作者zupo (外派越南工作者)
标题Re: [绘图] 联立不等式绘图
时间Mon Dec 9 22:42:21 2013
※ 引述《JeremyKSKGA (GIANTS!!!)》之铭言：
: 从来没做过联立不等式绘图...囧
: 譬如我想做以下的联立不等式
: 2 x^2 + 4 y^2 - 4 x^2 * y^2 < 1
: 1 - x^2 - 2 y^2 > 0
: 请问我该如何求出x对y作图
: 以及指令求出x和y的最大值??
利用fmincon函数求解
------------------------------------------------------
function pttex140
% 解法
[xy target] = fmincon(@obj,[0;0],[],[],[],[],[],[],@myfun);
x = xy(1)
y = xy(2)
maxfun = target*(-1)
% 验算
%
a = 2.*x.^2 + 4.*y.^2 - 4.*(x.^2).*(y.^2)-1
b = x.^2 + 2.*y.^2 -1
function [f,feq] = myfun(x)
f(1) = 2.*x(1).^2 + 4.*x(2).^2 - 4.*(x(1).^2).*(x(2).^2)-1;
f(2) = x(1).^2 + 2.*x(2).^2 -1;
feq = [];
function f = obj(x)
f = -x(1)-x(2);
-------------------------------------------------------------
Active inequalities (to within options.TolCon = 1e-06):
lower upper ineqlin ineqnonlin
1
x =
0.5880
y =
0.3434
maxfun =
0.9313
a =
4.2277e-10
b =
-0.4185
先看看. 有问题再讨论.
另外绘图的部分就自己叠代後绘图
这边不着墨太多
--
1.MATLAB programming 2.ASPEN process simulation package
3.FORTRN programming 4.Advance Engineering Mathematics
5.Process Control Theory
6.Chemical Engineering Basic Theory(Kinetic.thermodynamics.transport)
7.Numerical Method and Analysis
8.MATLAB Toolbox.Simulink system basic design
--
※ 发信站: 批踢踢实业坊(ptt.cc)
◆ From: 113.186.203.142