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+# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
+
+include "../icombine.h"
+
+define MINCLIP 3 # Mininum number of images for algorithm
+
+
+# IC_ASIGCLIP -- Reject pixels using sigma clipping about the average
+# The initial average rejects the high and low pixels. A correction for
+# different scalings of the images may be made. Weights are not used.
+
+procedure ic_asigclips (d, m, n, scales, zeros, nimages, npts, average)
+
+pointer d[nimages] # Data pointers
+pointer m[nimages] # Image id pointers
+int n[npts] # Number of good pixels
+real scales[nimages] # Scales
+real zeros[nimages] # Zeros
+int nimages # Number of images
+int npts # Number of output points per line
+real average[npts] # Average
+
+int i, j, k, l, jj, n1, n2, nin, nk, maxkeep
+real d1, low, high, sum, a, s, r, one
+data one /1.0/
+pointer sp, resid, w, wp, dp1, dp2, mp1, mp2
+
+include "../icombine.com"
+
+begin
+ # If there are insufficient pixels go on to the combining
+ if (nkeep < 0)
+ maxkeep = max (0, nimages + nkeep)
+ else
+ maxkeep = min (nimages, nkeep)
+ if (nimages < max (MINCLIP, maxkeep+1) || dflag == D_NONE) {
+ docombine = true
+ return
+ }
+
+ # Flag whether returned average needs to be recomputed.
+ if (dowts || combine != AVERAGE)
+ docombine = true
+ else
+ docombine = false
+
+ # Save the residuals and the sigma scaling corrections if needed.
+ call smark (sp)
+ call salloc (resid, nimages+1, TY_REAL)
+ if (doscale1)
+ call salloc (w, nimages, TY_REAL)
+
+ # Do sigma clipping.
+ nin = n[1]
+ do i = 1, npts {
+ k = i - 1
+ n1 = n[i]
+ if (nkeep < 0)
+ maxkeep = max (0, n1 + nkeep)
+ else
+ maxkeep = min (n1, nkeep)
+
+ # If there are not enough pixels simply compute the average.
+ if (n1 < max (3, maxkeep)) {
+ if (!docombine) {
+ if (n1 == 0)
+ average[i] = blank
+ else {
+ sum = Mems[d[1]+k]
+ do j = 2, n1
+ sum = sum + Mems[d[j]+k]
+ average[i] = sum / n1
+ }
+ }
+ next
+ }
+
+ # Compute average with the high and low rejected.
+ low = Mems[d[1]+k]
+ high = Mems[d[2]+k]
+ if (low > high) {
+ d1 = low
+ low = high
+ high = d1
+ }
+ sum = 0.
+ do j = 3, n1 {
+ d1 = Mems[d[j]+k]
+ if (d1 < low) {
+ sum = sum + low
+ low = d1
+ } else if (d1 > high) {
+ sum = sum + high
+ high = d1
+ } else
+ sum = sum + d1
+ }
+ a = sum / (n1 - 2)
+ sum = sum + low + high
+
+ # Iteratively reject pixels and compute the final average if needed.
+ # Compact the data and keep track of the image IDs if needed.
+
+ repeat {
+ n2 = n1
+ if (doscale1) {
+ # Compute sigma corrected for scaling.
+ s = 0.
+ wp = w - 1
+ do j = 1, n1 {
+ dp1 = d[j] + k
+ mp1 = m[j] + k
+ wp = wp + 1
+
+ d1 = Mems[dp1]
+ l = Memi[mp1]
+ r = sqrt (max (one, (a + zeros[l]) / scales[l]))
+ s = s + ((d1 - a) / r) ** 2
+ Memr[wp] = r
+ }
+ s = sqrt (s / (n1 - 1))
+
+ # Reject pixels. Save the residuals and data values.
+ wp = w - 1
+ if (s > 0.) {
+ for (j=1; j<=n1; j=j+1) {
+ dp1 = d[j] + k
+ mp1 = m[j] + k
+ wp = wp + 1
+
+ d1 = Mems[dp1]
+ r = (d1 - a) / (s * Memr[wp])
+ if (r < -lsigma || r > hsigma) {
+ Memr[resid+n1] = abs (r)
+ if (j < n1) {
+ dp2 = d[n1] + k
+ Mems[dp1] = Mems[dp2]
+ Mems[dp2] = d1
+ Memr[wp] = Memr[w+n1-1]
+ mp2 = m[n1] + k
+ l = Memi[mp1]
+ Memi[mp1] = Memi[mp2]
+ Memi[mp2] = l
+ j = j - 1
+ }
+ sum = sum - d1
+ n1 = n1 - 1
+ }
+ }
+ }
+ } else {
+ # Compute the sigma without scale correction.
+ s = 0.
+ do j = 1, n1
+ s = s + (Mems[d[j]+k] - a) ** 2
+ s = sqrt (s / (n1 - 1))
+
+ # Reject pixels. Save the residuals and data values.
+ if (s > 0.) {
+ for (j=1; j<=n1; j=j+1) {
+ dp1 = d[j] + k
+ d1 = Mems[dp1]
+ r = (d1 - a) / s
+ if (r < -lsigma || r > hsigma) {
+ Memr[resid+n1] = abs (r)
+ if (j < n1) {
+ dp2 = d[n1] + k
+ Mems[dp1] = Mems[dp2]
+ Mems[dp2] = d1
+ if (keepids) {
+ mp1 = m[j] + k
+ mp2 = m[n1] + k
+ l = Memi[mp1]
+ Memi[mp1] = Memi[mp2]
+ Memi[mp2] = l
+ }
+ j = j - 1
+ }
+ sum = sum - d1
+ n1 = n1 - 1
+ }
+ }
+ }
+ }
+
+ # Recompute the average.
+ if (n1 > 1)
+ a = sum / n1
+ } until (n1 == n2 || n1 <= max (2, maxkeep))
+
+ # If too many pixels are rejected add some back.
+ # All pixels with equal residuals are added back.
