what does thegrid{1}.points=(1:n); mean?

Hello. I don't understand the underlined part. Can you please explain what is it doing?

thegrid=cell(1);

thegrid{1}.coordinate=zeros(p,1);

thegrid{1}.points=(1:n);

[Walter Roberson]

Could you clarify what this has to do with python (that you tagged with) ?

Answer 1

[Dave B]

Cell arrays are containers for heterogenous data, each cell can hold arbitrary types/sizes/shapes. Cells are addressed with { }

The code creates a scalar cell array called grid

In the first (and only) cell in the grid, the code implicitly creates a struct. Structs are also containers that hold heterogenous data, but instead of indexing them by rows and columns it uses named fields. thegrid{1} has two fields: coordinate and points.

Inside thegrid{1}.coordinate theres a column of p zeros

Inside thegrid{1}.points are integers between 1 and n

Hope that helps, please let me know if you have more specific questions!

Cell arrays: https://www.mathworks.com/help/matlab/cell-arrays.html

Structs: https://www.mathworks.com/help/matlab/structures.html

[Ronak]

It was so helpful. Thank you so much.

[Ronak]

Hi. This is a part of the code that I wrote earlier. Can you please explain what is it doing here (Bold lines)? As far as I know it must remove gridpoints from thegrid and partitions gridpoints with a probability (prob). But I don't understand how it is doing the removing and patirioning.

for j=1:L

gridpoints=[gridpoints,thegrid{j}.coordinate];

npoints=length(thegrid{j}.points);

directions_numeric=sign(X_data(:,thegrid{j}.points)-thegrid{j}.coordinate*ones(1,npoints));

directions=num2cell(num2str(directions_numeric'),2);

numericmap=containers.Map(directions,num2cell(directions_numeric,1));

cubemap=containers.Map(directions,cell(npoints,1));

for i=1:npoints

cubemap(directions{i})=[cubemap(directions{i}),i];

end;

keyset=keys(cubemap);

valset=values(cubemap);

for i=1:length(cubemap)

activesize=length(valset{i});

if(activesize>gamma)

prob=1-0.5*exp(-epss*(activesize-gamma));

else

prob=0.5*exp(epss*(activesize-gamma));

end;

if(random('bino',1,prob)>0.5)

tempobj.coordinate=thegrid{j}.coordinate+side_length/2*numericmap(keyset{i});

tempobj.points=valset{i};

newgrid=[newgrid,tempobj];

end;

end;

[Dave B]

there are a lot of little expressions in there, can you clarify which part is confusing? A good tip in MATLAB is: start with one set of values (i.e. get out of the loop by setting i and j to be 1). break the code out into its statements (i.e. take each function one at a time), run them in the command window with no semicolon so you can see what the output is.