How to tabulate charge densities over 3D rectangular grid points

I would want to tabulate some charge densities over a 3d rectangular grid.

I created the attached file from reading multiple files and extracting their columns

of interest. I use the script below to read the attached text file

Path = 'Input correct path';
filename  = 'Input correct filename'
format='%5s%5s%5s%5.0f%8.3f%8.3f%8.3f%8.4f%8.4f%8.4f%[^\n\r]';
nAtoms = 52719;
fileID=fopen([path '/' filename]);
AllTraj=textscan...
    (fileID, format, nAtoms, 'Delimiter', '', 'WhiteSpace', '', 'EmptyValue' ,NaN,'HeaderLines', readstartrow, 'ReturnOnError', false);
fclose(fileID);
AllPositionsx = AllTraj{:,5}; % x
AllPositionsy = AllTraj{:,6}; % y
AllPositionsz = AllTraj{:,7}; % z
Charge = AllTraj{:,8}; % charge

The first 3 columns of (PostionPlusCharge) are the x,y,z postions respectively and the last column is the charge

I would want to tabulate the charges over a 3d rectangular grid based on x,y and z postions.

for instance for the first row x = 1.4810, y = 1.4760 and z= 7.7810. The corresponding charge is -0.6.

I want to do say, matrix(x,y,z) = -0.6.

I tried using

for k = 1:length(x)
    matrix(x(k),y(k),z(k)) = charge(k);
end

But the challenge is that, x,y and z are not integers.

[darova]

Maybe interp3 or griddata is what you are looking for?

[Anthony Owusu-Mensah]

I read the documentation. Seem not to be working for me. I used griddata and the resultant matrix has all NaN values

Answer 1

[darova]

Here is what i did

See attached script

[Anthony Owusu-Mensah]

Thanks Darova. Your solution has been an eye opener. I would extend it to all values of x, y and z. What was so informing is the use of the scatter3 to plot the scattered data.