QPmat: Build a projection matrix from a time series of individuals...

In popbio: Construction and Analysis of Matrix Population Models

Build a projection matrix from a time series of individuals (or densities) per stage

Description

Builds one projection matrix from a time series of number (or densities) of individuals per stage (size classes or life stages) using Wood's quadratic programming method. The matrix model also requires a constraint matrix C, vector b, and vector listing nonzero elements of desired projection matrix.

Usage

QPmat(nout, C, b, nonzero)

Arguments

nout	A time series of population vectors
C	constraint matrix
b	b vector
nonzero	indices of the non-zero elements of the transition matrix (counting by column)

Details

converted Matlab code from Example 6.3 in Caswell (2001)

Value

A projection matrix.

Note

This function requires solve.QP in the quadprog package.

Author(s)

Adapted to R by Patrick Nantel

Examples

## Not run: 
## list nonzero elements
nonzero <- c( 1, 2, 5, 6, 7, 9)
## create C matrix
C <- rbind(diag(-1,6), c(1,1,0,0,0,0), c(0,0,1,1,0,0), c(0,0,0,0,0,1))
## calculate b (transpose is not necessary - either way works)
b <- apply(C, 1, max)
QPmat(nematode, C,b,nonzero)

## End(Not run)

popbio documentation built on May 29, 2024, 4:35 a.m.