+ if (n1 < maxkeep) {
+ nk = maxkeep
+ if (doscale1) {
+ for (j=n1+1; j<=nk; j=j+1) {
+ dp1 = d[j] + k
+ mp1 = m[j] + k
+ r = Memr[resid+j]
+ jj = 0
+ do l = j+1, n2 {
+ s = Memr[resid+l]
+ if (s < r + TOL) {
+ if (s > r - TOL)
+ jj = jj + 1
+ else {
+ jj = 0
+ Memr[resid+l] = r
+ r = s
+ dp2 = d[l] + k
+ d1 = Mems[dp1]
+ Mems[dp1] = Mems[dp2]
+ Mems[dp2] = d1
+ mp2 = m[l] + k
+ s = Memi[mp1]
+ Memi[mp1] = Memi[mp2]
+ Memi[mp2] = s
+ }
+ }
+ }
+ sum = sum + Mems[dp1]
+ n1 = n1 + 1
+ nk = max (nk, j+jj)
+ }
+ } else {
+ for (j=n1+1; j<=nk; j=j+1) {
+ dp1 = d[j] + k
+ r = Memr[resid+j]
+ jj = 0
+ do l = j+1, n2 {
+ s = Memr[resid+l]
+ if (s < r + TOL) {
+ if (s > r - TOL)
+ jj = jj + 1
+ else {
+ jj = 0
+ Memr[resid+l] = r
+ r = s
+ dp2 = d[l] + k
+ d1 = Mems[dp1]
+ Mems[dp1] = Mems[dp2]
+ Mems[dp2] = d1
+ if (keepids) {
+ mp1 = m[j] + k
+ mp2 = m[l] + k
+ s = Memi[mp1]
+ Memi[mp1] = Memi[mp2]
+ Memi[mp2] = s
+ }
+ }
+ }
+ }
+ sum = sum + Mems[dp1]
+ n1 = n1 + 1
+ nk = max (nk, j+jj)
+ }
+ }
+
+ # Recompute the average.
+ if (n1 > 1)
+ a = sum / n1
+ }
+
+ # Save the average if needed.
+ n[i] = n1
+ if (!docombine) {
+ if (n1 > 0)
+ average[i] = a
+ else
+ average[i] = blank
+ }
+ }
+
+ # Check if the data flag has to be reset for rejected pixels
+ if (dflag == D_ALL) {
+ do i = 1, npts {
+ if (n[i] != nin) {
+ dflag = D_MIX
+ break
+ }
+ }
+ }
+
+ call sfree (sp)
+end
+
+
+# IC_MSIGCLIP -- Reject pixels using sigma clipping about the median
+
+procedure ic_msigclips (d, m, n, scales, zeros, nimages, npts, median)
+
+pointer d[nimages] # Data pointers
+pointer m[nimages] # Image id pointers
+int n[npts] # Number of good pixels
+real scales[nimages] # Scales
+real zeros[nimages] # Zeros
+int nimages # Number of images
+int npts # Number of output points per line
+real median[npts] # Median
+
+int i, j, k, l, id, n1, n2, n3, nl, nh, nin, maxkeep
+real r, s
+pointer sp, resid, w, mp1, mp2
+real med, one
+data one /1.0/
+
+include "../icombine.com"
+
+begin
+ # If there are insufficient pixels go on to the combining
+ if (nkeep < 0)
+ maxkeep = max (0, nimages + nkeep)
+ else
+ maxkeep = min (nimages, nkeep)
+ if (nimages < max (MINCLIP, maxkeep+1) || dflag == D_NONE) {
+ docombine = true
+ return
+ }
+
+ # Save the residuals and sigma scaling corrections if needed.
+ call smark (sp)
+ call salloc (resid, nimages+1, TY_REAL)
+ if (doscale1)
+ call salloc (w, nimages, TY_REAL)
+
+ # Compute median and sigma and iteratively clip.
+ nin = n[1]
+ do i = 1, npts {
+ k = i - 1
+ n1 = n[i]
+ if (nkeep < 0)
+ maxkeep = max (0, n1 + nkeep)
+ else
+ maxkeep = min (n1, nkeep)
+ nl = 1
+ nh = n1
+
+ repeat {
+ n2 = n1
+ n3 = nl + n1 / 2
+
+ if (n1 == 0)
+ med = blank
+ else if (mod (n1, 2) == 0)
+ med = (Mems[d[n3-1]+k] + Mems[d[n3]+k]) / 2.
+ else
+ med = Mems[d[n3]+k]
+
+ if (n1 >= max (MINCLIP, maxkeep+1)) {
+ if (doscale1) {
+ # Compute the sigma with scaling correction.
+ s = 0.
+ do j = nl, nh {
+ l = Memi[m[j]+k]
+ r = sqrt (max (one, (med + zeros[l]) / scales[l]))
+ s = s + ((Mems[d[j]+k] - med) / r) ** 2
+ Memr[w+j-1] = r
+ }
+ s = sqrt (s / (n1 - 1))
+
+ # Reject pixels and save the residuals.
+ if (s > 0.) {
+ for (; nl <= n2; nl = nl + 1) {
+ r = (med - Mems[d[nl]+k]) / (s * Memr[w+nl-1])
+ if (r <= lsigma)
+ break
+ Memr[resid+nl] = r
+ n1 = n1 - 1
+ }
+ for (; nh >= nl; nh = nh - 1) {
+ r = (Mems[d[nh]+k] - med) / (s * Memr[w+nh-1])
+ if (r <= hsigma)
+ break
+ Memr[resid+nh] = r
+ n1 = n1 - 1
+ }
+ }
+ } else {
+ # Compute the sigma without scaling correction.
+ s = 0.
+ do j = nl, nh
+ s = s + (Mems[d[j]+k] - med) ** 2
+ s = sqrt (s / (n1 - 1))
+
+ # Reject pixels and save the residuals.
+ if (s > 0.) {
+ for (; nl <= n2; nl = nl + 1) {
+ r = (med - Mems[d[nl]+k]) / s
+ if (r <= lsigma)
+ break
+ Memr[resid+nl] = r
+ n1 = n1 - 1
+ }
+ for (; nh >= nl; nh = nh - 1) {
+ r = (Mems[d[nh]+k] - med) / s
+ if (r <= hsigma)
+ break
+ Memr[resid+nh] = r
+ n1 = n1 - 1
+ }
+ }
+ }
+ }
+ } until (n1 == n2 || n1 < max (MINCLIP, maxkeep+1))
+
+ # If too many pixels are rejected add some back.
+ # All pixels with equal residuals are added back.
