clarify run_mod() inputs?

[d-morrison]

niter appears to only get used to define nthin (along with nmc):

serodynamics/R/Run_Mod.R

Lines 92 to 98 in bb40bdc

	# inputs for jags model
	nchains <- nchain # nr of MC chains to run simultaneously
	nadapt <- nadapt # nr of iterations for adaptation
	nburnin <- nburn # nr of iterations to use for burn-in
	nmc <- nmc # nr of samples in posterior chains
	niter <- niter # nr of iterations for posterior sample
	nthin <- round(niter / nmc) # thinning needed to produce nmc from niter

niter is not passed to run.jags() directly:

serodynamics/R/Run_Mod.R

Lines 99 to 114 in bb40bdc

	tomonitor <- c("y0", "y1", "t1", "alpha", "shape")
	jags_post <- runjags::run.jags(
	model = file_mod,
	data = c(longdata, priors),
	inits = initsfunction,
	method = "parallel",
	adapt = nadapt,
	burnin = nburnin,
	thin = nthin,
	sample = nmc,
	n.chains = nchains,
	monitor = tomonitor,
	summarise = FALSE
	)

why not just make nthin an input parameter of run_mod() and remove niter?
I don't understand why run_mod() changes the parametrization from run.jags().