Problem with if function and decimal numers
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Good evening, i have a problem with this code:
a=1:0.1:2;
b=0.1;
for i=1:1:10
angoloutile(i)=a(i);
end
for j=1:1:10
integ = fix(angoloutile(j)) ;
fract = abs(angoloutile(j)- integ);
if fract == b
angoloutile(j)=angoloutile(j)+0.5
end
end
for k=1:1:10
angoloutile(k)
end
it doesn't take the IF function
if fract == b
but i'm sure that angoloutile(2) is 1.1 Thanks
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Image Analyst
il 13 Gen 2014
The problem was using fix instead of rounding. Try this where I use int32() to cast to the nearest integer. I also cleaned up your if to make it more efficient and reduce the number of if tests by a factor of 10.
a=1:0.1:2;
for i=1:1:10
angoloutile(i)=a(i);
end
for j=1:1:10
integ = fix(angoloutile(j));
fract = abs(angoloutile(j)- integ);
fract=fract*10;
deci=int32(fract);
fprintf('j = %d, angoloutile(j) = %f, integ = %d, fact = %f, deci = %d\n', ...
j, angoloutile(j), integ, fract, deci);
if deci == 1
angoloutile(j)=angoloutile(j)+0.5;
elseif deci == 2
angoloutile(j)=angoloutile(j)-0.08;
elseif deci == 3
angoloutile(j)=angoloutile(j)-0.12;
elseif deci == 4
angoloutile(j)=angoloutile(j)-0.16;
elseif deci == 5
angoloutile(j)=angoloutile(j)-0.20;
elseif deci == 6
angoloutile(j)=angoloutile(j)-0.24;
elseif deci == 7
angoloutile(j)=angoloutile(j)-0.28;
elseif deci == 8
angoloutile(j)=angoloutile(j)-0.32;
elseif deci == 9
angoloutile(j)=angoloutile(j)-0.36;
end
end
% Print to command window.
angoloutile
Più risposte (1)
Amit
il 13 Gen 2014
The issue is very small difference in floating point numbers, like 1.00000 and 1.0000000001. There is negligible difference however they are not equal. You can do something like:
tol = 1e-6;
if (fract-b) < tol
This will work.
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