+ while (n1 < maxkeep) {
+ if (nl == 1)
+ nh = nh + 1
+ else if (nh == n[i])
+ nl = nl - 1
+ else {
+ r = Memr[resid+nl-1]
+ s = Memr[resid+nh+1]
+ if (r < s) {
+ nl = nl - 1
+ r = r + TOL
+ if (s <= r)
+ nh = nh + 1
+ if (nl > 1) {
+ if (Memr[resid+nl-1] <= r)
+ nl = nl - 1
+ }
+ } else {
+ nh = nh + 1
+ s = s + TOL
+ if (r <= s)
+ nl = nl - 1
+ if (nh < n2) {
+ if (Memr[resid+nh+1] <= s)
+ nh = nh + 1
+ }
+ }
+ }
+ n1 = nh - nl + 1
+ }
+
+ # Only set median and reorder if needed
+ n[i] = n1
+ if (n1 > 0 && nl > 1 && (combine != MEDIAN || grow >= 1.)) {
+ j = max (nl, n1 + 1)
+ if (keepids) {
+ do l = 1, min (n1, nl-1) {
+ Mems[d[l]+k] = Mems[d[j]+k]
+ if (grow >= 1.) {
+ mp1 = m[l] + k
+ mp2 = m[j] + k
+ id = Memi[mp1]
+ Memi[mp1] = Memi[mp2]
+ Memi[mp2] = id
+ } else
+ Memi[m[l]+k] = Memi[m[j]+k]
+ j = j + 1
+ }
+ } else {
+ do l = 1, min (n1, nl - 1) {
+ Mems[d[l]+k] = Mems[d[j]+k]
+ j = j + 1
+ }
+ }
+ }
+
+ if (combine == MEDIAN)
+ median[i] = med
+ }
+
+ # Check if data flag needs to be reset for rejected pixels
+ if (dflag == D_ALL) {
+ do i = 1, npts {
+ if (n[i] != nin) {
+ dflag = D_MIX
+ break
+ }
+ }
+ }
+
+ # Flag that the median has been computed.
+ if (combine == MEDIAN)
+ docombine = false
+ else
+ docombine = true
+
+ call sfree (sp)
+end
+
+# IC_ASIGCLIP -- Reject pixels using sigma clipping about the average
+# The initial average rejects the high and low pixels. A correction for
+# different scalings of the images may be made. Weights are not used.
+
+procedure ic_asigclipi (d, m, n, scales, zeros, nimages, npts, average)
+
+pointer d[nimages] # Data pointers
+pointer m[nimages] # Image id pointers
+int n[npts] # Number of good pixels
+real scales[nimages] # Scales
+real zeros[nimages] # Zeros
+int nimages # Number of images
+int npts # Number of output points per line
+real average[npts] # Average
+
+int i, j, k, l, jj, n1, n2, nin, nk, maxkeep
+real d1, low, high, sum, a, s, r, one
+data one /1.0/
+pointer sp, resid, w, wp, dp1, dp2, mp1, mp2
+
+include "../icombine.com"
+
+begin
+ # If there are insufficient pixels go on to the combining
+ if (nkeep < 0)
+ maxkeep = max (0, nimages + nkeep)
+ else
+ maxkeep = min (nimages, nkeep)
+ if (nimages < max (MINCLIP, maxkeep+1) || dflag == D_NONE) {
+ docombine = true
+ return
+ }
+
+ # Flag whether returned average needs to be recomputed.
+ if (dowts || combine != AVERAGE)
+ docombine = true
+ else
+ docombine = false
+
+ # Save the residuals and the sigma scaling corrections if needed.
+ call smark (sp)
+ call salloc (resid, nimages+1, TY_REAL)
+ if (doscale1)
+ call salloc (w, nimages, TY_REAL)
+
+ # Do sigma clipping.
+ nin = n[1]
+ do i = 1, npts {
+ k = i - 1
+ n1 = n[i]
+ if (nkeep < 0)
+ maxkeep = max (0, n1 + nkeep)
+ else
+ maxkeep = min (n1, nkeep)
+
+ # If there are not enough pixels simply compute the average.
+ if (n1 < max (3, maxkeep)) {
+ if (!docombine) {
+ if (n1 == 0)
+ average[i] = blank
+ else {
+ sum = Memi[d[1]+k]
+ do j = 2, n1
+ sum = sum + Memi[d[j]+k]
+ average[i] = sum / n1
+ }
+ }
+ next
+ }
+
+ # Compute average with the high and low rejected.
+ low = Memi[d[1]+k]
+ high = Memi[d[2]+k]
+ if (low > high) {
+ d1 = low
+ low = high
+ high = d1
+ }
+ sum = 0.
+ do j = 3, n1 {
+ d1 = Memi[d[j]+k]
+ if (d1 < low) {
+ sum = sum + low
+ low = d1
+ } else if (d1 > high) {
+ sum = sum + high
+ high = d1
+ } else
+ sum = sum + d1
+ }
+ a = sum / (n1 - 2)
+ sum = sum + low + high
+
+ # Iteratively reject pixels and compute the final average if needed.
+ # Compact the data and keep track of the image IDs if needed.
+
+ repeat {
+ n2 = n1
+ if (doscale1) {
+ # Compute sigma corrected for scaling.
+ s = 0.
+ wp = w - 1
+ do j = 1, n1 {
+ dp1 = d[j] + k
+ mp1 = m[j] + k
+ wp = wp + 1
+
+ d1 = Memi[dp1]
+ l = Memi[mp1]
+ r = sqrt (max (one, (a + zeros[l]) / scales[l]))
+ s = s + ((d1 - a) / r) ** 2
+ Memr[wp] = r
+ }
+ s = sqrt (s / (n1 - 1))
+
+ # Reject pixels. Save the residuals and data values.
+ wp = w - 1
+ if (s > 0.) {
+ for (j=1; j<=n1; j=j+1) {
+ dp1 = d[j] + k
+ mp1 = m[j] + k
+ wp = wp + 1
+
+ d1 = Memi[dp1]
+ r = (d1 - a) / (s * Memr[wp])
+ if (r < -lsigma || r > hsigma) {
+ Memr[resid+n1] = abs (r)
+ if (j < n1) {
+ dp2 = d[n1] + k
+ Memi[dp1] = Memi[dp2]
+ Memi[dp2] = d1
+ Memr[wp] = Memr[w+n1-1]
+ mp2 = m[n1] + k
+ l = Memi[mp1]
+ Memi[mp1] = Memi[mp2]
+ Memi[mp2] = l
+ j = j - 1
+ }
+ sum = sum - d1
+ n1 = n1 - 1
+ }
+ }
+ }
+ } else {
+ # Compute the sigma without scale correction.
+ s = 0.
+ do j = 1, n1
+ s = s + (Memi[d[j]+k] - a) ** 2
+ s = sqrt (s / (n1 - 1))
+
+ # Reject pixels. Save the residuals and data values.
