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include <math/nlfit.h>
include "../lib/noise.h"
include "../lib/fitpsf.h"
define NPARAMETERS 5
define TOL 0.001
# APSFRADGAUSS -- Fit a radial Gaussian function to the data.
int procedure apsfradgauss (ctrpix, nx, ny, emission, fwhmpsf, datamin,
datamax, noise, gain, sigma, maxiter, k2, nreject, par, perr, npar)
real ctrpix[nx, ny] # object to be centered
int nx, ny # dimensions of subarray
int emission # emission or absorption version
real fwhmpsf # full width half max of the psf
real datamin # minimum good data value
real datamax # maximum good data value
int noise # noise model to be used
real gain # the gain in the data
real sigma # sigma of constant noise term
int maxiter # maximum number of iterations
real k2 # k-sigma rejection criterion
int nreject # maximum number of rejection cycles
real par[ARB] # parameters
real perr[ARB] # errors in parameters
int npar # number of parameters
extern gaussr, dgaussr
int i, j, npts, list, imin, imax, fier
pointer sp, x, w, zfit, nl, ptr
real sumw, dummy, chisqr, locut, hicut
int locpr(), apreject()
real asumr(), apwssqr()
begin
# Initialize.
npts = nx * ny
if (npts < NPARAMETERS)
return (AP_NPSF_TOO_SMALL)
call smark (sp)
call salloc (x, 2 * npts, TY_REAL)
call salloc (w, npts, TY_REAL)
call salloc (zfit, npts, TY_REAL)
call salloc (list, NPARAMETERS, TY_INT)
# Define the active parameters.
do i = 1, NPARAMETERS
Memi[list+i-1] = i
# Set variables array.
ptr = x
do j = 1, ny {
do i = 1, nx {
Memr[ptr] = i
Memr[ptr+1] = j
ptr = ptr + 2
}
}
# Define the weight array.
switch (noise) {
case AP_NCONSTANT:
call amovkr (1.0, Memr[w], npts)
case AP_NPOISSON:
call amaxkr (ctrpix, 0.0, Memr[w], npts)
if (gain > 0.0)
call adivkr (Memr[w], gain, Memr[w], npts)
if (! IS_INDEFR(sigma))
call aaddkr (Memr[w], sigma ** 2, Memr[w], npts)
call apreciprocal (Memr[w], Memr[w], npts, 1.0)
default:
call amovkr (1.0, Memr[w], npts)
}
# Make an initial guess at the parameters.
if (emission == YES)
call ap_wlimr (ctrpix, Memr[w], npts, datamin, datamax,
par[5], par[1], imin, imax)
else
call ap_wlimr (ctrpix, Memr[w], npts, datamin, datamax,
par[1], par[5], imax, imin)
par[1] = par[1] - par[5]
if (mod (imax, nx) == 0)
imin = imax / nx
else
imin = imax / nx + 1
par[3] = imin
imin = imax - (imin - 1) * nx
par[2] = imin
par[4] = (fwhmpsf ** 2 / 4.0)
# Fit the function and the errors.
call nlinitr (nl, locpr (gaussr), locpr (dgaussr), par, perr,
NPARAMETERS, Memi[list], NPARAMETERS, TOL, maxiter)
call nlfitr (nl, Memr[x], ctrpix, Memr[w], npts, 2, WTS_USER, fier)
# Perform the rejection cycle.
if ((nreject > 0) && (k2 > 0.0)) {
do i = 1, nreject {
call nlvectorr (nl, Memr[x], Memr[zfit], npts, 2)
call asubr (ctrpix, Memr[zfit], Memr[zfit], npts)
chisqr = apwssqr (Memr[zfit], Memr[w], npts)
sumw = asumr (Memr[w], npts)
if (sumw <= 0.0)
break
else if (chisqr <= 0.0)
break
else
chisqr = sqrt (chisqr / sumw)
locut = - k2 * chisqr
hicut = k2 * chisqr
if (apreject (Memr[zfit], Memr[w], npts, locut, hicut) == 0)
break
call nlpgetr (nl, par, npar)
call nlfreer (nl)
call nlinitr (nl, locpr (gaussr), locpr (dgaussr), par, perr,
NPARAMETERS, Memi[list], NPARAMETERS, TOL, maxiter)
call nlfitr (nl, Memr[x], ctrpix, Memr[w], npts, 2, WTS_USER,
fier)
}
}
# Get the parameters.
call nlpgetr (nl, par, npar)
par[4] = sqrt (abs(par[4]))
# Get the errors.
call nlvectorr (nl, Memr[x], Memr[zfit], npts, 2)
call nlerrorsr (nl, ctrpix, Memr[zfit], Memr[w], npts, dummy,
chisqr, perr)
perr[4] = sqrt (abs(perr[4]))
# Compute the mean errors in the parameters.
dummy = 0.0
do i = 1, npts {
if (Memr[w+i-1] > 0.0)
dummy = dummy + 1.0
}
dummy = sqrt (dummy)
if (dummy > 0.0)
call adivkr (perr, dummy, perr, npar)
call nlfreer (nl)
call sfree (sp)
# Return the appropriate error code.
if (fier == NO_DEG_FREEDOM) {
return (AP_NPSF_TOO_SMALL)
} else if (fier == SINGULAR) {
return (AP_PSF_SINGULAR)
} else if (fier == NOT_DONE) {
return (AP_PSF_NOCONVERGE)
} else {
return (AP_OK)
}
end
# APREJECT -- Reject points outside of the specified intensity limits by
# setting their weights to zero.
int procedure apreject (pix, w, npts, locut, hicut)
real pix[ARB] # data
real w[ARB] # weights
int npts # number of data points
real locut, hicut # data limits
int i, nreject
begin
nreject = 0
do i = 1, npts {
if ((pix[i] < locut || pix[i] > hicut) && w[i] > 0.0) {
w[i] = 0.0
nreject = nreject + 1
}
}
return (nreject)
end
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