# Phase-independent resetting illustrated with a Fitzhugh-Nagumo-like model
# See P. Smolen and A. Sherman, J. Theor. Biol. (1994) 169:339-348
# Eqs. 4 - 14, Fig. 3

# initial conditions
init v=0.1, j=0.1, s=0.1

# parameters
par vj=0.0, slopej=0.05, vm=0.0
par slopem=0.05, vs=0.0, slopes=0.05
par vjt=0.0, slpjt=0.05, vst=0.0, slpst=0.05
par tjmax=1000.0, tsmax=1000.0
par tjmin=20.0, tsmin=20.0
par gin=1.0, gout=1.0, curbas=0.5
par tstart=5000.0, duration=100.0, amp=-0.5

#odes
v' = -cubic+curin-curout+iapp
j' = (phij-j)/tauj
s' = (phis-s)/taus

# fixed variables
cubic =  (v+1)*v*(v-1)
phij =  1.0/(1.0+exp((v+vj)/slopej))
phim =  1.0/(1.0+exp((vm-v)/slopem))
phis =  1.0/(1.0+exp((vs-v)/slopes))
tauj =  tjmax/(1.0+exp((vjt-v)/slpjt))+tjmin
taus =  tsmax/(1.0+exp((v+vst)/slpst))+tsmin
curin =  gin*phim*j
curout =  gout*s
iapp =  curbas+amp*(heav(t-tstart)-heav(t-tstart-duration))

# auxiliaries for plotting (optional)
aux w =  -gin*phim*j+gout*s
aux iapp =  iapp

@ meth=cvode, total=20000, dt=10, atoler=1.0e-6, toler=1.0e-6
@ ylo=-1.5, yhi=1.5, xlo=0, xhi=20000

done