The log1+ word uses flog1p and works well when numbers are small. The expm1 is provided as well, but not as a call the fexpm1:
https://docs.factorcode.org/content/word-e%5E-1%2Cmath.functions.html It’s a one line change to add fexpm1 plus tests to make sure it works if you’d like to make a contribution. Thanks, John. > On Jun 13, 2020, at 3:20 AM, SJain via Factor-talk > <factor-talk@lists.sourceforge.net> wrote: > > Dear Sir, > > Continuing about fexpm1 and flog1p, kindly note that in vocabulary > math.functions the definition of log1+ given as 1 + log, defeats the purpose > of giving flog1p in that 1 + log will always give inaccurate values when x > <<1. > > This definition of log1+ should be removed from the vocabulary math.functions > and flog1+ be retained in vocabulary math.libm. > > Similarly for expm1 function. > > Thanks and regards, > > SJain > Agra, India > > From: SJain <z...@ymail.com> > Sent: 13 June 2020 3:08:00 PM IST > To: LANG Factor <factor-talk@lists.sourceforge.net> > Subject: fexpm1 missing in math.libm > > Dear Sir, > > The function e^x - 1 , called fexpm1, is provided for in both C libm and x87 > instructions, just like it's counterpart log1p (ln(1+x)). While flog1+ is > provided in factor vocabulary math.libm, expm1 is missing. Both functions are > useful when x is small compared to 1. > > Kindly provide expm1 also. > > Thanks and regards, > > Sanjay Jain_______________________________________________ > Factor-talk mailing list > Factor-talk@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/factor-talk
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