hex2dec broken in R2020a?

Hi! We used to be able to do the following, at least up to R2019a:

>> hex2dec('ad55cb92eef08aea93f27c40457f8835')
ans =
     2.304019174741754e+38

Now we switched to R2020a, and I get:

>> hex2dec('ad55cb92eef08aea93f27c40457f8835')
Error using hex2dec
Hexadecimal text has too many digits for specified or implied type suffix.

...how can I achieve the old behavior?

Thanks in advance for any help!

P.S. In our particular application, we don't care about the precision of the conversion, as the hex input is actually a hash generated by DataHash(string).

[Jan]

Do you have a good reason to convert the hash to a decimal value? I cannot imagine how this could be useful. The has contains 128 bits, but a double value only 53.

Answer 1

[Jan]

hex2dec is much slower than sscanf(s, '%x'):

value = pow2([96, 64, 32, 0]) * sscanf(str, '%8x')

During the conversion to a double you reduce the precision from 128 to 53 bits. So it is enough to convert the first half:

value = pow2([96, 64]) * sscanf(str(1:16), '%8x')

Answer 2

[Stephen23]

format long
str = 'ad55cb92eef08aea93f27c40457f8835';
val = hex2dec(str(01:16))*pow2(64) + hex2dec(str(17:32))

Warning: Hexadecimal numbers representing integers greater than or equal to flintmax might not be represented exactly as double-precision floating-point values.

Warning: Hexadecimal numbers representing integers greater than or equal to flintmax might not be represented exactly as double-precision floating-point values.

val = 
     2.304019174741754e+38