Question

我有一个函数（从MATLAB文档中复制），它在球体内生成随机点。但是，球体内的某些点是不允许的。如何在允许半径为1<r<2的空心球体内生成随机点。换句话说，这些点应该位于1到2的半径上，因此r = [0 1]之间不允许有任何点。

编辑：完全忘记包含该功能

function [x,y,z] = PointsInSphere(r,n)

rvals = 2*rand(n,1)-1;
elevation = asin(rvals);
azimuth = 2*pi*rand(n,1);
radii = r*(rand(n,1).^(1/r));
[x,y,z] = sph2cart(azimuth,elevation,radii);
end

Answer 1

替换

行

2017-04-14 14:39:39,515 ERROR o.a.j.t.g.TestBeanGUI: This should never happen! java.lang.Error: null at org.apache.jmeter.testbeans.gui.TestBeanGUI.<init>(TestBeanGUI.java:159) ~[ApacheJMeter_core.jar:3.2 r1790748] at org.apache.jmeter.gui.GuiPackage.getGuiFromCache(GuiPackage.java:393) ~[ApacheJMeter_core.jar:3.2 r1790748] at org.apache.jmeter.gui.GuiPackage.getGui(GuiPackage.java:245) ~[ApacheJMeter_core.jar:3.2 r1790748] at org.apache.jmeter.gui.GuiPackage.getGui(GuiPackage.java:216) ~[ApacheJMeter_core.jar:3.2 r1790748] at org.apache.jmeter.gui.tree.JMeterTreeModel.addComponent(JMeterTreeModel.java:145) ~[ApacheJMeter_core.jar:3.2 r1790748] at org.apache.jmeter.gui.tree.JMeterTreeModel.addSubTree(JMeterTreeModel.java:121) ~[ApacheJMeter_core.jar:3.2 r1790748] at org.apache.jmeter.gui.tree.JMeterTreeModel.addSubTree(JMeterTreeModel.java:121) ~[ApacheJMeter_core.jar:3.2 r1790748] at org.apache.jmeter.gui.tree.JMeterTreeModel.addSubTree(JMeterTreeModel.java:121) ~[ApacheJMeter_core.jar:3.2 r1790748] at org.apache.jmeter.gui.tree.JMeterTreeModel.addSubTree(JMeterTreeModel.java:113) ~[ApacheJMeter_core.jar:3.2 r1790748] at org.apache.jmeter.gui.GuiPackage.addSubTree(GuiPackage.java:517) ~[ApacheJMeter_core.jar:3.2 r1790748] at org.apache.jmeter.gui.action.Load.insertLoadedTree(Load.java:194) ~[ApacheJMeter_core.jar:3.2 r1790748] at org.apache.jmeter.gui.action.Load.loadProjectFile(Load.java:131) ~[ApacheJMeter_core.jar:3.2 r1790748] at org.apache.jmeter.gui.action.Load.loadProjectFile(Load.java:102) ~[ApacheJMeter_core.jar:3.2 r1790748] at org.apache.jmeter.gui.action.LoadRecentProject.doActionAfterCheck(LoadRecentProject.java:67) ~[ApacheJMeter_core.jar:3.2 r1790748] at org.apache.jmeter.gui.action.AbstractActionWithNoRunningTest.doAction(AbstractActionWithNoRunningTest.java:45) ~[ApacheJMeter_core.jar:3.2 r1790748] at org.apache.jmeter.gui.action.ActionRouter.performAction(ActionRouter.java:74) ~[ApacheJMeter_core.jar:3.2 r1790748] at org.apache.jmeter.gui.action.ActionRouter.lambda$actionPerformed$0(ActionRouter.java:59) ~[ApacheJMeter_core.jar:3.2 r1790748] at java.awt.event.InvocationEvent.dispatch(Unknown Source) [?:1.8.0_111] at java.awt.EventQueue.dispatchEventImpl(Unknown Source) [?:1.8.0_111] at java.awt.EventQueue.access$500(Unknown Source) [?:1.8.0_111] at java.awt.EventQueue$3.run(Unknown Source) [?:1.8.0_111] at java.awt.EventQueue$3.run(Unknown Source) [?:1.8.0_111] at java.security.AccessController.doPrivileged(Native Method) ~[?:1.8.0_111] at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source) [?:1.8.0_111] at java.awt.EventQueue.dispatchEvent(Unknown Source) [?:1.8.0_111] at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source) [?:1.8.0_111] at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source) [?:1.8.0_111] at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source) [?:1.8.0_111] at java.awt.EventDispatchThread.pumpEvents(Unknown Source) [?:1.8.0_111] at java.awt.EventDispatchThread.pumpEvents(Unknown Source) [?:1.8.0_111] at java.awt.EventDispatchThread.run(Unknown Source) [?:1.8.0_111]

通过

radii = r*(rand(n,1).^(1/r));

其中x = (s/r)^r; radii = r*(x+(1-x)*rand(n,1)).^(1/r);是外半径，r是内半径（新函数参数）。

这取代了（s，0） - 统一变量，该变量用于通过（1，x）获得原始函数中的半径 - 统一变量。计算值1，使得获得的半径具有原始分布但截断到区间（x，s）。这可确保在所需区域上生成的3D分布均匀。

Answer 2

您可以轻松生成0到1之间的2个随机数。使用第一个作为半径（加1，使其在[1,2]中）。将第二个随机数乘以2pi。将其从极坐标转换为笛卡尔坐标，你应该完成。

编辑：使用第二个角度移动到3D。

用MATLAB在空心球内生成随机点

2 个答案: