R iGraph graph.bfs and environment -

-

having trouble running breadth-first search algorithm on graph, current concern environment parameter, callback function evaluated.

this callback function

f.in <- function(graph, data, extra) {     time <- get.vertex.attribute(graph, "time", index=data["vid"])     root_time <- get.vertex.attribute(graph, "time", index=extra)     print(ls(environment()))     if (time != 0){           time_difference <- time - root_time          result_list <- c(list(), time_difference)     } }

this context functions called

graphs <- decompose.graph(network_graph, max.comps = na, min.vertices = 0)  lapply(graphs, function(g){     v0 <- which(degree(g, mode="out") == 0)     t0 <- get.vertex.attribute(g, "time", index=v0)     if (t0 != 0) {          bfs_environment <- new.env()          assign("result_list", list(), envir=bfs_environment)          graph.bfs(g, v0, neimode="in", callback=f.in, extra=v0, rho=bfs_environment)     } })

now print of environment shows me following variables "data" "extra" "graph" "root_time" "time"

the question when have passed environment callback function evaluated, why "result_list" not available? there wrong passing environment? btw using r 2.15.3 , igraph 0.7.0

when documentation states:

rho: environment in callback function evaluated

it means passed environment parent of callback environment.

so can retrieve variable using get() , parent.frame() functions, shown in following example:

mycallback <- function(graph, data, extra) {   print(ls(parent.frame()))   print(get('result_list', envir=parent.frame()))   stop('just stop @ first call...') }  # simple tree 3 nodes g <- graph.tree(3, children = 2, mode='out')  bfs_environment <- new.env() assign("result_list", list(a=3), envir=bfs_environment)  graph.bfs(g, 1, callback=mycallback, extra=null, rho=bfs_environment)

output:

[1] "result_list" $a [1] 3

Comments

Post a Comment

Popular posts from this blog

c# - Unity IoC Lifetime per HttpRequest for UserStore -

-
i'm trying clean default implementation of accountcontroller.cs comes out of box in new mvc5/owin security implementation. have modified constructor this: private usermanager<applicationuser> usermanager; public accountcontroller(usermanager<applicationuser> usermanager) { this.usermanager = usermanager; } also, have created lifetime manager unity looks this: public class httpcontextlifetimemanager<t> : lifetimemanager, idisposable { private httpcontextbase _context = null; public httpcontextlifetimemanager() { _context = new httpcontextwrapper(httpcontext.current); } public httpcontextlifetimemanager(httpcontextbase context) { if (context == null) throw new argumentnullexception("context"); _context = context; } public void dispose() { this.removevalue(); } public override object get...
Read more

Change the color of an oval at click in Java AWT -

-
i have draw ovals in java, , @ click change color. beginning tried change color after 20 ms, doesn't work. my code is: public class mycomponentnew extends frame { public graphics2d g2d; public mycomponentnew(string title) { super(title); setsize(400, 550); } @override public void paint(graphics g) { this.g2d = (graphics2d) g; this.g2d.setcolor(color.red); this.g2d.filloval(10, 55, 50, 100); } public void changecolor () { this.g2d.setcolor(color.blue); this.g2d.filloval(10, 55, 50, 100); } } and in class main method have: mycomponentnew m; m = new mycomponentnew("fereastra cu baloane"); m.setvisible(true); m.addwindowlistener(new windowadapter() { @override public void windowclosing(windowevent we) { system.exit(0); } }); try { thread.sleep(20); } catch(interruptedexception e) {} m.changecolor(); the color of oval remains red. ...
Read more

I am trying to solve the error message 'incompatible ranks 0 and 1 in assignment' in a fortran 95 program. -

-
i writing program in fortran find velocity of parachuting person in relation time. keep getting error can't fix. new programming , appreciated. the error is v(i+1)=v(i)+[32-((c*v(i)*v(i))/m)]*(h) 1 error: incompatible ranks 0 , 1 in assignment @ (1) and program is program para integer :: real :: v(11) !velocity real :: q !initial velocity real :: h !time step real :: c !drag coefficient real :: m !mass ! gravity equal 32 ft/s^2 write (*,*)'enter time step' read(*,*)h write(*,*)'enter initial velocity' read(*,*)q write(*,*)'enter drag coefficient' read(*,*)c write(*,*)'enter mass' read(*,*)m i=1,10 ! 1 10, 1 being interval. end v(i+1)=v(i)+[32-((c*v(i)*v(i))/m)]*(h) q=v(1) end program you cannot use [] normal parenthesis in expressions. array constructor, [ items ] means array items elements. end do should after line.
Read more