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include <math.h>
include <math/nlfit.h>
include "../lib/noise.h"
include "../lib/fitpsf.h"
define NPARAMETERS 7
define TOL 0.001
# APSFELGAUSS -- Procedure to fit an elliptical Gaussian function to the
# stellar data.
int procedure apsfelgauss (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 object
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
real gain # the gain parameter
real sigma # constant term to noise
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 elgauss, delgauss
int i, j, npts, fier, imin,imax
pointer sp, x, w, list, zfit, nl, ptr
real sumw, dummy, chisqr, locut, hicut, ptemp
int locpr(), apreject()
real asumr(), apwssqr()
begin
# Initialize.
npts = nx * ny
if (npts < NPARAMETERS)
return (AP_NPSF_TOO_SMALL)
# Allocate working space.
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 up the varaibles array.
ptr = x
do j = 1, ny {
do i = 1, nx {
Memr[ptr] = i
Memr[ptr+1] = j
ptr = ptr + 2
}
}
# Set up 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 fitting parameters.
if (emission == YES)
call ap_wlimr (ctrpix, Memr[w], nx * ny, datamin, datamax,
par[7], par[1], imin, imax)
else
call ap_wlimr (ctrpix, Memr[w], nx * ny, datamin, datamax,
par[7], par[1], imax, imin)
par[1] = par[1] - par[7]
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)
par[5] = (fwhmpsf ** 2 / 4.0)
par[6] = 0.0
# Get the centers and errors.
call nlinitr (nl, locpr (elgauss), locpr (delgauss), 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 (elgauss), locpr (delgauss), par,
perr, NPARAMETERS, Memi[list], NPARAMETERS, TOL, maxiter)
call nlfitr (nl, Memr[x], ctrpix, Memr[w], npts, 2, WTS_USER,
fier)
}
}
# Fetch the parameters.
call nlvectorr (nl, Memr[x], Memr[zfit], npts, 2)
call nlpgetr (nl, par, npar)
par[4] = sqrt (abs(par[4]))
par[5] = sqrt (abs(par[5]))
# Fetch the errors.
call nlerrorsr (nl, ctrpix, Memr[zfit], Memr[w], npts, dummy,
chisqr, perr)
perr[4] = sqrt (perr[4])
perr[5] = sqrt (perr[5])
# Compute the mean errors.
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)
# Transform the parameters.
par[6] = mod (RADTODEG(par[6]), 360.0)
if (par[6] < 0.0)
par[6] = 360.0 + par[6]
if (par[6] > 90.0 && par[6] <= 270.0)
par[6] = par[6] - 180.0
else if (par[6] > 270.0 && par[6] <= 360.0)
par[6] = par[6] - 360.0
if (par[5] > par[4]) {
if (par[6] > 0.0)
par[6] = par[6] - 90.0
else if (par[6] < 0.0)
par[6] = par[6] + 90.0
ptemp = par[4]
par[4] = par[5]
par[5] = ptemp
}
perr[6] = mod (RADTODEG(perr[6]), 360.0)
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
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