This function evaluates the second derivative of a given conditional parametric bivariate copula (h-function) with respect to its parameter(s) and/or its arguments.

BiCopHfuncDeriv2(
  u1,
  u2,
  family,
  par,
  par2 = 0,
  deriv = "par",
  obj = NULL,
  check.pars = TRUE
)

Arguments

u1, u2

numeric vectors of equal length with values in \([0,1]\).

family

integer; single number or vector of size length(u1); defines the bivariate copula family:
0 = independence copula
1 = Gaussian copula
2 = Student t copula (t-copula)
3 = Clayton copula
4 = Gumbel copula
5 = Frank copula
6 = Joe copula
13 = rotated Clayton copula (180 degrees; survival Clayton'') \cr `14` = rotated Gumbel copula (180 degrees; survival Gumbel'')
16 = rotated Joe copula (180 degrees; ``survival Joe'')
23 = rotated Clayton copula (90 degrees)
`24` = rotated Gumbel copula (90 degrees)
`26` = rotated Joe copula (90 degrees)
`33` = rotated Clayton copula (270 degrees)
`34` = rotated Gumbel copula (270 degrees)
`36` = rotated Joe copula (270 degrees)

par

numeric; single number or vector of size length(u1); copula parameter.

par2

integer; single number or vector of size length(u1); second parameter for the t-Copula; default is par2 = 0, should be an positive integer for the Students's t copula family = 2.

deriv

Derivative argument
"par" = second derivative with respect to the first parameter (default)
"par2" = second derivative with respect to the second parameter (only available for the t-copula)
"u2" = second derivative with respect to the second argument u2
"par1par2" = second derivative with respect to the first and second parameter (only available for the t-copula)
"par1u2" = second derivative with respect to the first parameter and the second argument
"par2u2" = second derivative with respect to the second parameter and the second argument (only available for the t-copula)

obj

BiCop object containing the family and parameter specification.

check.pars

logical; default is TRUE; if FALSE, checks for family/parameter-consistency are omitted (should only be used with care).

Value

A numeric vector of the second-order conditional bivariate copula derivative

  • of the copula family

  • with parameter(s) par, par2

  • with respect to deriv

  • evaluated at u1 and u2.

Details

If the family and parameter specification is stored in a BiCop() object obj, the alternative version

BiCopHfuncDeriv2(u1, u2, obj, deriv = "par")

can be used.

References

Schepsmeier, U. and J. Stoeber (2014). Derivatives and Fisher information of bivariate copulas. Statistical Papers, 55 (2), 525-542.
https://link.springer.com/article/10.1007/s00362-013-0498-x.

Author

Ulf Schepsmeier, Jakob Stoeber

Examples


## simulate from a bivariate Student-t copula
set.seed(123)
cop <- BiCop(family = 2, par = -0.7, par2 = 4)
simdata <- BiCopSim(100, cop)

## second derivative of the conditional bivariate t-copula
## with respect to the first parameter
u1 <- simdata[,1]
u2 <- simdata[,2]
BiCopHfuncDeriv2(u1, u2, cop, deriv = "par")
#>   [1]  1.684670085  1.445009072 -2.394632254  0.982319498 -0.191463014
#>   [6]  0.660424888  0.971719208  2.440708983  0.214286898  0.735750053
#>  [11]  0.865859546 -0.826942333  1.371145360  0.840860772 -0.776475632
#>  [16]  0.008169539  1.150068878 -0.680998756 -1.634456821 -1.263989302
#>  [21] -1.053239868 -1.135876455 -0.347449083 -0.904761438  1.937043020
#>  [26] -0.780754028 -2.103406988 -1.626156073  1.152225034  0.164024046
#>  [31] -1.515278923 -1.415894639  0.498752417  0.717053922  0.390384267
#>  [36]  1.210797867  1.396122934 -1.520793273  0.552033413 -0.665179440
#>  [41]  0.637576307  1.639953393 -0.963797893  0.006389292 -1.892352512
#>  [46]  0.145683737  0.814594480 -1.104411804 -1.968056324 -0.010296275
#>  [51] -1.028464408  0.195577283  1.145021627  0.910886652 -1.122746697
#>  [56] -0.345564403  2.498135976 -1.907495873  0.061917278 -0.511336603
#>  [61] -1.022735637 -1.203236461 -0.410064338 -0.088728755  0.533887346
#>  [66]  0.721896034  1.340647857  1.194188493  0.800877461  0.581664953
#>  [71] -1.071688265 -0.068227240 -1.389045448 -0.099737516  1.224448034
#>  [76]  0.820782305 -1.417771175 -0.992658620 -1.622962530 -1.474726157
#>  [81] -1.078873722 -0.570379523 -0.173455058 -1.614146320 -1.445734562
#>  [86] -1.728832154  0.806776801  1.166384415 -0.153542873  1.020935552
#>  [91] -0.569062496 -1.330198030  0.140860267 -0.194946931  0.045410090
#>  [96] -1.286555025  0.474808114  0.718238125  0.985394505 -0.428647857

## estimate a Student-t copula for the simulated data
cop <- BiCopEst(u1, u2, family = 2)
## and evaluate the derivative of the conditional copula
## w.r.t. the second argument u2
BiCopHfuncDeriv2(u1, u2, cop, deriv = "u2")
#>   [1]    3.6804067   -0.7689591 -546.2427458   -1.7753555   -0.5376870
#>   [6]  -40.2486651   -2.6000245   83.9006421    0.7824081    0.8735943
#>  [11]   -3.9165914   -0.4304624   -2.2060138   -0.9712828    1.7545863
#>  [16]   -0.2570602   -2.0714937   47.8458348   -6.5611891    2.1651901
#>  [21]    5.8160920    1.5737490    1.2067824    4.2801871    5.0373857
#>  [26]   18.1839777  -13.7328026    0.5702948   24.6636973  -19.7344966
#>  [31]   -0.9175689    1.9495009   -7.0195978   -1.8495088   -6.1955126
#>  [36]   -3.3205444 -235.4306035    1.4216690    1.3931585    1.7178143
#>  [41]    5.5380198   -0.2032016    8.3320801   -0.2110902  -42.7264285
#>  [46]   16.0566221    2.0317966    1.9937195  -11.6912382    0.4111560
#>  [51]   -0.7876488   -1.8724216   -1.5927369   -7.5474007    1.8406191
#>  [56]  -57.8832126  465.5573090   -4.0717211   -1.7857176   -0.8468740
#>  [61]   -1.7472930    2.1395192    0.1429259    0.7623111   16.1019173
#>  [66]   -1.7703424   -2.2350047   -0.9425511   -2.1128965 -122.0992576
#>  [71]    2.7097746    1.9718369  -17.4871714    1.0457833    5.8769918
#>  [76]   -7.6414720    1.9291341    6.2310307    0.3409169    1.6421899
#>  [81]    0.5994465   -1.9659926    2.0526910   -5.2473112    1.7672025
#>  [86]   -0.5800653   -2.6701584   -2.4332835    1.7713090   -6.5459479
#>  [91]  -12.9850109   -3.5315516   -1.2703370    4.1082368   -0.4988247
#>  [96]    2.7557713  -34.9362417  -23.6304023    0.7004355    9.7279802