SUINTVEL - convert stacking velocity model to interval velocity model

suintvel vs= t0= outpar=/dev/tty

Required parameters:
vs= stacking velocities
t0= normal incidence times

Optional parameters:
outpar=/dev/tty output parameter file in the form:
h=layer thicknesses vector
v=interval velocities vector

Examples:
suintvel vs=5000,5523,6339,7264 t0=.4,.8,1.125,1.425 outpar=intpar

suintvel par=stkpar outpar=intpar

If the file, stkpar, contains:
vs=5000,5523,6339,7264
t0=.4,.8,1.125,1.425
then the two examples are equivalent.

Note: suintvel does not have standard su syntax since it does not
operate on seismic data. Hence stdin and stdout are not used.

Note: may go away in favor of par program, velconv, by Dave


Credits:
CWP: Jack

Technical Reference:
The Common Depth Point Stack
William A. Schneider
Proc. IEEE, v. 72, n. 10, p. 1238-1254
1984

Formulas:
Note: All sums on i are from 1 to k

From Schneider:
Let h[i] be the ith layer thickness measured at the cmp and
v[i] the ith interval velocity.
Set:
t[i] = h[i]/v[i]
Define:
t0by2[k] = 0.5 * t0[k] = Sum h[i]/v[i]
vh[k] = vs[k]*vs[k]*t0by2[k] = Sum v[i]*h[i]
Then:
dt[i] = h[i]/v[i] = t0by2[i] - t0by2[i-1]
dvh[i] = h[i]*v[i] = vh[i] - vh[i-1]
h[i] = sqrt(dvh[i] * dt[i])
v[i] = sqrt(dvh[i] / dt[i])