[statnet_help] error in ergm-term triangle

[霍龙霞]

Hi all,

I use the ergm to model the formation of network. but it is always degeneracy. there are 43 nodes, 492 edeges, 3562 triangles. i use the code as follow:


ergm1<-ergm(net1~edges+triangle,control=control.ergm(seed=2345))



The error message popppes up: 


Model statistics ‘triangle’ are not varying. This may indicate that the observed data occupies an extreme point in the sample space or that the estimation has reached a dead-end configuration.



I also try to use gwesp to solve model degeneracy. the code as follow


ergm1<-ergm(net1~edges+gwesp(0.5, fixed = TRUE),control=control.ergm(seed=2345))


However, it doesn't work, either. And the error as follows: 


Iteration 2 of at most 60:
Error in ergm.MCMLE(init, nw, model, initialfit = (initialfit <- NULL),  :
  Unconstrained MCMC sampling did not mix at all. Optimization cannot continue.
In addition: Warning message:
In ergm_MCMC_sample(s, control, theta = mcmc.init, verbose = max(verbose -  :
  Unable to reach target effective size in iterations alotted.


I want to know is there  any solution to fix this error? 
Thank you very much!



Best,
Longxia Huo
Ph.D. Student
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