+ if (s > 0.) {
+ for (j=1; j<=n1; j=j+1) {
+ dp1 = d[j] + k
+ d1 = Memi[dp1]
+ r = (d1 - a) / s
+ if (r < -lsigma || r > hsigma) {
+ Memr[resid+n1] = abs (r)
+ if (j < n1) {
+ dp2 = d[n1] + k
+ Memi[dp1] = Memi[dp2]
+ Memi[dp2] = d1
+ if (keepids) {
+ mp1 = m[j] + k
+ mp2 = m[n1] + k
+ l = Memi[mp1]
+ Memi[mp1] = Memi[mp2]
+ Memi[mp2] = l
+ }
+ j = j - 1
+ }
+ sum = sum - d1
+ n1 = n1 - 1
+ }
+ }
+ }
+ }
+
+ # Recompute the average.
+ if (n1 > 1)
+ a = sum / n1
+ } until (n1 == n2 || n1 <= max (2, maxkeep))
+
+ # If too many pixels are rejected add some back.
+ # All pixels with equal residuals are added back.
+ if (n1 < maxkeep) {
+ nk = maxkeep
+ if (doscale1) {
+ for (j=n1+1; j<=nk; j=j+1) {
+ dp1 = d[j] + k
+ mp1 = m[j] + k
+ r = Memr[resid+j]
+ jj = 0
+ do l = j+1, n2 {
+ s = Memr[resid+l]
+ if (s < r + TOL) {
+ if (s > r - TOL)
+ jj = jj + 1
+ else {
+ jj = 0
+ Memr[resid+l] = r
+ r = s
+ dp2 = d[l] + k
+ d1 = Memi[dp1]
+ Memi[dp1] = Memi[dp2]
+ Memi[dp2] = d1
+ mp2 = m[l] + k
+ s = Memi[mp1]
+ Memi[mp1] = Memi[mp2]
+ Memi[mp2] = s
+ }
+ }
+ }
+ sum = sum + Memi[dp1]
+ n1 = n1 + 1
+ nk = max (nk, j+jj)
+ }
+ } else {
+ for (j=n1+1; j<=nk; j=j+1) {
+ dp1 = d[j] + k
+ r = Memr[resid+j]
+ jj = 0
+ do l = j+1, n2 {
+ s = Memr[resid+l]
+ if (s < r + TOL) {
+ if (s > r - TOL)
+ jj = jj + 1
+ else {
+ jj = 0
+ Memr[resid+l] = r
+ r = s
+ dp2 = d[l] + k
+ d1 = Memi[dp1]
+ Memi[dp1] = Memi[dp2]
+ Memi[dp2] = d1
+ if (keepids) {
+ mp1 = m[j] + k
+ mp2 = m[l] + k
+ s = Memi[mp1]
+ Memi[mp1] = Memi[mp2]
+ Memi[mp2] = s
+ }
+ }
+ }
+ }
+ sum = sum + Memi[dp1]
+ n1 = n1 + 1
+ nk = max (nk, j+jj)
+ }
+ }
+
+ # Recompute the average.
+ if (n1 > 1)
+ a = sum / n1
+ }
+
+ # Save the average if needed.
+ n[i] = n1
+ if (!docombine) {
+ if (n1 > 0)
+ average[i] = a
+ else
+ average[i] = blank
+ }
+ }
+
+ # Check if the data flag has to be reset for rejected pixels
+ if (dflag == D_ALL) {
+ do i = 1, npts {
+ if (n[i] != nin) {
+ dflag = D_MIX
+ break
+ }
+ }
+ }
+
+ call sfree (sp)
+end
+
+
+# IC_MSIGCLIP -- Reject pixels using sigma clipping about the median
+
+procedure ic_msigclipi (d, m, n, scales, zeros, nimages, npts, median)
+
+pointer d[nimages] # Data pointers
+pointer m[nimages] # Image id pointers
+int n[npts] # Number of good pixels
+real scales[nimages] # Scales
+real zeros[nimages] # Zeros
+int nimages # Number of images
+int npts # Number of output points per line
+real median[npts] # Median
+
+int i, j, k, l, id, n1, n2, n3, nl, nh, nin, maxkeep
+real r, s
+pointer sp, resid, w, mp1, mp2
+real med, one
+data one /1.0/
+
+include "../icombine.com"
+
+begin
+ # If there are insufficient pixels go on to the combining
+ if (nkeep < 0)
+ maxkeep = max (0, nimages + nkeep)
+ else
+ maxkeep = min (nimages, nkeep)
+ if (nimages < max (MINCLIP, maxkeep+1) || dflag == D_NONE) {
+ docombine = true
+ return
+ }
+
+ # Save the residuals and sigma scaling corrections if needed.
+ call smark (sp)
+ call salloc (resid, nimages+1, TY_REAL)
+ if (doscale1)
+ call salloc (w, nimages, TY_REAL)
+
+ # Compute median and sigma and iteratively clip.
+ nin = n[1]
+ do i = 1, npts {
+ k = i - 1
+ n1 = n[i]
+ if (nkeep < 0)
+ maxkeep = max (0, n1 + nkeep)
+ else
+ maxkeep = min (n1, nkeep)
+ nl = 1
+ nh = n1
+
+ repeat {
+ n2 = n1
+ n3 = nl + n1 / 2
+
+ if (n1 == 0)
+ med = blank
+ else if (mod (n1, 2) == 0)
+ med = (Memi[d[n3-1]+k] + Memi[d[n3]+k]) / 2.
+ else
+ med = Memi[d[n3]+k]
+
+ if (n1 >= max (MINCLIP, maxkeep+1)) {
+ if (doscale1) {
+ # Compute the sigma with scaling correction.
+ s = 0.
+ do j = nl, nh {
+ l = Memi[m[j]+k]
+ r = sqrt (max (one, (med + zeros[l]) / scales[l]))
+ s = s + ((Memi[d[j]+k] - med) / r) ** 2
+ Memr[w+j-1] = r
+ }
+ s = sqrt (s / (n1 - 1))
+
+ # Reject pixels and save the residuals.
+ if (s > 0.) {
+ for (; nl <= n2; nl = nl + 1) {
+ r = (med - Memi[d[nl]+k]) / (s * Memr[w+nl-1])
+ if (r <= lsigma)
+ break
+ Memr[resid+nl] = r
+ n1 = n1 - 1
+ }
+ for (; nh >= nl; nh = nh - 1) {
+ r = (Memi[d[nh]+k] - med) / (s * Memr[w+nh-1])
+ if (r <= hsigma)
+ break
+ Memr[resid+nh] = r
+ n1 = n1 - 1
+ }
+ }
+ } else {
+ # Compute the sigma without scaling correction.
+ s = 0.
+ do j = nl, nh
+ s = s + (Memi[d[j]+k] - med) ** 2
+ s = sqrt (s / (n1 - 1))
+
+ # Reject pixels and save the residuals.
