Error during post alignment of cone beam data 2

when i use the following code for image reconstruction:

i=0;
proj_num =300; % number of used projections
step = 3000/proj_num;
% Preparing space for projections
% Coordinate order: column (u), angle, row (v)
projections = zeros(810,proj_num,2000);
ectors = zeros(numel(linspace(0,2pi,300)), 12);
for i = 1:numel(linspace(0,2
    pi,300))
    % source
    vectors(i,1) = sin(linspace(0,2*pi,300)) * 141.896514892578;
    vectors(i,2) = -cos(linspace(0,2*pi,300)) * 141.896514892578;
    vectors(i,3) = 0;
    
    % center of detector
    vectors(i,4) = -sin(linspace(0,2*pi,300)) * (871.5-141.896514892578);
    vectors(i,5) = cos(linspace(0,2*pi,300)) * (871.5-141.896514892578);
    vectors(i,6) = 0;
    
    % vector from detector pixel (0,0) to (0,1)
    vectors(i,7) = cos(linspace(0,2*pi,300)) * 0.2;
    vectors(i,8) = sin(linspace(0,2*pi,300)) * 0.2;
    vectors(i,9) = 0;
    
    % vector from detector pixel (0,0) to (1,0)
    vectors(i,10) = 0;
    vectors(i,11) = 0;
    vectors(i,12) = 0.2;
end

proj_geom = astra_create_proj_geom('cone_vec', 2000, 810, vectors);
factor(1) = 10;
factor(2) = 10;
proj_geom(:,4:6) = proj_geom(:,4:6) + factor(1) * proj_geom(:,7:9) + factor(2) * proj_geom(:,10:12);

The following error shows up;

Unable to perform assignment because the size of the left side is 1-by-1 and the size of the right side is 1-by-300.

Error in vector_code_samplerun (line 31)

vectors(i,1) = sin(linspace(0,2*pi,300)) * 141.896514892578;

Please assist

[Matt J]

The intention of the line,

vectors(i,1) = sin(linspace(0,2*pi,300)) * 141.896514892578;

is not clear. vector(i,1) is a scalar memory location. You cannot put a 1x300 vector there.

Answer 1

[yanqi liu]

sir，may be use cell to save data

and upload astra_create_proj_geom to do some analysis