随着Android平台在移动终端的市场占有率越来越高,安卓应用的开发周期越来越短,繁冗且效率底下的Java在新的形势下已渐渐表现出它的疲态,为了解决Android应用开发语言单一的问题,Google发起了SL4A(The Script-ing Layer for Android)项...随着Android平台在移动终端的市场占有率越来越高,安卓应用的开发周期越来越短,繁冗且效率底下的Java在新的形势下已渐渐表现出它的疲态,为了解决Android应用开发语言单一的问题,Google发起了SL4A(The Script-ing Layer for Android)项目。本文简单的介绍了SL4A的工作原理,并以Eclipse和Android SDK为开发工具,在SL4A的支持下使用Python语言实现Android应用GUI的开发。展开更多
By mapping the homogeneous coordinates of two points in space to the Plücker coordinates of the line they determine, any transformation of type SL(4) upon points in space is mapped to a transformation of type SO0...By mapping the homogeneous coordinates of two points in space to the Plücker coordinates of the line they determine, any transformation of type SL(4) upon points in space is mapped to a transformation of type SO0(3, 3), the latter being the connected component containing the identity of the special orthogonal transformation group of the linear space spanned by Plücker coordinates. This is the classical Plücker correspondence, two-to-one and onto. It has important applications in line geometry and projective transformations.While the explicit form of Plücker correspondence is trivial to present, its inverse in explicit form, which is also important in application, is not found in the literature. In this paper, we present a simple and unified formula for the inverse of the Plücker correspondence.展开更多
基金supported by National Natural Science Foundation of China(Grant No.11671388)the CAS Frontier Key Project(Grant No.QYZDJ-SSW-SYS022)
文摘By mapping the homogeneous coordinates of two points in space to the Plücker coordinates of the line they determine, any transformation of type SL(4) upon points in space is mapped to a transformation of type SO0(3, 3), the latter being the connected component containing the identity of the special orthogonal transformation group of the linear space spanned by Plücker coordinates. This is the classical Plücker correspondence, two-to-one and onto. It has important applications in line geometry and projective transformations.While the explicit form of Plücker correspondence is trivial to present, its inverse in explicit form, which is also important in application, is not found in the literature. In this paper, we present a simple and unified formula for the inverse of the Plücker correspondence.