+ if (s > 0.) {
+ for (; nl <= n2; nl = nl + 1) {
+ r = (med - Memi[d[nl]+k]) / s
+ if (r <= lsigma)
+ break
+ Memr[resid+nl] = r
+ n1 = n1 - 1
+ }
+ for (; nh >= nl; nh = nh - 1) {
+ r = (Memi[d[nh]+k] - med) / s
+ if (r <= hsigma)
+ break
+ Memr[resid+nh] = r
+ n1 = n1 - 1
+ }
+ }
+ }
+ }
+ } until (n1 == n2 || n1 < max (MINCLIP, maxkeep+1))
+
+ # If too many pixels are rejected add some back.
+ # All pixels with equal residuals are added back.
+ while (n1 < maxkeep) {
+ if (nl == 1)
+ nh = nh + 1
+ else if (nh == n[i])
+ nl = nl - 1
+ else {
+ r = Memr[resid+nl-1]
+ s = Memr[resid+nh+1]
+ if (r < s) {
+ nl = nl - 1
+ r = r + TOL
+ if (s <= r)
+ nh = nh + 1
+ if (nl > 1) {
+ if (Memr[resid+nl-1] <= r)
+ nl = nl - 1
+ }
+ } else {
+ nh = nh + 1
+ s = s + TOL
+ if (r <= s)
+ nl = nl - 1
+ if (nh < n2) {
+ if (Memr[resid+nh+1] <= s)
+ nh = nh + 1
+ }
+ }
+ }
+ n1 = nh - nl + 1
+ }
+
+ # Only set median and reorder if needed
+ n[i] = n1
+ if (n1 > 0 && nl > 1 && (combine != MEDIAN || grow >= 1.)) {
+ j = max (nl, n1 + 1)
+ if (keepids) {
+ do l = 1, min (n1, nl-1) {
+ Memi[d[l]+k] = Memi[d[j]+k]
+ if (grow >= 1.) {
+ mp1 = m[l] + k
+ mp2 = m[j] + k
+ id = Memi[mp1]
+ Memi[mp1] = Memi[mp2]
+ Memi[mp2] = id
+ } else
+ Memi[m[l]+k] = Memi[m[j]+k]
+ j = j + 1
+ }
+ } else {
+ do l = 1, min (n1, nl - 1) {
+ Memi[d[l]+k] = Memi[d[j]+k]
+ j = j + 1
+ }
+ }
+ }
+
+ if (combine == MEDIAN)
+ median[i] = med
+ }
+
+ # Check if data flag needs to be reset for rejected pixels
+ if (dflag == D_ALL) {
+ do i = 1, npts {
+ if (n[i] != nin) {
+ dflag = D_MIX
+ break
+ }
+ }
+ }
+
+ # Flag that the median has been computed.
+ if (combine == MEDIAN)
+ docombine = false
+ else
+ docombine = true
+
+ call sfree (sp)
+end
+
+# IC_ASIGCLIP -- Reject pixels using sigma clipping about the average
+# The initial average rejects the high and low pixels. A correction for
+# different scalings of the images may be made. Weights are not used.
+
+procedure ic_asigclipr (d, m, n, scales, zeros, nimages, npts, average)
+
+pointer d[nimages] # Data pointers
+pointer m[nimages] # Image id pointers
+int n[npts] # Number of good pixels
+real scales[nimages] # Scales
+real zeros[nimages] # Zeros
+int nimages # Number of images
+int npts # Number of output points per line
+real average[npts] # Average
+
+int i, j, k, l, jj, n1, n2, nin, nk, maxkeep
+real d1, low, high, sum, a, s, r, one
+data one /1.0/
+pointer sp, resid, w, wp, dp1, dp2, mp1, mp2
+
+include "../icombine.com"
+
+begin
+ # If there are insufficient pixels go on to the combining
+ if (nkeep < 0)
+ maxkeep = max (0, nimages + nkeep)
+ else
+ maxkeep = min (nimages, nkeep)
+ if (nimages < max (MINCLIP, maxkeep+1) || dflag == D_NONE) {
+ docombine = true
+ return
+ }
+
+ # Flag whether returned average needs to be recomputed.
+ if (dowts || combine != AVERAGE)
+ docombine = true
+ else
+ docombine = false
+
+ # Save the residuals and the sigma scaling corrections if needed.
+ call smark (sp)
+ call salloc (resid, nimages+1, TY_REAL)
+ if (doscale1)
+ call salloc (w, nimages, TY_REAL)
+
+ # Do sigma clipping.
+ nin = n[1]
+ do i = 1, npts {
+ k = i - 1
+ n1 = n[i]
+ if (nkeep < 0)
+ maxkeep = max (0, n1 + nkeep)
+ else
+ maxkeep = min (n1, nkeep)
+
+ # If there are not enough pixels simply compute the average.
+ if (n1 < max (3, maxkeep)) {
+ if (!docombine) {
+ if (n1 == 0)
+ average[i] = blank
+ else {
+ sum = Memr[d[1]+k]
+ do j = 2, n1
+ sum = sum + Memr[d[j]+k]
+ average[i] = sum / n1
+ }
+ }
+ next
+ }
+
+ # Compute average with the high and low rejected.
+ low = Memr[d[1]+k]
+ high = Memr[d[2]+k]
+ if (low > high) {
+ d1 = low
+ low = high
+ high = d1
+ }
+ sum = 0.
+ do j = 3, n1 {
+ d1 = Memr[d[j]+k]
+ if (d1 < low) {
+ sum = sum + low
+ low = d1
+ } else if (d1 > high) {
+ sum = sum + high
+ high = d1
+ } else
+ sum = sum + d1
+ }
+ a = sum / (n1 - 2)
+ sum = sum + low + high
+
+ # Iteratively reject pixels and compute the final average if needed.
+ # Compact the data and keep track of the image IDs if needed.
+
+ repeat {
+ n2 = n1
+ if (doscale1) {
+ # Compute sigma corrected for scaling.
+ s = 0.
+ wp = w - 1
+ do j = 1, n1 {
+ dp1 = d[j] + k
+ mp1 = m[j] + k
+ wp = wp + 1
+
+ d1 = Memr[dp1]
+ l = Memi[mp1]
+ r = sqrt (max (one, (a + zeros[l]) / scales[l]))
+ s = s + ((d1 - a) / r) ** 2
+ Memr[wp] = r
+ }
+ s = sqrt (s / (n1 - 1))
+
+ # Reject pixels. Save the residuals and data values.
