is `summary` working properly for returning netstats?

[Martina Morris]

This works:

library(tergm) # diss-persist branch
data(samplk)
samplist <- list(samplk1,samplk2,samplk3)
samp.fit <- tergm(
samplist ~
Form(~edges+mutual+cyclicalties+transitiveties) +
Diss(~edges+mutual+cyclicalties+transitiveties),
estimate = "CMLE",
times = c(1:3)
)

So I would have expected this to work, but it doesn't

summary(samplist ~
    Form(~edges+mutual+cyclicalties+transitiveties) +
    Diss(~edges+mutual+cyclicalties+transitiveties),
  estimate = "CMLE",
  times = c(1:3)
	)

Error: A network object on the LHS of the formula or as a basis argument must be given Run `rlang::last_error()` to see where the error occurred.

[Pavel N. Krivitsky]

This is working as intended: summary() has no way of knowing that it's a list of networks.

summary(NetSeries(samplist) ~
    Form(~edges+mutual+cyclicalties+transitiveties) +
    Diss(~edges+mutual+cyclicalties+transitiveties),
  estimate = "CMLE",
  times = c(1:3)
	)

should work fine, though it would probably ignore times.

[Martina Morris]

Thanks. I was hoping to use summary here the same way we do with ergm -- to get the values of the model suff stats. But this makes it clear I don't understand the tergm temporal operator Cross.

The time series of the tergm stats (using tsna):

> tErgmStats(sampdyn, "~edges+mutual+cyclicalties+transitiveties")
Time Series:
Start = 0 
End = 3 
Frequency = 1 
  edges mutual cyclicalties transitiveties
0    55     14           16             18
1    57     15           26             30
2    56     15           33             36
3     0      0            0              0

summary output for the Cross() + Change() model:

> summary(NetSeries(samplist) ~
+     Cross(~edges+mutual+cyclicalties+transitiveties) +
+     Change(~edges+mutual+cyclicalties+transitiveties)
+ 	)
                edges                mutual          cyclicalties 
                  113                    30                    59 
       transitiveties          Change~edges         Change~mutual 
                   66                    75                     7 
  Change~cyclicalties Change~transitiveties 
                   16                    24 

Matches the netstats in the fit object:

> samp.fit2 <- tergm(samplist ~
+     Cross(~edges+mutual+cyclicalties+transitiveties) +
+     Change(~edges+mutual+cyclicalties+transitiveties),
+   estimate = "CMLE",
+   times = c(1:3)
+ 	)
samp.fit2[["nw.stats"]]
                edges                mutual          cyclicalties        transitiveties 
                  113                    30                    59                    66 
         Change~edges         Change~mutual   Change~cyclicalties Change~transitiveties 
                   75                     7                    16                    24

The Cross terms are the sum of the stats for times 2 & 3. I thought they were supposed to be the stats for the first network?

[Pavel N. Krivitsky]

Cross and Change are all functions of network transitions and can only be used on objects that contain the transition information. The others are cross-sectional and can be used on all networks.

[Pavel N. Krivitsky]

I think this is resolved. @martinamorris , if not, please reoopen.