dicrf_num {lazy.irt} R Documentation

## Numerical Derivatives of ICRF w.r.t. theta

### Description

Numerical Derivatives of ICRF w.r.t. theta

### Usage

```dicrf_num(param, theta, log = 0, second = 0, eps = 1e-06)
```

### Arguments

 `param` Item Parameter Data Frame `theta` Discrete theta values `log` = 1 to calculate log derivatives. `eps` eps for JacobianMat

### Details

This function uses JacobianMat to calculate the first derivative.

### Value

dICRF length(theta) x sum(ncat) matrix

### Examples

```res1=dicrf_num( paramS1, -1:1 )
res2=dirf( paramS1, -1:1, print=0, plot=0 )\$dICRF
Print(max(abs(res1-res2)))

# second derivative of log P

param=paramS1
param[c(1,4),"p1"]=1

locP=which(param\$type=="P")
locG=which(param\$type=="G")

thmin=-4
thmax=4
npoints=121
theta=seq(thmin,thmax,length=npoints)
pres=fitG2P_ls( param[locP,], plot=1, thmin=thmin, thmax=thmax
, npoints=npoints )
param[locG,]=pres\$paramG
param[locG,"name"]=paste(param\$name[locP],"g", sep="")

log=1
res1=dicrf_num( param, theta, log=log, second=1 )

# all
matplot(theta,res1, type="l", main="2nd deriv. of logP")

# 0-th category: all negative
fromP=get_range(param\$ncat )[,1]
matplot(theta,res1[,fromP], type="l", main="2nd deriv. of logP: 0-th cat")

# all negagive exept for the 1st category of 3PLM
matplot(theta,res1[,-4], type="l"
, main="2nd deriv. of logP: all but 1st of 3PLM")

# 1st category of 3PLM
matplot(theta,res1[,4], type="l", main="2nd deriv. of logP: 1st of 3PLM")

```

[Package lazy.irt version 0.1.3 Index]