QPmat {popbio} | R Documentation |
This function 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.
QPmat(nout, C, b, nonzero)
nout |
A time series of population vectors |
C |
C constraint matrix |
b |
b vector |
nonzero |
indices of the non-zero elements of the transition matrix (counting by column) |
A projection matrix.
This function uses package 'quadprog', which should be installed and loaded on the user's system.
Original Matlab code in Caswell (2001: 148). Adapted to R by Patrick Nantel
converted Matlab code from Example 6.3 in Caswell (2001)
Caswell, H. 2001. Matrix population models. Construction, Analysis and interpretation. 2nd ed. Sinauer, Sunderland, Massachusetts.
data(nematode) ## 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)