How to improve double precision?

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NoYeah
NoYeah on 23 Jul 2020
Edited: Stephen23 on 25 Jul 2020
I have made below code
a=11;
b=256;
c=a/b
and the output said c=0, which was not I had expected
So I have used cast operator
a=11;
b=256;
c=double(a/b)
and the result returns the same value; 0
I have searched Matlab document and found that the default precision of double data type is 32
so It should return 0.04296875 instead of 0. But still get 0 for this kind of codes
How to fix it properly?
  4 Comments
dpb
dpb on 23 Jul 2020
I asked you to type in teh above commands on your system and tell us what you get?
Stephen23
Stephen23 on 23 Jul 2020
Edited: Stephen23 on 25 Jul 2020
"I have searched Matlab document and found that the default precision of double data type is 32"
Highly unlikely. Can you please provide a link to the MATLAB documentation where this value comes from?

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Accepted Answer

Walter Roberson
Walter Roberson on 23 Jul 2020
Either your a or your b is type uint8. When you work with int8, int16, int32, uint8, uint16, or uint32, then the operands are converted to double(), and the operation is done, and then the result is converted back to the most restricted type used.
Operations for int64 and uint64 are handled differently in some, because 64 bit integers cannot be converted to double without losing precision.
  1 Comment
dpb
dpb on 23 Jul 2020
Edited: dpb on 23 Jul 2020
Could be any of the int classes, of course...what the
whos a b c
would have told us is which one(s) OP had...what OP didn't show was how a, b were created to begin with to become int class

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