sbpsi function

Model Specification Functions

Model Specification Functions

sbpsi.poly and sbpsi.sing are ψ\psi functions to specify a polynomial model and a singular model, respectively.

sbpsi.poly(beta,s=1,k=1,sp=-1,lambda=NULL,aux=NULL,check=FALSE) sbpsi.sing(beta,s=1,k=1,sp=-1,lambda=NULL,aux=NULL,check=FALSE) sbpsi.sphe(beta,s=1,k=1,sp=-1,lambda=NULL,aux=NULL,check=FALSE) sbpsi.generic(beta,s=1,k=1,sp=-1,lambda=NULL,aux=NULL,check=FALSE,zfun,eps=0.01) sbmodelnames(m=1:3,one.sided=TRUE,two.sided=FALSE,rev.sided=FALSE, poly,sing,poa,pob,poc,pod,sia,sib,sic,sid,sphe,pom,sim)

Arguments

  • beta: numeric vector of parameters; β0\beta_0=beta[1], β1\beta_1=beta[2],... βm1\beta_{m-1}=beta[m], where mm is the number of parameters.
  • s: σ02\sigma_0^2.
  • k: numeric to specify the order of derivatives.
  • sp: σp2\sigma_p^2.
  • lambda: a numeric of specifying the type of p-values; Bayesian (lambda=0) Frequentist (lambda=1).
  • aux: auxiliary parameter. Currently not used.
  • check: logical for boundary check.
  • zfun: z-value function with (s,beta) as parameters.
  • eps: delta for numerical computation of derivatives.
  • m: numeric vector to specify the numbers of parameters.
  • one.sided: logical to include poly and sing models.
  • two.sided: logical to include poa and sia models.
  • rev.sided: logical to include pob and sib models.
  • poly: maximum number of parameters in poly models.
  • sing: maximum number of parameters in sing models.
  • sphe: maximum number of parameters in sphe models.
  • poa: maximum number of parameters in poa models.
  • pob: maximum number of parameters in pob models.
  • poc: maximum number of parameters in poc models.
  • pod: maximum number of parameters in pod models.
  • sia: maximum number of parameters in sia models.
  • sib: maximum number of parameters in sib models.
  • sic: maximum number of parameters in sic models.
  • sid: maximum number of parameters in sid models.
  • pom: maximum number of parameters in pom models.
  • sim: maximum number of parameters in sim models.

Details

For k=1k=1, the sbpsi functions return their ψ\psi function values at σ2=σ02\sigma^2=\sigma_0^2. Currently, four types of sbpsi functions are implemented. sbpsi.poly defines the polynomial model;

ψ(σ2β)=j=0m1βjσ2j \psi(\sigma^2 | \beta) =\sum_{j=0}^{m-1} \beta_j \sigma^{2j}

for m1m\ge1. sbpsi.sing defines the singular model;

ψ(σ2β)=β0+j=1m2βjσ2j1+βm1(σ1) \psi(\sigma^2 | \beta) = \beta_0 +\sum_{j=1}^{m-2} \frac{\beta_j \sigma^{2j}}{1 + \beta_{m-1}(\sigma-1)}

for m3m\ge3 and 0βm110\le\beta_{m-1}\le1. sbpsi.sphe defines the spherical model; currently the number of parameters must be m=3m=3. sbpsi.generic is a generic sbpsi function for specified zfun.

For k>1k>1, the sbpsi functions return values extrapolated at σ2=σp2\sigma^2=\sigma_p^2 using derivatives up to order k1k-1

evaluated at σ2=σ02\sigma^2=\sigma_0^2;

qk=j=0k1(σp2σ02)jj!djψ(xβ)dxjσ02, q_k = \sum_{j=0}^{k-1} \frac{(\sigma_p^2-\sigma_0^2)^j}{j!}\frac{d^j \psi(x|\beta)}{d x^j}\Bigr|_{\sigma_0^2},

which reduces to ψ(σ02β)\psi(\sigma_0^2|\beta) for k=1k=1. In the summary.scaleboot, the AU p-values are defined by pk=1Φ(qk)p_k = 1-\Phi(q_k) for k1k\ge1.

Returns

sbpsi.poly and sbpsi.sing are examples of a sbpsi function; users can develop their own sbpsi functions for better model fitting by preparing sbpsi.foo and sbini.foo

functions for model foo. If check=FALSE, a sbpsi function returns the ψ\psi function value or the extrapolation value. If check=TRUE, a sbpsi function returns NULL when all the elements of beta are included in the their valid intervals. Otherwise, a sbpsi function returns a list with components beta for the parameter value being modified to be on a boundary of the interval and mask, a logical vector indicating which elements are not on the boundary.

sbmodelnames returns a character vector of model names.

Author(s)

Hidetoshi Shimodaira

See Also

sbfit.