How can I convert Matlab Integer into java.math.BigInteger
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i want to use RSA algorithm to demonstrate the simple key generation in matlab (step by step); and i use GUI to pass the data.
the problem is when i using java.math.BigInteger;
i found that java.math.BigInteger needs char to calculate the modPow, modInvers, etc.
so when my input is an integer, i convert to string use "num2str", it works.
mycode:
a=23423423423454
b=num2str(a)
c=java.math.BigInteger(b)
but when i use larger number, it goes to error.
mycode:
a=999999999999999999
b=num2str(a)
c=java.math.BigInteger(b)
so i have to write manuual
mycode:
a='999999999999999999'
b=java.math.BigInteger(a)
is there a function to do it automatic without errorr??? i am newbie to Matlab
2 Comments
Friedrich
on 20 May 2014
Why do you want to use BigInteger in the first place? Why don't you do the calculation completly in MATLAB?
Accepted Answer
Friedrich
on 20 May 2014
When using that big numbers use uint64 instead of doubles. This will also help in calling java.math.BigInteger, e.g.
>>a=uint64(999999999999999999)
>>c=java.math.BigInteger(num2str(a))
When using double values you have loss of precission, e.g.
>> a=999999999999999999;
>> sprintf('%16.0f',a)
ans =
1000000000000000000
>>
2 Comments
Friedrich
on 21 May 2014
>> bigint = sym('999999999999999999')^10000;
>> mod(bigint,32)
ans =
1
So you can do you complete calculation using symbolic math.
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