// $Id: interpxyz.hoc,v 1.2 2005/09/10 23:02:15 ted Exp $
/* Computes xyz coords of nodes in a model cell
whose topology & geometry are defined by pt3d data.
Expects sections to already exist, and that the xtra mechanism has been inserted
Called in setpointers.hoc
*/
// original data, irregularly spaced
objref xx, yy, zz, length
// interpolated data, spaced at regular intervals
objref xint, yint, zint, range
proc grindaway() { local ii, nn, kk, xr
forall {
if (ismembrane("xtra")) {
// get the data for the section
nn = n3d()
xx = new Vector(nn)
yy = new Vector(nn)
zz = new Vector(nn)
length = new Vector(nn)
for ii = 0,nn1 {
xx.x[ii] = x3d(ii)
yy.x[ii] = y3d(ii)
zz.x[ii] = z3d(ii)
length.x[ii] = arc3d(ii)
}
// to use Vector class's .interpolate()
// must first scale the independent variable
// i.e. normalize length along centroid
length.div(length.x[nn1])
// initialize the destination "independent" vector
range = new Vector(nseg+2)
range.indgen(1/nseg)
range.sub(1/(2*nseg))
range.x[0]=0
range.x[nseg+1]=1
// length contains the normalized distances of the pt3d points
// along the centroid of the section. These are spaced at
// irregular intervals.
// range contains the normalized distances of the nodes along the
// centroid of the section. These are spaced at regular intervals.
// Ready to interpolate.
xint = new Vector(nseg+2)
yint = new Vector(nseg+2)
zint = new Vector(nseg+2)
xint.interpolate(range, length, xx)
yint.interpolate(range, length, yy)
zint.interpolate(range, length, zz)
// for each node, assign the xyz values to x_xtra, y_xtra, z_xtra
// for ii = 0, nseg+1 {
// don't bother computing coords of the 0 and 1 ends
// also avoid writing coords of the 1 end into the last internal node's coords
for ii = 1, nseg {
xr = range.x[ii]
x_xtra(xr) = xint.x[ii]
y_xtra(xr) = yint.x[ii]
z_xtra(xr) = zint.x[ii]
}
}
}
}
