add.constraint(tripack)
add.constraint()所属R语言包：tripack
Add a constraint to an triangulaion object
加入一个约束到一个triangulaion的对象。
译者：生物统计家园网 机器人LoveR
描述----------Description----------
This subroutine provides for creation of a constrained Delaunay triangulation which, in some sense, covers an arbitrary connected region R rather than the convex hull of the nodes. This is achieved simply by forcing the presence of certain adjacencies (triangulation arcs) corresponding to constraint curves. The union of triangles coincides with the convex hull of the nodes, but triangles in R can be distinguished from those outside of R. The only modification required to generalize the definition of the Delaunay triangulation is replacement of property 5 (refer to tri.mesh by the following:
这个子程序规定的约束Delaunay三角网的建立，在一定程度上，占地面积任意连接的区域R，而不是凸包的节点。这是通过简单地实现迫使一定的邻接（三角弧）约束曲线对应的存在下。工会的三角形重合的节点的凸包，但在R的三角形可以分为R.以外的唯一需要修改的概括Delaunay三角网的定义是更换物业5（tri.mesh 由下列：
5') If a node is contained in the interior of the circumcircle of a triangle, then every interior point of the triangle is separated from the node by a constraint arc.
5），如果一个节点被包含在一个三角形的外接圆的内部，然后每一个三角形内点的分离从节点通过一个约束电弧。
In order to be explicit, we make the following definitions. A constraint region is the open interior of a simple closed positively oriented polygonal curve defined by an ordered sequence of three or more distinct nodes (constraint nodes) P(1),P(2),...,P(K), such that P(I) is adjacent to P(I+1) for I = 1,...,K with P(K+1) = P(1). Thus, the constraint region is on the left (and may have nonfinite area) as the sequence of constraint nodes is traversed in the specified order. The constraint regions must not contain nodes and must not overlap. The region R is the convex hull of the nodes with constraint regions excluded.
为了是明确的，我们做出如下定义。的约束区域是开放的一个简单的内部的正面面向封闭多边形曲线所定义的有序序列的三个或更多个不同的节点（约束节点）P（1），P（2），...，P（K）中，这样的P（I）是相邻的P（i +1）：I = 1，...，K，其中P（K +1）= P（1）。因此，约束区域是在左边（及可能有非限定的区域）作为约束节点序列中的指定的顺序遍历。约束区域不能包含节点，且不得重叠。区域R的凸包与约束区域的节点排除。
Note that the terms boundary node and boundary arc are reserved for nodes and arcs on the boundary of the convex hull of the nodes.
请注意，术语边界节点和边界圆弧的边界上的凸包的节点的节点和弧的保留。
The algorithm is as follows: given a triangulation which includes one or more sets of constraint nodes, the corresponding adjacencies (constraint arcs) are forced to be present (Fortran subroutine EDGE). Any additional new arcs required are chosen to be locally optimal (satisfy the modified circumcircle property).
该算法如下：给定的三角测量，其中包括一组或多组的约束节点，相应的邻接（约束弧）被迫成为本（Fortran子程序EDGE）。需要任何额外新弧被选择为局部最优（满足的改性的外接圆属性）。
用法----------Usage----------
add.constraint(tri.obj,cstx,csty,reverse=FALSE)
参数----------Arguments----------
参数：tri.obj
object of class "tri"
对象的类"tri"
参数：cstx
vector containing x coordinates of the constraint curve.
矢量包含x坐标的约束曲线。
参数：csty
vector containing y coordinates of the constraint curve.
向量的y坐标的约束曲线。
参数：reverse
if TRUE the orientation of the constraint curve is reversed.
如果TRUE约束曲线的方向是相反的。
值----------Value----------
参考文献----------References----------
R. J. Renka (1996). Algorithm 751: TRIPACK: a constrained two-dimensional Delaunay triangulation package. ACM Transactions on Mathematical Software. 22, 1-8.
参见----------See Also----------
tri, print.tri, plot.tri, summary.tri, triangles, convex.hull.
tri，print.tri，plot.tri，summary.tri，triangles，convex.hull。
实例----------Examples----------
# we will use the simple test data from TRIPACK:[我们将使用简单的测试数据TRIPACK：]
data(tritest)
tritest.tr<-tri.mesh(tritest)
opar<-par(mfrow=c(2,2))
plot(tritest.tr)
# include all points in a big triangle:[包括所有的点在一个大的三角形：]
tritest.tr<-add.constraint(tritest.tr,c(-0.1,2,-0.1),
c(-3,0.5,3),reverse=TRUE)
# insert a small cube:[插入一个小的立方体：]
tritest.tr <- add.constraint(tritest.tr, c(0.4, 0.4,0.6, 0.6),
c(0.6, 0.4,0.4, 0.6),
reverse = FALSE)
par(opar)
转载请注明:出自 生物统计家园网(http://www.biostatistic.net)。
注：
注1：为了方便大家学习，本文档为生物统计家园网机器人LoveR翻译而成，仅供个人R语言学习参考使用，生物统计家园保留版权。
注2：由于是机器人自动翻译，难免有不准确之处，使用时仔细对照中、英文内容进行反复理解，可以帮助R语言的学习。
注3：如遇到不准确之处，请在本贴的后面进行回帖，我们会逐渐进行修订。
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发表于 2012-10-1 12:08:02
