Displaying 3 results from an estimated 3 matches for "lssum".
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2019 Jun 24
1
Calculation of e^{z^2/2} for a normal deviate z
..., both for your case and
the -- even more delicate -- case of e.g., alternating signs of
exponential terms.
"Unfortunately", we had never exported the functions from the
package, so you'd need
copula:::lsum() # log sum {of exponentials in log scale}
or
copula:::lssum() # log *s*igned sum {of exponentials in log scale}
for the 2nd case.
The advantage is it's simple R code implemented quite
efficiently for the vector and matrices cases,
Source code from source file copula/R/special-func.R
(in svn at R-forge :
-->
https://r-forge.r-project.org/s...
2013 Nov 07
1
R interface to C API Rf_logspace_{add,sub}?
Is there an R-language interface to the R API C-language functions Rf_logspace_add()
and Rf_logspace_sub()? I don't see one but I may not looking under the
right name.
Various packages have functions which do that same sort
of thing (log(exp(x)+exp(y)) and log(exp(x)-exp(y)) without unnecessary
floating point errors). They have names like
matrixStats::logSumExp(lx, na.rm=FALSE, ...)
2019 Jun 24
2
Calculation of e^{z^2/2} for a normal deviate z
>>>>> William Dunlap via R-devel
>>>>> on Sun, 23 Jun 2019 10:34:47 -0700 writes:
>>>>> William Dunlap via R-devel
>>>>> on Sun, 23 Jun 2019 10:34:47 -0700 writes:
> include/Rmath.h declares a set of 'logspace' functions for use at the C
> level. I don't think there are core R functions that call