+ wp = w - 1
+ if (s > 0.) {
+ for (j=1; j<=n1; j=j+1) {
+ dp1 = d[j] + k
+ mp1 = m[j] + k
+ wp = wp + 1
+
+ d1 = Memr[dp1]
+ r = (d1 - a) / (s * Memr[wp])
+ if (r < -lsigma || r > hsigma) {
+ Memr[resid+n1] = abs (r)
+ if (j < n1) {
+ dp2 = d[n1] + k
+ Memr[dp1] = Memr[dp2]
+ Memr[dp2] = d1
+ Memr[wp] = Memr[w+n1-1]
+ mp2 = m[n1] + k
+ l = Memi[mp1]
+ Memi[mp1] = Memi[mp2]
+ Memi[mp2] = l
+ j = j - 1
+ }
+ sum = sum - d1
+ n1 = n1 - 1
+ }
+ }
+ }
+ } else {
+ # Compute the sigma without scale correction.
+ s = 0.
+ do j = 1, n1
+ s = s + (Memr[d[j]+k] - a) ** 2
+ s = sqrt (s / (n1 - 1))
+
+ # Reject pixels. Save the residuals and data values.
+ if (s > 0.) {
+ for (j=1; j<=n1; j=j+1) {
+ dp1 = d[j] + k
+ d1 = Memr[dp1]
+ r = (d1 - a) / s
+ if (r < -lsigma || r > hsigma) {
+ Memr[resid+n1] = abs (r)
+ if (j < n1) {
+ dp2 = d[n1] + k
+ Memr[dp1] = Memr[dp2]
+ Memr[dp2] = d1
+ if (keepids) {
+ mp1 = m[j] + k
+ mp2 = m[n1] + k
+ l = Memi[mp1]
+ Memi[mp1] = Memi[mp2]
+ Memi[mp2] = l
+ }
+ j = j - 1
+ }
+ sum = sum - d1
+ n1 = n1 - 1
+ }
+ }
+ }
+ }
+
+ # Recompute the average.
+ if (n1 > 1)
+ a = sum / n1
+ } until (n1 == n2 || n1 <= max (2, maxkeep))
+
+ # If too many pixels are rejected add some back.
+ # All pixels with equal residuals are added back.
+ if (n1 < maxkeep) {
+ nk = maxkeep
+ if (doscale1) {
+ for (j=n1+1; j<=nk; j=j+1) {
+ dp1 = d[j] + k
+ mp1 = m[j] + k
+ r = Memr[resid+j]
+ jj = 0
+ do l = j+1, n2 {
+ s = Memr[resid+l]
+ if (s < r + TOL) {
+ if (s > r - TOL)
+ jj = jj + 1
+ else {
+ jj = 0
+ Memr[resid+l] = r
+ r = s
+ dp2 = d[l] + k
+ d1 = Memr[dp1]
+ Memr[dp1] = Memr[dp2]
+ Memr[dp2] = d1
+ mp2 = m[l] + k
+ s = Memi[mp1]
+ Memi[mp1] = Memi[mp2]
+ Memi[mp2] = s
+ }
+ }
+ }
+ sum = sum + Memr[dp1]
+ n1 = n1 + 1
+ nk = max (nk, j+jj)
+ }
+ } else {
+ for (j=n1+1; j<=nk; j=j+1) {
+ dp1 = d[j] + k
+ r = Memr[resid+j]
+ jj = 0
+ do l = j+1, n2 {
+ s = Memr[resid+l]
+ if (s < r + TOL) {
+ if (s > r - TOL)
+ jj = jj + 1
+ else {
+ jj = 0
+ Memr[resid+l] = r
+ r = s
+ dp2 = d[l] + k
+ d1 = Memr[dp1]
+ Memr[dp1] = Memr[dp2]
+ Memr[dp2] = d1
+ if (keepids) {
+ mp1 = m[j] + k
+ mp2 = m[l] + k
+ s = Memi[mp1]
+ Memi[mp1] = Memi[mp2]
+ Memi[mp2] = s
+ }
+ }
+ }
+ }
+ sum = sum + Memr[dp1]
+ n1 = n1 + 1
+ nk = max (nk, j+jj)
+ }
+ }
+
+ # Recompute the average.
+ if (n1 > 1)
+ a = sum / n1
+ }
+
+ # Save the average if needed.
+ n[i] = n1
+ if (!docombine) {
+ if (n1 > 0)
+ average[i] = a
+ else
+ average[i] = blank
+ }
+ }
+
+ # Check if the data flag has to be reset for rejected pixels
+ if (dflag == D_ALL) {
+ do i = 1, npts {
+ if (n[i] != nin) {
+ dflag = D_MIX
+ break
+ }
+ }
+ }
+
+ call sfree (sp)
+end
+
+
+# IC_MSIGCLIP -- Reject pixels using sigma clipping about the median
+
+procedure ic_msigclipr (d, m, n, scales, zeros, nimages, npts, median)
+
+pointer d[nimages] # Data pointers
+pointer m[nimages] # Image id pointers
+int n[npts] # Number of good pixels
+real scales[nimages] # Scales
+real zeros[nimages] # Zeros
+int nimages # Number of images
+int npts # Number of output points per line
+real median[npts] # Median
+
+int i, j, k, l, id, n1, n2, n3, nl, nh, nin, maxkeep
+real r, s
+pointer sp, resid, w, mp1, mp2
+real med, one
+data one /1.0/
+
+include "../icombine.com"
+
+begin
+ # If there are insufficient pixels go on to the combining
+ if (nkeep < 0)
+ maxkeep = max (0, nimages + nkeep)
+ else
+ maxkeep = min (nimages, nkeep)
+ if (nimages < max (MINCLIP, maxkeep+1) || dflag == D_NONE) {
+ docombine = true
+ return
+ }
+
+ # Save the residuals and sigma scaling corrections if needed.
+ call smark (sp)
+ call salloc (resid, nimages+1, TY_REAL)
+ if (doscale1)
+ call salloc (w, nimages, TY_REAL)
+
+ # Compute median and sigma and iteratively clip.
+ nin = n[1]
+ do i = 1, npts {
+ k = i - 1
+ n1 = n[i]
+ if (nkeep < 0)
+ maxkeep = max (0, n1 + nkeep)
+ else
+ maxkeep = min (n1, nkeep)
+ nl = 1
+ nh = n1
+
+ repeat {
+ n2 = n1
+ n3 = nl + n1 / 2
+
+ if (n1 == 0)
+ med = blank
+ else if (mod (n1, 2) == 0)
+ med = (Memr[d[n3-1]+k] + Memr[d[n3]+k]) / 2.
+ else
+ med = Memr[d[n3]+k]
+
+ if (n1 >= max (MINCLIP, maxkeep+1)) {
+ if (doscale1) {
+ # Compute the sigma with scaling correction.
+ s = 0.
