Creating a matrix for each point point in a data set

Question

Jeff C. 2015-2-21

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/179598-creating-a-matrix-for-each-point-point-in-a-data-set

评论： Sad Grad Student 2015-2-21

I am trying to create a new matrix for each point in a large dataset, but I am not sure how I can do this without writing out each one. From this dataset I have created an origin and three vectors for each point, and I need to put the origin and three vectors into a 4x4 identity matrix. Is there a way to do this using for loops?

2 个评论
显示无隐藏无

Sad Grad Student 2015-2-21

Can you give an example of what you want?

Jeff C. 2015-2-21

So I have a data set of 806 points and I have created 806 origins, x vectors, y vectors, and z vectors. I need a 4x4 matrix that would look like (1,0,0,0;o1,x1,x2,x3;o2,y1,y2,y3;o3,z1,z2,z3) for each of the 806 data points. I hope that helps.

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Sad Grad Student 2015-2-21

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/179598-creating-a-matrix-for-each-point-point-in-a-data-set#answer_168808

在 MATLAB Online 中打开

M = {}; % creating a cell array that will contain your 806 matrices
 for i = 1:806
    M{i} = eye(4,4);
    M{i}(2:end,1) = o; % your vector of origins. o = [o1 o2 o3]
    M{i}(2:end,2) = x; % your x vector. x = [x1 x2 x3]
    M{i}(2:end,3) = y; % your y vector. y = [y1 y2 y3]
    M{i}(2:end,4) = z; % your z vector. z = [z1 z2 z3]
  end

2 个评论
显示无隐藏无

Jeff C. 2015-2-21

I tried this but it told me there was an error with dimension size, so I changed it to: for i = 1:806 M{i} = eye(4,4); M{i}(2:end,1) = o(i,:); % your vector of origins. o = [o1 o2 o3] M{i}(2:end,2) = x(i,:); % your x vector. x = [x1 x2 x3] M{i}(2:end,3) = y(i,:); % your y vector. y = [y1 y2 y3] M{i}(2:end,4) = z(i,:); % your z vector. z = [z1 z2 z3] end

The code runs without error now, however if I try to call the 200th matrix, using a=M(200) it just returns a=[4x4 double]. Not sure what is wrong there.

Thanks so much for your help by the way.

Sad Grad Student 2015-2-21