Integer check with a symbolic variable
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So I have:
s=sym('10517669');
p=nextprime(8*(S^4));
if float((p-1)/2)==(p-1)/2
...
end
I know float only works for single&double-precision, but p is so large I have to use the symbolic toolbox because it don't want to lose precision.
How could I resolve this?
THANKS
2 个评论
Fangjun Jiang
2019-12-12
p is accurately represented using sym object in your code. You know p is an integer from theory. What do you try to do? double(p) or single(p) can't represent p without precision loss.
Yuechuan Chen
2019-12-12
编辑：Yuechuan Chen
2019-12-12
采纳的回答
更多回答（1 个）
Fangjun Jiang
2019-12-13
1 个投票
If you want to check whether (p-1)/2 is an integer, then check whether p is an odd number. But since p is a prime number, it seems p is always odd except that p==2.
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