Hi all,

Has anyone used the qua.regressCOP2 function from the copBasic package???
The default copula function used in this function is plackett copula and I
wanted to use archimedean copula. Attached below is my code:

mycop<-frankCopula
V=seq(0.001,0.99,by=0.000217)
R<-qua.regressCOP2(0.25,V,cop=mycop,para=c(3.504))

And this is the error I get:
Warning messages:
1: In qua.regressCOP2(0.25, V, cop = mycop, para = c(3.504)) :
  could not uniroot in derCOPinv2, skipping sample for i=4558 having
V=0.989869
2: In qua.regressCOP2(0.25, V, cop = mycop, para = c(3.504)) : 3.504


Would really appreciate if anyone could tell me what is causing the problem
and
how I should solve it.

indu

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