在数组中每个元素之间使用MATLAB linspace [英] Using MATLAB linspace between every element in an array

问题描述

使用MATLAB，我想在数组的每个点之间进行线性插值.

Using MATLAB, I would like to linearly interpolate between every point in an array.

使用interpolate将以非线性方式进行.我想做的事情类似于产生低通滤波器系数.

Using interpolate will do it in a non-linear fashion. What I want to do is similar to producing low-pass filter coefficients.

我想出了一个解决方案，但我想避免使用for循环:

I have come up with a solution, but I would like to avoid using for loops:

a=[0 0 1 0 0]; %Input matrix
N=5; %Number of points to be added
b=[];
for i=1:length(a)-1
    b=[b linspace(a(i),a(i+1),N)];
end

有没有可能做到这一点?

Is it possible to do this without a loop?

推荐答案

您可以使用a中的点作为控制点来创建线性样条线.之后，您可以指定从开始间隔到结束间隔的任意多个点.就像Raab70所说的那样，您可以使用interp1.可以通过以下方式(使用linear插值)调用interp1:

You can create a linear spline with the points in a as control points. After that you can specify as many points as you want from a beginning interval to an ending interval. As what Raab70 said, you can use interp1. interp1 can be called in the following way (using linear interpolation):

out = interp1(x, y, xp, 'linear')

x是控制点的x值，y是控制点的y值. xp是要在其上评估功能的点.因为您没有明确地具有x值，而只想要y值，所以可以创建一个从1到L的虚拟矢量，其中L是输出数据中的点数.该伪向量用于您的x值.之后，将y指定为输出数据.在这种情况下，它是a的数组.接下来，您需要指定沿曲线采样的位置.因为要在每个空间之间引入5个点，所以总共总共有5 * 4 + 5 = 25个点.每个插槽" 5个点，并且总共有4个插槽.您还包括来自原始输出数据的5个点.要创建这25个点，只需在1到5之间执行linspace，然后指定在此间隔之间要25个点即可.这样可以完美地捕获控制点(1,2,3,4,5的虚拟值)以及要用于在每个控制点之间进行插值的值.

x are the x values and y are the y values for the control points. xp are the points you want to evaluate the function at. Because you don't explicitly have x values and you just want the y values, you can create a dummy vector that goes from 1 up to L where L is how many points are in your output data. This dummy vector is for your x values. After, specify y as your output data. In this case, it is the array of a. Next, you need to specify where you want to sample along the curve. Because you want to introduce 5 points in between each space, you will have in total 5*4 + 5 = 25 points all together. 5 points per "slot", and there are 4 slots all together. You also include the 5 points that were from your original output data. To create these 25 points, simply perform linspace from 1 up to 5 and specify that you want 25 points in between this interval. This should perfectly capture the control points (the dummy values of 1,2,3,4,5) as well as the values that you want to use to interpolate in between each of the control points.

这样，尝试这样的事情:

As such, try something like this:

N = 5; %// Number of points to introduce in between each control point
y = [0 0 1 0 0]; %// Your output data
L = numel(y); %// Size of output data. Cache so we don't have to keep typing in numel(y)
x = 1:L; %// Dummy vector
xp = linspace(1, L, N*(L-1) + N); %// Create points to interpolate. N*(L-1) + N is also just N*L
out = interp1(x, y, xp, 'linear'); %// Generate interpolated array

out因此给了我

out =

Columns 1 through 9

     0         0         0         0         0         0         0    0.1667    0.3333

Columns 10 through 18

0.5000    0.6667    0.8333    1.0000    0.8333    0.6667    0.5000    0.3333    0.1667

Columns 19 through 25

     0         0         0         0         0         0         0

这篇关于在数组中每个元素之间使用MATLAB linspace的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！