shape2d {denpro} | R Documentation |

## Returns a 2D volume function or 2D probability content function

### Description

Calculates a 2D volume function or 2D probability content function
from a sequence of shape trees, corresponding to a sequence of level sets of a
multivariate function to be visualized.
A 2D volume function and 2D probability content function
are visualizations of a multivariate density with a 2D function.
One joins a series of radius functions or tail probability functions
to get a 2D visualization.
Radius functions and tail probability functions are 1D functions
which visualize the shape of level sets of a multivariate density.

### Usage

shape2d(shtseq, gnum = 500, type = "radius", type2 = "slice",
gnum2 = 1000, ngrid = 30, norma = FALSE, xmax = 10, modelim = 2,
exmalim = NULL, maxnum = NULL)

### Arguments

`shtseq` |
A list of shape trees, made by function "stseq";
the shape trees in the list correspond to a grid of level sets of the
function to be visualized |

`gnum` |
Number of grid points in the radius function
or in the tail probability function
(used when one transforms a shape tree to a 1D function) |

`type` |
"radius" or "proba"; whether a 2D volume function or 2D
probability content function will be calculated |

`type2` |
"slice" or "boundary"; whether the 1D functions are slices or
level sets of the 2D function. The option "boundary" is not recommended
at the moment |

`gnum2` |
when type2="boundary", then gnum*gnum is the size of the grid
of the 2D function, and "gnum2" is the grid used for transforming
shape trees to 1D functions |

`ngrid` |
positive integer; one prunes the 1D functions to have "ngrid"
level sets |

`norma` |
TRUE if one uses dimension normalization for the volumes;
then volumes are tranformed to (volume/V)pow(1/d), where V is the
volume of the d-dimensional unit ball |

`xmax` |
internal |

`modelim` |
internal |

`exmalim` |
internal |

`maxnum` |
internal |

### Value

A list containing elements x, y, z, whose meaning is the same as in
function "persp".

### Author(s)

Jussi Klemela

### References

Jussi Klemela (2005).
Visualization of the spread of multivariate distributions.

### See Also

`stseq`

,
`plotvolu2d`

### Examples

N<-c(30,30)
lnum<-20
func<-"gumbel"
marginal<-"normal"
g<-2
ver<-3
support<-c(-ver,ver,-ver,ver)
st<-stseq(N,lnum,func=func,marginal=marginal,g=g,support=support)
gnum<-50
ngrid=50
vd<-shape2d(st,gnum=gnum,ngrid=ngrid)
plotvolu2d(vd)
type<-"proba"
vd3<-shape2d(st,gnum=gnum,type=type,ngrid=ngrid,norma=TRUE)
plotvolu2d(vd3)

[Package

*denpro* version 0.9.0

Index]