value transform by for loop

clear all;clc;

n=5;

for i= 1:n

c(:,:,i)=randi([0 3], 2, 2);

end

for i= 1:n

cdct(:,:,i) = dct2(c(:,:,i));

end

cd1_1 = cdct(1,1,:);

lcd1_1 = cd1_1(:);

for j=1:5

if lcd1_1(j) == 0

lcd1_1(j) = 10;

elseif lcd1_1(j) == 0.5

lcd1_1(j) = 20;

elseif lcd1_1(j) == 1

lcd1_1(j) = 30;

elseif lcd1_1(j) == 1.5

lcd1_1(j) = 40;

elseif lcd1_1(j) == 2

lcd1_1(j) = 50;

elseif lcd1_1(j) == 2.5

lcd1_1(j) = 60;

elseif lcd1_1(j) == 3

lcd1_1(j) = 70;

elseif lcd1_1(j) == 3.5

lcd1_1(j) = 80;

elseif lcd1_1(j) == 4

lcd1_1(j) = 90;

end

end

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

above is my code my goal is transform lcd1_1

if lcd1_1 was zero then transfer it to ten

if lcd1_1 was 0.5 then transfer it to twenty

step bt step to transfer all my lcd1_1 values

why my for loop not work please help me thanks

Answer 1

[Torsten]

Floating point arithmetic. To check for equality (==) always gives problems.

Take a look at

https://de.mathworks.com/help/matlab/ref/ismembertol.html

clear all;clc;
n=5;
for i= 1:n
    c(:,:,i)=randi([0 3], 2, 2);
end
for i= 1:n
    cdct(:,:,i) = dct2(c(:,:,i));
end
cd1_1 = cdct(1,1,:);
lcd1_1 = cd1_1(:);
for j = 1:5
  v(j) = lcd1_1(j)==0|lcd1_1(j)==0.5|lcd1_1(j)==1|lcd1_1(j)==1.5|lcd1_1(j)==2|lcd1_1(j)==2.5|lcd1_1(j)==3|lcd1_1(j)==3.5|lcd1_1(j)==4;
end
v
for j=1:5
    if  lcd1_1(j) == 0
        lcd1_1(j) = 10;
    elseif  lcd1_1(j) == 0.5
        lcd1_1(j) = 20;
    elseif  lcd1_1(j) == 1
        lcd1_1(j) = 30;
    elseif  lcd1_1(j) == 1.5
        lcd1_1(j) = 40;
    elseif  lcd1_1(j) == 2
        lcd1_1(j) = 50;
    elseif  lcd1_1(j) == 2.5
        lcd1_1(j) = 60;
    elseif  lcd1_1(j) == 3
        lcd1_1(j) = 70;
    elseif  lcd1_1(j) == 3.5
        lcd1_1(j) = 80;
    elseif  lcd1_1(j) == 4
        lcd1_1(j) = 90;
    end
end 
lcd1_1