MATLAB：曲线下的积分和阴影区域（无功能）

Question

我需要对两个已知 X 值之间的曲线下面积进行积分。索引值与实际的 x 值不对应（例如，3 秒处的数据点不在数组中的位置 3）。

我在尝试时意识到了这一点：

time=[0.1,1.5,2.1,3.2,4.5,6];
traceVect=[0,0.1,1,2,3.0,2.9];
hold on
plot(time,traceVect,'k');
t0=1;
td=5;
time = time(1,[t0:td]);
traceVect = traceVect(1,[t0:td]);
area(time,traceVect,'FaceColor','g');
a = trapz(time,traceVect);

这会产生情节：

为了清楚起见，我需要的是：

Answer 1

我的解决方案：

time=[0.1,1.5,2.1,3.2,4.5,6];
traceVect=[0,0.1,1,2,3.0,2.9];
hold on
plot(time,traceVect,'k');

%integration interval limits
t0=1;
td=5;

%select data points within the limits
ind = (time > t0) & (time < td);
xw = time(ind);
yw = traceVect(ind);

%then complete them by interpolation values at the edges
ya = interp1(time, traceVect, t0);
yb = interp1(time, traceVect, td);
xw = [t0, xw, td];
yw = [ya, yw, yb];

trapz(xw,yw)
area(xw,yw,'FaceColor','g');