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/* Comparison of implicit and crank-nicholson */
/* showing that C-N can have error oscillations */
/* lambda = sqrt(1e4/4 * diam / (Ra * gl)) microns */
/* tau = 1e-3 * cm / gl msec */
// physical properties of the cell
create a
{access a nseg = 21}
double vt[nseg], vt1[nseg]
// graphical interface appearance
length = 8
objref g
g = new Graph()
g.size(0,length,-.6,1)
proc label() {
g.vfixed(1)
g.label(.315,.01, "x (Lambda)")
g.label(.0,.4, "V")
}
label()
// simulation control
proc init() {
geometry() membrane()
v = 0
v(.5)=1 plotvolt()
}
proc geometry() { local i
L = length
diam = 1
Ra = 1e7/4
}
proc membrane() { local i
insert pas
g_pas = .001
e_pas = 0
}
proc plotvolt() { local x, i
g.beginline()
for (x) {
g.line(x*length, v(x))
}
g.flush()
}
proc run() {
init()
dt = 1
g.color($1)
fadvance() plotvolt() fadvance() plotvolt()
g.flush()
}
// run simulation
{secondorder=0 run(1) secondorder=2 run(2)}
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