How to make array in matlab ( how to inisialisasi array )

how to use array in matlab

Answer 1

[Oleg Komarov]

Preallocation of an array is usually done with the zeros function:

B = zeros(n)
B = zeros(m,n)
B = zeros([m n])
B = zeros(m,n,p,...) 
B = zeros([m n p ...])

where m,n,p,... express the size for the 1st,2nd,3rd,...nth dimension.

If you're not looking for preallocation then your answer is too generic.

Something else I can think of is a generation of a random matrix, see rand and related functions.

All of the basic are well covered, wiht many examples in the getting started guide

EDIT

obj=VideoReader(video);
% (start)
%akhir deklarasi gambar yang ada di axes

numFrames = obj.NumberOfFrames;
waktu     = obj.Duration;
iterasi   = numFrames/waktu;
vidHeight = obj.Height;
vidWidth  = obj.Width;
disp(numFrames);
a = length(numFrames);

frames = zeros(vidHeight,vidWidth,iterasi);
c = 0;
if(~isempty(get(handles.nmvideo,'String')))
    try
        for n = 1:iterasi:numFrames
            c = c+1;
            frames(:,:,c) = read(obj,n);
            h = axes(handles.axes1);
            imshow(frames(:,:,c));
        end
    catch
        msgbox('Codec AVI tidak didukung atau Corupted file AVI','Error','error');
        return
    end
else
    msgbox('Anda harus memilih video terlebih dahulu','Error','error');
end

[Megah Putri]

thx oleg komarov, i have problem about my program... maybe can you help me, i want to make array for inisialisasi frame 1 until frame 32 .... this is my code, maybe you can fix it ... :

obj=VideoReader(video);

% (start)

global frame1;global frame2;global frame3;global frame4;global frame5;

global frame6;global frame7;global frame8;global frame9;global frame10;

global frame11;global frame12;global frame13;global frame14;global frame15;

global frame16;global frame17;global frame18;global frame19;global frame20;

global frame21;global frame22;global frame23;global frame24;global frame25;

global frame26;global frame27;global frame28;global frame29;global frame30;

global frame31;global frame32;

%akhir deklarasi gambar yang ada di axes

numFrames=obj.NumberOfFrames;

waktu=obj.Duration;

iterasi=numFrames/waktu;

vidHeight = obj.Height;

vidWidth = obj.Width;

disp(numFrames);

a=length(numFrames);

disp(a);

if(~isempty(get(handles.nmvideo,'String')))

try

for n = 1:iterasi:numFrames

frame1=read(obj,n);

axes(handles.axes1);

imshow(frame1);

end

,enam);

catch

msgbox('Codec AVI tidak didukung atau Corupted file AVI','Error','error');

return;

end

else

msgbox('Anda harus memilih video terlebih dahulu','Error','error');

end

[Oleg Komarov]

Please post the correct code in your original message and format it with the {} button.

,enam);

Is definitely an uncomplete line.

[Oleg Komarov]

Drop the global part, then preallocate:

frames = zeros(vidHeight,vidWidth,iterasi);

c = 0;

Inside the loop

c = c+1;

frame(:,:,c) = read(...)

[Megah Putri]

oleg komarov, i have question , in "frames = zeros(vidHeight,vidWidth,iterasi); " ... is it frames or frame? why in the behind oh your code is frame not frames? ( "frame(:,:,c) = read(...)")... and if i want to display the object, " imshow () " what? imshow (frame) ? or imshow (frames) ?

[Oleg Komarov]

Sorry just a typo. Call it however you like it, it's the same array.

To display:

imshow(frames(:,:,c))

[Megah Putri]

hhhmmm oleg komarov... i had try it,,, but i can't ... :( ... maybe i must study hard for understand it ...

[Megah Putri]

frames its a variable, oleg ?

[Oleg Komarov]

See my edit, post error messages and|or unexpected behaviour.

[Megah Putri]

hhhhhmmmmmmmmmmmm...............

[Walter Roberson]

Yes, frames is a variable.