我正在尝试在x和y上绘制圆的方程式回归,但是我不知道如何进行。有什么建议么? (我想要一个圆通过最小二乘解连接点)
x = [5; 4; -1; 1];
y = [3; 5; 2; 1];
% circle's equation: x^2+y^2 = 2xc1+2yc2+c3
a = [2.*x,2.*y,ones(n,3)]
b = [x.^2 + y.^2];
c = a\b;
如何在此之后绘制圆
有两种方法可以在Matlab中绘制圆:
'o'
marker和'MarkerSize'
名称-值对设置圆的半径vscircle
function绘制圆形图像对于您而言,我会选择第一种方法,因为您可以控制圆的大小。rectangle(...,'Curvature',[1 1])
function[编辑:谢谢@Cris Luengo]所以这是绘图功能
function circle(x,y,r)
%x and y are the coordinates of the center of the circle
%r is the radius of the circle
%0.01 is the angle step, bigger values will draw the circle faster but
%you might notice imperfections (not very smooth)
ang=0:0.01:2*pi+.01;
xp=r*cos(ang);
yp=r*sin(ang);
plot(x+xp,y+yp);
end
因此,您的(更正的)代码看起来像这样
x = [5; 4; -1; 1];
y = [3; 5; 2; 1];
% circle's equation: x^2+y^2 = 2xc1+2yc2+c3
a = [2.*x,2.*y,ones(length(x),1)];
b = [x.^2 + y.^2];
c = a\b;
x_m = c(1)/2;
y_m = c(2)/2;
r = sqrt(x_m^2 + y_m^2 -c(3));
% plot data points
plot(x,y,'o')
hold on
% plot center
plot(x_m,y_m,'+')
% plot circle
circle(x_m,y_m,r)
hold off