How to use the small positive float number?

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Mahdiyar on 15 May 2015
Edited: Guillaume on 15 May 2015
Hi everyone
I am writing the code in which I need to deal with quite small number like
A = (1/2^8)^512
When I run this line, matlab gives back 0 as the results. However, I need this number to be multiplied with other big numbers.
How can I save the real value of variable A?
Many thanks,

Answers (1)

Guillaume on 15 May 2015
Edited: Guillaume on 15 May 2015
In plain matlab, you cannot represent such a number as it's way outside the range that a double can represent. The exponent part of a double is 11 bits, offset by 1023, so the minimum number that can be represented by a double is around 2^-1023 (the true minimum is 2^-1074), your number is 2^-4096!
You would have to use vpa from the Symbolic math toolbox (I know nothing about it, I don't have it), or go through Java's BigDecimal, or look through the file exchange for an arbitrary precision type.


Find more on Creating and Concatenating Matrices in Help Center and File Exchange

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