quadg('Fun',xlow,xhigh,tol,trace,p1,p2,....)<BR><BR>This function works just like QUAD or QUAD8 but uses a Gaussian quadrature<BR>integration scheme. Use this routine instead of QUAD or QUAD8:<BR> if higher accuracy is desired (this works best if the function, <BR> 'Fun', can be approximated by a power series) <BR> or if many similar integrations are going to be done (I think less<BR> function evaluations will typically be done, but the <BR> integration points and the weights must be calculated.<BR> These are saved between integrations so when QUADG<BR> is called again, the points and weights are all ready<BR> known.)<BR> or if the function evaluations are time consuming.<BR>Note that if there are discontinuities the integral should be broken up into separate <BR>pieces. And if there are singularities, a more appropriate integration quadrature<BR>should be used (such as the Gauss-Chebyshev).<BR><BR>既然说了This function works just like QUAD or QUAD8 ，我想可以这样用吧<BR>f=quadg('sin(x)',1,2),可这样输入之后却：<BR><BR>??? Error: ()-indexing must appear last in an index expression.<BR>Error in ==> quadg at 56<BR>eval(exec_string);<BR><BR><BR>用quadc也出现同样的问题，请问各位高手这些函数到底怎么用啊，我看了帮助都说是和quad8,quad的用法一样啊，可使用quad8,quad就可以，用nit里面的函数就出错！晕倒！！请高手帮忙！谢谢先！！</P>
发表于 2006-4-10 16:47:45
>在网下载了matlab数值积分工具箱nit安装之后，看了一下里面的基本函数，然后想用其中几个试试看，比如先help quadg察看quadg函数的用法，帮助文件如下：<BR><BR>usage: int = quadg('Fun',xlow,xhigh)<BR>or<BR> int = quadg('Fun',xlow,xhigh,tol)<BR>or<BR> int = quadg('Fun',xlow,xhigh,tol,trace,p1,p2,....)<BR><BR>This function works just like QUAD or QUAD8 but uses a Gaussian quadrature<BR>integration scheme. Use this routine instead of QUAD or QUAD8:<BR> if higher accuracy is desired (this works best if the function, <BR> 'Fun', can be approximated by a power series) <BR> or if many similar integrations are going to be done (I think less<BR> function evaluations will typically be done, but the <BR> integration points and the weights must be calculated.<BR> These are saved between integrations so when QUADG<BR> is called again, the points and weights are all ready<BR> known.)<BR> or if the function evaluations are time consuming.<BR>Note that if there are discontinuities the integral should be broken up into separate <BR>pieces. And if there are singularities, a more appropriate integration quadrature<BR>should be used (such as the Gauss-Chebyshev).<BR><BR>既然说了This function works just like QUAD or QUAD8 ，我想可以这样用吧<BR>f=quadg('sin(x)',1,2),可这样输入之后却：<BR><BR>??? Error: ()-indexing must appear last in an index expression.<BR>Error in ==> quadg at 56<BR>eval(exec_string);<BR><BR><BR>用quadc也出现同样的问题，请问各位高手这些函数到底怎么用啊，我看了帮助都说是和quad8,quad的用法一样啊，可使用quad8,quad就可以，用nit里面的函数就出错！晕倒！！请高手帮忙！谢谢先！！</P>
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