+ do j = nl, nh {
+ l = Memi[m[j]+k]
+ r = sqrt (max (one, (med + zeros[l]) / scales[l]))
+ s = s + ((Memr[d[j]+k] - med) / r) ** 2
+ Memr[w+j-1] = r
+ }
+ s = sqrt (s / (n1 - 1))
+
+ # Reject pixels and save the residuals.
+ if (s > 0.) {
+ for (; nl <= n2; nl = nl + 1) {
+ r = (med - Memr[d[nl]+k]) / (s * Memr[w+nl-1])
+ if (r <= lsigma)
+ break
+ Memr[resid+nl] = r
+ n1 = n1 - 1
+ }
+ for (; nh >= nl; nh = nh - 1) {
+ r = (Memr[d[nh]+k] - med) / (s * Memr[w+nh-1])
+ if (r <= hsigma)
+ break
+ Memr[resid+nh] = r
+ n1 = n1 - 1
+ }
+ }
+ } else {
+ # Compute the sigma without scaling correction.
+ s = 0.
+ do j = nl, nh
+ s = s + (Memr[d[j]+k] - med) ** 2
+ s = sqrt (s / (n1 - 1))
+
+ # Reject pixels and save the residuals.
+ if (s > 0.) {
+ for (; nl <= n2; nl = nl + 1) {
+ r = (med - Memr[d[nl]+k]) / s
+ if (r <= lsigma)
+ break
+ Memr[resid+nl] = r
+ n1 = n1 - 1
+ }
+ for (; nh >= nl; nh = nh - 1) {
+ r = (Memr[d[nh]+k] - med) / s
+ if (r <= hsigma)
+ break
+ Memr[resid+nh] = r
+ n1 = n1 - 1
+ }
+ }
+ }
+ }
+ } until (n1 == n2 || n1 < max (MINCLIP, maxkeep+1))
+
+ # If too many pixels are rejected add some back.
+ # All pixels with equal residuals are added back.
+ while (n1 < maxkeep) {
+ if (nl == 1)
+ nh = nh + 1
+ else if (nh == n[i])
+ nl = nl - 1
+ else {
+ r = Memr[resid+nl-1]
+ s = Memr[resid+nh+1]
+ if (r < s) {
+ nl = nl - 1
+ r = r + TOL
+ if (s <= r)
+ nh = nh + 1
+ if (nl > 1) {
+ if (Memr[resid+nl-1] <= r)
+ nl = nl - 1
+ }
+ } else {
+ nh = nh + 1
+ s = s + TOL
+ if (r <= s)
+ nl = nl - 1
+ if (nh < n2) {
+ if (Memr[resid+nh+1] <= s)
+ nh = nh + 1
+ }
+ }
+ }
+ n1 = nh - nl + 1
+ }
+
+ # Only set median and reorder if needed
+ n[i] = n1
+ if (n1 > 0 && nl > 1 && (combine != MEDIAN || grow >= 1.)) {
+ j = max (nl, n1 + 1)
+ if (keepids) {
+ do l = 1, min (n1, nl-1) {
+ Memr[d[l]+k] = Memr[d[j]+k]
+ if (grow >= 1.) {
+ mp1 = m[l] + k
+ mp2 = m[j] + k
+ id = Memi[mp1]
+ Memi[mp1] = Memi[mp2]
+ Memi[mp2] = id
+ } else
+ Memi[m[l]+k] = Memi[m[j]+k]
+ j = j + 1
+ }
+ } else {
+ do l = 1, min (n1, nl - 1) {
+ Memr[d[l]+k] = Memr[d[j]+k]
+ j = j + 1
+ }
+ }
+ }
+
+ if (combine == MEDIAN)
+ median[i] = med
+ }
+
+ # Check if data flag needs to be reset for rejected pixels
+ if (dflag == D_ALL) {
+ do i = 1, npts {
+ if (n[i] != nin) {
+ dflag = D_MIX
+ break
+ }
+ }
+ }
+
+ # Flag that the median has been computed.
+ if (combine == MEDIAN)
+ docombine = false
+ else
+ docombine = true
+
+ call sfree (sp)
+end
+
+# IC_ASIGCLIP -- Reject pixels using sigma clipping about the average
+# The initial average rejects the high and low pixels. A correction for
+# different scalings of the images may be made. Weights are not used.
+
+procedure ic_asigclipd (d, m, n, scales, zeros, nimages, npts, average)
+
+pointer d[nimages] # Data pointers
+pointer m[nimages] # Image id pointers
+int n[npts] # Number of good pixels
+real scales[nimages] # Scales
+real zeros[nimages] # Zeros
+int nimages # Number of images
+int npts # Number of output points per line
+double average[npts] # Average
+
+int i, j, k, l, jj, n1, n2, nin, nk, maxkeep
+double d1, low, high, sum, a, s, r, one
+data one /1.0D0/
+pointer sp, resid, w, wp, dp1, dp2, mp1, mp2
+
+include "../icombine.com"
+
+begin
+ # If there are insufficient pixels go on to the combining
+ if (nkeep < 0)
+ maxkeep = max (0, nimages + nkeep)
+ else
+ maxkeep = min (nimages, nkeep)
+ if (nimages < max (MINCLIP, maxkeep+1) || dflag == D_NONE) {
+ docombine = true
+ return
+ }
+
+ # Flag whether returned average needs to be recomputed.
+ if (dowts || combine != AVERAGE)
+ docombine = true
+ else
+ docombine = false
+
+ # Save the residuals and the sigma scaling corrections if needed.
+ call smark (sp)
+ call salloc (resid, nimages+1, TY_REAL)
+ if (doscale1)
+ call salloc (w, nimages, TY_REAL)
+
+ # Do sigma clipping.
+ nin = n[1]
+ do i = 1, npts {
+ k = i - 1
+ n1 = n[i]
+ if (nkeep < 0)
+ maxkeep = max (0, n1 + nkeep)
+ else
+ maxkeep = min (n1, nkeep)
+
+ # If there are not enough pixels simply compute the average.
+ if (n1 < max (3, maxkeep)) {
+ if (!docombine) {
+ if (n1 == 0)
+ average[i] = blank
+ else {
+ sum = Memd[d[1]+k]
+ do j = 2, n1
+ sum = sum + Memd[d[j]+k]
+ average[i] = sum / n1
+ }
+ }
+ next
+ }
+
+ # Compute average with the high and low rejected.
+ low = Memd[d[1]+k]
+ high = Memd[d[2]+k]
+ if (low > high) {
+ d1 = low
+ low = high
+ high = d1
+ }
+ sum = 0.
