# inst/ratfor/dppll.r In spatstat: Spatial Point Pattern Analysis, Model-Fitting, Simulation, Tests

```subroutine dppll(x,y,l1,l2,l3,l4,np,nl,eps,mint,rslt,xmin,jmin)
implicit double precision(a-h,o-z)
dimension x(np), y(np), rslt(np,nl), xmin(np), jmin(np)
double precision l1(nl), l2(nl), l3(nl), l4(nl)
one = 1.d0
zero = 0.d0
do j = 1,nl {
dx = l3(j) - l1(j)
dy = l4(j) - l2(j)
alen = sqrt(dx**2 + dy**2)
if(alen .gt. eps) {
co = dx/alen
si = dy/alen
} else {
co = 0.5
si = 0.5
}
do  i = 1, np {
xpx1 = x(i) - l1(j)
ypy1 = y(i) - l2(j)
xpx2 = x(i) - l3(j)
ypy2 = y(i) - l4(j)
d1 = xpx1**2 + ypy1**2
d2 = xpx2**2 + ypy2**2
dd = min(d1,d2)
if(alen .gt. eps) {
xpr = xpx1*co + ypy1*si
if(xpr .lt. zero .or. xpr .gt. alen) {
d3 = -one
}
else {
ypr = - xpx1*si + ypy1*co
d3 = ypr**2
}
}
else {
d3 = -one
}
if(d3 .ge. zero) {
dd = min(dd,d3)
}
sd =sqrt(dd)
rslt(i,j) = sd
if(mint.gt.0) {
if(sd .lt. xmin(i)) {
xmin(i) = sd
if(mint.gt.1) {
jmin(i) = j
}
}
}
}
}
return
end
```

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spatstat documentation built on Aug. 16, 2017, 5:07 p.m.