Displaying 3 results from an estimated 3 matches for "qbeta0".
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2020 Mar 26
4
unstable corner of parameter space for qbeta?
...'t seem to be in a particularly extreme corner of
parameter space. It happens, e.g., for these parameters:
phi <- 1.1
i <- 0.01
t <- 0.001
shape1 = i/phi ## 0.009090909
shape2 = (1-i)/phi ## 0.9
qbeta(t,shape1,shape2) ## 5.562685e-309
## brute-force uniroot() version, see below
Qbeta0(t,shape1,shape2) ## 0.9262824
The qbeta code is pretty scary to read: the warning "full precision
may not have been achieved" is triggered here:
https://github.com/wch/r-source/blob/f8d4d7d48051860cc695b99db9be9cf439aee743/src/nmath/qbeta.c#L530
Any thoughts? Should I report this...
2020 Mar 26
0
unstable corner of parameter space for qbeta?
...t happens, e.g., for these parameters:
> phi <- 1.1
> i <- 0.01
> t <- 0.001
> shape1 = i/phi ## 0.009090909
> shape2 = (1-i)/phi ## 0.9
> qbeta(t,shape1,shape2) ## 5.562685e-309
> ## brute-force uniroot() version, see below
> Qbeta0(t,shape1,shape2) ## 0.9262824
> The qbeta code is pretty scary to read: the warning "full precision
> may not have been achieved" is triggered here:
> https://github.com/wch/r-source/blob/f8d4d7d48051860cc695b99db9be9cf439aee743/src/nmath/qbeta.c#L530
> Any...
2020 Mar 26
2
unstable corner of parameter space for qbeta?
...> > phi <- 1.1
> > i <- 0.01
> > t <- 0.001
> > shape1 = i/phi ## 0.009090909
> > shape2 = (1-i)/phi ## 0.9
> > qbeta(t,shape1,shape2) ## 5.562685e-309
> > ## brute-force uniroot() version, see below
> > Qbeta0(t,shape1,shape2) ## 0.9262824
>
> > The qbeta code is pretty scary to read: the warning "full precision
> > may not have been achieved" is triggered here:
>
> > https://github.com/wch/r-source/blob/f8d4d7d48051860cc695b99db9be9cf439aee743/src/nmath/q...