清空筛选条件
清空筛选条件

how can I get rid of these errors?

1 次查看（过去 30 天）
frwmetric
frwmetric 2013-5-28
hi I have a huge function to integrate
>> syms x y
>> f=(228155022448185.*(cos((2.*pi).*y)./exp(131738205584307./(35184372088832.*x)) - 1)*(cos((8.*pi).*y)/exp(131738205584307./(8796093022208.*x)) - 1)*(cos((8.*pi).*y)/exp(131738205584307./(8796093022208.*x)) + cos((18.*pi).*y)/exp(1185643850258763./(35184372088832.*x)) - 2))/((18014398509481984.*(x.^2)).*exp(x.*((1981232555272083.*(y.^2))/2251799813685248 - y./16 + 1./16)))
I need integration of it( x:[0,inf) and y:[0,1] )
but for this function I receive error for quad2d and dblquad
quad2d(quadfun,0,100,0,1)
??? Error using ==> quad2d>tensor at 350
Integrand output size does not match the input size.
Error in ==> quad2d at 164
[Qsub,esub] = tensor(thetaL,thetaR,phiB,phiT);
and
dblquad(quadfun,0,100,0,1)
??? Error using ==> dblquad>innerintegral at 74
Inputs must be floats, namely single or double.
Error in ==> quad at 76
y = f(x, varargin{:});
Error in ==> dblquad at 53
Q = quadf(@innerintegral, ymin, ymax, tol, trace, intfcn, ...
could you explain why these errors appear? and how can I fix it?

请先登录，再回答此问题。

回答（1 个）

Roger Stafford
Roger Stafford 2013-5-28
The 'quad2d' and 'dblquad' functions are intended for use with numerical data, namely 'double' or 'single' variables as the error message has stated. For integration with symbolic variables you should be using the 'int' function - in this case you need an 'int' of an 'int' to accomplish double integration. Either that or switch to 'double' type for x and y. (In the latter case you may encounter numerical difficulties with the x variable ranging from zero to infinity within the exponential function.)

类别

在 Help Center 和 File Exchange 中查找有关 Polynomials 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by