1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
|
C Output from Public domain Ratfor, version 1.03
subroutine dldins(a,b,slope,rwu,ai,bi,rw,intfnd,bpt,nedge)
implicit double precision(a-h,o-z)
dimension rw(4)
logical intfnd, bpt, rwu
intfnd = .true.
bpt = .true.
xmin = rw(1)
xmax = rw(2)
ymin = rw(3)
ymax = rw(4)
if(xmin.le.a.and.a.le.xmax.and.ymin.le.b.and.b.le.ymax)then
ai = a
bi = b
bpt = .false.
nedge = 0
return
endif
if(.not.rwu)then
if(b .lt. ymin)then
ai = a
bi = ymin
nedge = 1
if(xmin.le.ai.and.ai.le.xmax)then
return
endif
endif
if(b .gt. ymax)then
ai = a
bi = ymax
nedge = 3
if(xmin.le.ai.and.ai.le.xmax)then
return
endif
endif
intfnd = .false.
return
endif
if(a.lt.xmin)then
ai = xmin
bi = b + slope*(ai-a)
nedge = 2
if(ymin.le.bi.and.bi.le.ymax)then
return
endif
endif
if(b.lt.ymin)then
bi = ymin
ai = a + (bi-b)/slope
nedge = 1
if(xmin.le.ai.and.ai.le.xmax)then
return
endif
endif
if(a.gt.xmax)then
ai = xmax
bi = b + slope*(ai-a)
nedge = 4
if(ymin.le.bi.and.bi.le.ymax)then
return
endif
endif
if(b.gt.ymax)then
bi = ymax
ai = a + (bi-b)/slope
nedge = 3
if(xmin.le.ai.and.ai.le.xmax)then
return
endif
endif
intfnd = .false.
return
end
|
