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$for (sr)
# SIGMA -- Compute sigma line from image lines with rejection.
procedure sigma$t (data, nimages, mean, sigma, npts)
pointer data[nimages] # Data vectors
int nimages # Number of data vectors
$if (datatype == sil)
real mean[npts] # Mean vector
real sigma[npts] # Sigma vector (returned)
$else
PIXEL mean[npts] # Mean vector
PIXEL sigma[npts] # Sigma vector (returned)
$endif
int npts # Number of points in each vector
$if (datatype == sil)
real val, sig, pixval
$else
PIXEL val, sig, pixval
$endif
int i, j, n, n1
begin
n = nimages - 1
do i = 1, npts {
val = mean[i]
sig = 0.
n1 = n
do j = 1, nimages {
pixval = Mem$t[data[j]+i-1]
if (IS_INDEF (pixval))
n1 = n1 - 1
else
sig = sig + (pixval - val) ** 2
}
if (n1 > 0)
sigma[i] = sqrt (sig / n1)
else
sigma[i] = 0.
}
end
# WTSIGMA -- Compute scaled and weighted sigma line from image lines with
# rejection.
procedure wtsigma$t (data, scales, zeros, wts, nimages, mean, sigma, npts)
pointer data[nimages] # Data vectors
real scales[nimages] # Scale factors
real zeros[nimages] # Zero levels
real wts[nimages] # Weights
int nimages # Number of data vectors
$if (datatype == sil)
real mean[npts] # Mean vector
real sigma[npts] # Sigma vector (returned)
real val, sig, pixval
$else
PIXEL mean[npts] # Mean vector
PIXEL sigma[npts] # Sigma vector (returned)
PIXEL val, sig, pixval
$endif
int npts # Number of points in each vector
int i, j, n
real sumwts
begin
do i = 1, npts {
val = mean[i]
n = 0
sig = 0.
sumwts = 0.
do j = 1, nimages {
pixval = Mem$t[data[j]+i-1]
if (!IS_INDEF (pixval)) {
n = n + 1
sig = sig + wts[j]*(pixval/scales[j]-zeros[j]-val) ** 2
sumwts = sumwts + wts[j]
}
}
if (n > 1)
sigma[i] = sqrt (sig / sumwts * n / (n - 1))
else
sigma[i] = 0.
}
end
$endfor
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