R/distance.R

In widals: Weighting by Inverse Distance with Adaptive Least Squares

distance <-
function( locs1, locs2, geodesic=FALSE ) {##### treats 1st column as lat
    #dyn.load("~/Files/Creations/C/distance.so")
    n1 <- nrow(locs1)
    n2 <- nrow(locs2)
    #D.out <- matrix(0, n1, n2)
    d.out <- rep(0, n1 * n2)
    if( geodesic ) {
        D.Mx <- .C("distance_geodesic_AB", as.double(locs1[ ,1]*pi/180), as.double(locs1[ ,2]*pi/180),
        as.double(locs2[ ,1]*pi/180), as.double(locs2[ ,2]*pi/180), as.double(d.out), as.integer(n1), as.integer(n2) )[[5]]
    } else {
        D.Mx <- .C("distance_AB", as.double(locs1[ ,1]), as.double(locs1[ ,2]),
        as.double(locs2[ ,1]), as.double(locs2[ ,2]), as.double(d.out), as.integer(n1), as.integer(n2) )[[5]]
    }
    D.out <- matrix(D.Mx, n1, n2)
    return(D.out)
}