[PD] problem with correct numbers in pd double precision

hans w. koch hansw.koch at gmail.com
Fri Sep 18 23:12:21 CEST 2020


its probably due to my lack of understanding the correct number representations, but here it goes anyway:

i compiled pd 51-2 double precision for mac 10.14.6
with this version i was hoping to do some maths on big numbers.
but already an increment of 1 on some moderatly big number gives me problems of representation.

i made a simple version of the problem as a patch.
to verify you have a working version of pd double, it contains a simple test.
and then an iterative addition +1 starting from 999999.
i get this:
count: 999999
count: 1e+06
count: 1e+06
count: 1e+06
count: 1e+06
count: 1e+06
count: 1.00000e+06
count: 1.00001e+06
count: 1.00001e+06
count: 1.00001e+06

the algorith terminates succesfully by a [select] after 10 iterations, but the results don´t show what i expect.
this to me indicates, that the internal numbers are correct, but they don´t “surface” as such.

i would be grateful for any pointers and possible workarounds, as the numbers i hope to be dealing with are potentially orders of magnitude higher.

thanks hans

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