Randi(imax,m,n)
조회 수: 6 (최근 30일)
이전 댓글 표시
How to increase the size of the argument imax in randi function. I used the code e=randi(phi,1,1) but there comes an error saying value of phi has to be less than 2^52. What to do to increase this range?
답변 (2개)
James Tursa
2020년 6월 17일
편집: James Tursa
2020년 6월 17일
The point is that once the eps of the max value is greater than 1, you cannot represent contiguous sets of integer values in double precision. E.g.,
>> eps(2^52)
ans =
1
>> eps(2^53)
ans =
2
So double precision could represent 2^52 + 1 exactly, but you see it will not be able to represent 2^53 + 1 exactly because eps(2^53) is greater than 1. So then the question becomes what makes sense for randi to produce as output when it can't represent all of the integers in the desired range? It doesn't make sense, hence the restriction.
댓글 수: 1
Matt J
2020년 6월 17일
Perhaps as follows,
num = uint64(randi(2^53-1,1))*2^8 +randi(2^8-1,1)
댓글 수: 2
James Tursa
2020년 6월 18일
편집: James Tursa
2020년 6월 18일
Using uint64 extends the allowed range beyond double, but of course it has a limit as well as you note. If you really need more range then use more than one variable for each value you need and extend Matt's approach.
참고 항목
카테고리
Help Center 및 File Exchange에서 Logical에 대해 자세히 알아보기
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!