How to resolve problem in for loop?
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a=java.math.BigInteger(100)
for i=1:a
a*a;
end
Undefined function '_colonobj' for input arguments of type 'java.math.BigInteger'.
Any help in this regard is much appreciated. Thanks
回答（1 个）
Is "a" a number, in the form MATLAB will expect it? NO! a is a BigInteger number. You cannot use the colon operator on a.
a=java.math.BigInteger(100)
whos a
So you could have used a loop like this:
for i = 1:double(a)
As far as the actual loop goes, What do you think this
a*a;
does? NOTHING. Well, it does something. It throws an error. Because again, multiplcation is NOT supported in MATLAB between java.math.BigInteger objects. And even if it was supported, it would do nothing useful in MATLAB, just dumping the result into the bit bucket.
Anyway, if you want to multiply BigInteger numbers, the Java toolbox provides such a tool. Admittedly, it is a bit of a pain in the neck. This is why I put my own wrapper around those tools for use in MATLAB.
4 个评论
Ammy
2021-12-11
Image Analyst
2021-12-11
编辑：Image Analyst
2021-12-11
@Ammy yes, but the value won't be saved because you didn't assign the product to any variable. So, because you left off the semicolon, it will print the value to the command window -- that's all. Maybe that's all you want - I don't know.
a=input('Enter a : ');
for k = 1 : a
result(k) = a * a;
end
result % Show all results in command window.
Lol. You are wasting your time.
Do you understand how big is that number?
log10(2589665665565686656656)
Over two sextillion.
Not much smaller than Avogadro's number. You want to loop THAT many times?
Are you running that loop on a super computer the size of the earth? Lets see. If you can run one billion loops per second, as I recall, there are roughly 31 million seconds in a year. So that will still take on the order of 85000 YEARS to finish the loop.
Are you a bit of an optimist? Or do you just have plenty of time to kill? Maybe you want to re-read the complete works of Shakespeare a few quadrillion times while you wait for it to finish?
Ammy
2021-12-11
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