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+# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
+
+include	<mach.h>
+
+# ARAV -- Compute the mean and standard deviation of a sample array by
+# iteratively rejecting points further than KSIG from the mean.  If the
+# value of KSIG is given as 0.0, a cutoff value will be automatically
+# calculated from the standard deviation and number of points in the sample.
+# The number of pixels remaining in the sample upon termination is returned
+# as the function value.
+
+int procedure aravs (a, npix, mean, sigma, ksig)
+
+short	a[ARB]			# input data array
+real	mean, sigma, ksig, deviation, lcut, hcut, lgpx
+int	npix, ngpix, old_ngpix, awvgs()
+
+begin
+	lcut = -MAX_REAL				# no rejection to start
+	hcut =  MAX_REAL
+	ngpix = MAX_INT
+
+	# Iteratively compute mean, sigma and reject outliers until no
+	# more pixels are rejected, or until there are no more pixels.
+
+	repeat {
+	    old_ngpix = ngpix
+	    ngpix = awvgs (a, npix, mean, sigma, lcut, hcut)
+		if (ngpix <= 1 || sigma <= EPSILONR)
+		    break
+
+	    if (ksig == 0.0) {				# Chauvenet's relation
+		lgpx = log10 (real(ngpix))
+		deviation = (lgpx * (-0.1042 * lgpx + 1.1695) + .8895) * sigma
+	    } else
+		deviation = sigma * abs(ksig)
+
+	    lcut = mean - deviation			# compute window
+	    hcut = mean + deviation
+
+	} until (ngpix >= old_ngpix)
+
+	return (ngpix)
+end