get_h_hp | R Documentation |
Generator of h
and hp
(derivative of h
) functions.
get_h_hp(mode, para = NULL, para2 = NULL)
mode |
A string, see details. |
para |
May be optional. A number, the first parameter. Default to |
para2 |
May be optional. A number, the second parameter. If |
The mode
parameter can be chosen from the options listed below along with the corresponding definitions of h
under appropriate choices of para
and para2
parameters. Unless otherwise noted, para
and para2
, must both be strictly positive if provided, and are set to 1 if not provided. Functions h
and hp
should only be applied to non-negative values x
and this is not enforced or checked by the functions.
Internally calls get_h_hp_vector
.
asinh
An asinh function \boldsymbol{h}(\boldsymbol{x})=\mathrm{asinh}(\mathrm{para}\cdot\boldsymbol{x})=\log\left(\mathrm{para}\cdot\boldsymbol{x}+\sqrt{(\mathrm{para}\cdot\boldsymbol{x})^2+1}\right)
. Unbounded and takes one parameter. Equivalent to min_asinh(x, para, Inf)
.
cosh
A shifted cosh function \boldsymbol{h}(\boldsymbol{x})=\cosh(\mathrm{para}\cdot\boldsymbol{x})-1
. Unbounded and takes one parameter. Equivalent to min_cosh(x, para, Inf)
.
exp
A shifted exponential function \boldsymbol{h}(\boldsymbol{x})=\exp(\mathrm{para}\cdot\boldsymbol{x})-1
. Unbounded and takes one parameter. Equivalent to min_exp(x, para, Inf)
.
identity
The identity function \boldsymbol{h}(\boldsymbol{x})=\boldsymbol{x}
. Unbounded and does not take any parameter. Equivalent to pow(x, 1)
or min_pow(x, 1, Inf)
.
log_pow
A power function on a log scale \boldsymbol{h}(\boldsymbol{x})=\log(1+\boldsymbol{x})^{\mathrm{para}}
. Unbounded and takes one parameter. Equivalent to min_log_pow(x, para, Inf)
.
mcp
Treating \lambda
=para, \gamma
=para2, the step-wise MCP function applied element-wise: \lambda x-x^2/(2\gamma)
if x\leq\lambda\gamma
, or \gamma\lambda^2/2
otherwise. Bounded and takes two parameters.
min_asinh
A truncated asinh function applied element-wise: \min(\mathrm{asinh}(\mathrm{para}\cdot\boldsymbol{x}),\mathrm{para}_2)
. Bounded and takes two parameters.
min_asinh_ada
Adaptive version of min_asinh
.
min_cosh
A truncated shifted cosh function applied element-wise: \min(\cosh(\mathrm{para}\cdot\boldsymbol{x})-1,\mathrm{para}_2)
. Bounded and takes two parameters.
min_cosh_ada
Adaptive version of min_cosh
.
min_exp
A truncated shifted exponential function applied element-wise: \boldsymbol{h}(\boldsymbol{x})=\min(\exp(\mathrm{para}\cdot\boldsymbol{x})-1,\mathrm{para}_2)
. Bounded and takes two parameters.
min_exp_ada
Adaptive version of min_exp
.
min_log_pow
A truncated power on a log scale applied element-wise: \boldsymbol{h}(\boldsymbol{x})=\min(\log(1+\boldsymbol{x}),\mathrm{para}_2)^{\mathrm{para}}
. Bounded and takes two parameters.
min_log_pow_ada
Adaptive version of min_log_pow
.
min_pow
A truncated power function applied element-wise: \boldsymbol{h}(\boldsymbol{x})=\min(\boldsymbol{x},\mathrm{para}_2)^{\mathrm{para}}
. Bounded and takes two parameters.
min_pow_ada
Adaptive version of min_pow
.
min_sinh
A truncated sinh function applied element-wise: \min(\sinh(\mathrm{para}\cdot\boldsymbol{x}),\mathrm{para}_2)
. Bounded and takes two parameters.
min_sinh_ada
Adaptive version of min_sinh
.
min_softplus
A truncated shifted softplus function applied element-wise: \min(\log(1+\exp(\mathrm{para}\cdot\boldsymbol{x}))-\log(2),\mathrm{para}_2)
. Bounded and takes two parameters.
min_softplus_ada
Adaptive version of min_softplus
.
pow
A power function \boldsymbol{h}(\boldsymbol{x})=\boldsymbol{x}^{\mathrm{para}}
. Unbounded and takes two parameter. Equivalent to min_pow(x, para, Inf)
.
scad
Treating \lambda
=para, \gamma
=para2, the step-wise SCAD function applied element-wise: \lambda x
if x\leq\lambda
, or (2\gamma\lambda x-x^2-\lambda^2)/(2(\gamma-1))
if \lambda<x<\gamma\lambda
, or \lambda^2(\gamma+1)/2
otherwise. Bounded and takes two parameters, where para2
must be larger than 1, and will be set to 2 by default if not provided.
sinh
A sinh function \boldsymbol{h}(\boldsymbol{x})=\sinh(\mathrm{para}\cdot\boldsymbol{x})
. Unbounded and takes one parameter. Equivalent to min_sinh(x, para, Inf)
.
softplus
A shifted softplus function \boldsymbol{h}(\boldsymbol{x})=\log(1+\exp(\mathrm{para}\cdot\boldsymbol{x}))-\log(2)
. Unbounded and takes one parameter. Equivalent to min_softplus(x, para, Inf)
.
tanh
A tanh function \boldsymbol{h}(\boldsymbol{x})=\tanh(\mathrm{para}\cdot\boldsymbol{x})
. Bounded and takes one parameter.
truncated_sin
A truncated sin function applied element-wise: \sin(\mathrm{para}\cdot x)
if \mathrm{para}\cdot x\leq\pi/2
, or 1 otherwise. Bounded and takes one parameter.
truncated_tan
A truncated tan function applied element-wise: \tan(\mathrm{para}\cdot x)
if \mathrm{para}\cdot x\leq\pi/4
, or 1 otherwise. Bounded and takes one parameter.
For the adaptive modes (names ending with "_ada"
), h
and hp
are first applied to x
without truncation. Then inside each column, values that are larger than the para2
-th quantile will be truncated. The quantile is calculated using finite values only, and if no finite values exist the quantile is set to 1.
For example, if mode == "min_pow_ada"
, para == 2
, para2 == 0.4
, the j
-th column of the returned hx
will be pmin(x[,j]^2, stats::quantile(x[,j]^2, 0.4))
, and the j
-th column of hpx
will be 2*x[,j]*(x[,j] <= stats::quantile(x[,j]^2, 0.4))
.
A function that returns a list containing hx=h(x)
(element-wise) and hpx=hp(x)
(element-wise derivative of h
) when applied to a vector (for mode names not ending with "_ada"
only) or a matrix x
, with both of the results having the same shape as x
.
get_h_hp("mcp", 2, 4)(0:10)
get_h_hp("min_log_pow", 1, log(1+3))(matrix(0:11, nrow=3))
get_h_hp("min_pow", 1.5, 3)(seq(0, 5, by=0.5))
get_h_hp("min_softplus")(matrix(seq(0, 2, by=0.1), nrow=7))
get_h_hp("min_log_pow_ada", 1, 0.4)(matrix(0:49, nrow=10))
get_h_hp("min_pow_ada", 2, 0.3)(matrix(0:49, nrow=10))
get_h_hp("min_softplus_ada", 2, 0.6)(matrix(seq(0, 0.49, by=0.01), nrow=10))
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