+ do j = 3, n1 {
+ d1 = Memd[d[j]+k]
+ if (d1 < low) {
+ sum = sum + low
+ low = d1
+ } else if (d1 > high) {
+ sum = sum + high
+ high = d1
+ } else
+ sum = sum + d1
+ }
+ a = sum / (n1 - 2)
+ sum = sum + low + high
+
+ # Iteratively reject pixels and compute the final average if needed.
+ # Compact the data and keep track of the image IDs if needed.
+
+ repeat {
+ n2 = n1
+ if (doscale1) {
+ # Compute sigma corrected for scaling.
+ s = 0.
+ wp = w - 1
+ do j = 1, n1 {
+ dp1 = d[j] + k
+ mp1 = m[j] + k
+ wp = wp + 1
+
+ d1 = Memd[dp1]
+ l = Memi[mp1]
+ r = sqrt (max (one, (a + zeros[l]) / scales[l]))
+ s = s + ((d1 - a) / r) ** 2
+ Memr[wp] = r
+ }
+ s = sqrt (s / (n1 - 1))
+
+ # Reject pixels. Save the residuals and data values.
+ wp = w - 1
+ if (s > 0.) {
+ for (j=1; j<=n1; j=j+1) {
+ dp1 = d[j] + k
+ mp1 = m[j] + k
+ wp = wp + 1
+
+ d1 = Memd[dp1]
+ r = (d1 - a) / (s * Memr[wp])
+ if (r < -lsigma || r > hsigma) {
+ Memr[resid+n1] = abs (r)
+ if (j < n1) {
+ dp2 = d[n1] + k
+ Memd[dp1] = Memd[dp2]
+ Memd[dp2] = d1
+ Memr[wp] = Memr[w+n1-1]
+ mp2 = m[n1] + k
+ l = Memi[mp1]
+ Memi[mp1] = Memi[mp2]
+ Memi[mp2] = l
+ j = j - 1
+ }
+ sum = sum - d1
+ n1 = n1 - 1
+ }
+ }
+ }
+ } else {
+ # Compute the sigma without scale correction.
+ s = 0.
+ do j = 1, n1
+ s = s + (Memd[d[j]+k] - a) ** 2
+ s = sqrt (s / (n1 - 1))
+
+ # Reject pixels. Save the residuals and data values.
+ if (s > 0.) {
+ for (j=1; j<=n1; j=j+1) {
+ dp1 = d[j] + k
+ d1 = Memd[dp1]
+ r = (d1 - a) / s
+ if (r < -lsigma || r > hsigma) {
+ Memr[resid+n1] = abs (r)
+ if (j < n1) {
+ dp2 = d[n1] + k
+ Memd[dp1] = Memd[dp2]
+ Memd[dp2] = d1
+ if (keepids) {
+ mp1 = m[j] + k
+ mp2 = m[n1] + k
+ l = Memi[mp1]
+ Memi[mp1] = Memi[mp2]
+ Memi[mp2] = l
+ }
+ j = j - 1
+ }
+ sum = sum - d1
+ n1 = n1 - 1
+ }
+ }
+ }
+ }
+
+ # Recompute the average.
+ if (n1 > 1)
+ a = sum / n1
+ } until (n1 == n2 || n1 <= max (2, maxkeep))
+
+ # If too many pixels are rejected add some back.
+ # All pixels with equal residuals are added back.
+ if (n1 < maxkeep) {
+ nk = maxkeep
+ if (doscale1) {
+ for (j=n1+1; j<=nk; j=j+1) {
+ dp1 = d[j] + k
+ mp1 = m[j] + k
+ r = Memr[resid+j]
+ jj = 0
+ do l = j+1, n2 {
+ s = Memr[resid+l]
+ if (s < r + TOL) {
+ if (s > r - TOL)
+ jj = jj + 1
+ else {
+ jj = 0
+ Memr[resid+l] = r
+ r = s
+ dp2 = d[l] + k
+ d1 = Memd[dp1]
+ Memd[dp1] = Memd[dp2]
+ Memd[dp2] = d1
+ mp2 = m[l] + k
+ s = Memi[mp1]
+ Memi[mp1] = Memi[mp2]
+ Memi[mp2] = s
+ }
+ }
+ }
+ sum = sum + Memd[dp1]
+ n1 = n1 + 1
+ nk = max (nk, j+jj)
+ }
+ } else {
+ for (j=n1+1; j<=nk; j=j+1) {
+ dp1 = d[j] + k
+ r = Memr[resid+j]
+ jj = 0
+ do l = j+1, n2 {
+ s = Memr[resid+l]
+ if (s < r + TOL) {
+ if (s > r - TOL)
+ jj = jj + 1
+ else {
+ jj = 0
+ Memr[resid+l] = r
+ r = s
+ dp2 = d[l] + k
+ d1 = Memd[dp1]
+ Memd[dp1] = Memd[dp2]
+ Memd[dp2] = d1
+ if (keepids) {
+ mp1 = m[j] + k
+ mp2 = m[l] + k
+ s = Memi[mp1]
+ Memi[mp1] = Memi[mp2]
+ Memi[mp2] = s
+ }
+ }
+ }
+ }
+ sum = sum + Memd[dp1]
+ n1 = n1 + 1
+ nk = max (nk, j+jj)
+ }
+ }
+
+ # Recompute the average.
+ if (n1 > 1)
+ a = sum / n1
+ }
+
+ # Save the average if needed.
+ n[i] = n1
+ if (!docombine) {
+ if (n1 > 0)
+ average[i] = a
+ else
+ average[i] = blank
+ }
+ }
+
+ # Check if the data flag has to be reset for rejected pixels
+ if (dflag == D_ALL) {
+ do i = 1, npts {
+ if (n[i] != nin) {
+ dflag = D_MIX
+ break
+ }
+ }
+ }
+
+ call sfree (sp)
+end
+
+
+# IC_MSIGCLIP -- Reject pixels using sigma clipping about the median
+
+procedure ic_msigclipd (d, m, n, scales, zeros, nimages, npts, median)
+
+pointer d[nimages] # Data pointers
+pointer m[nimages] # Image id pointers
+int n[npts] # Number of good pixels
+real scales[nimages] # Scales
+real zeros[nimages] # Zeros
+int nimages # Number of images
+int npts # Number of output points per line
+double median[npts] # Median
+
+int i, j, k, l, id, n1, n2, n3, nl, nh, nin, maxkeep
+real r, s
+pointer sp, resid, w, mp1, mp2
+double med, one
+data one /1.0D0/
+
+include "../icombine.com"
+
+begin
+ # If there are insufficient pixels go on to the combining
+ if (nkeep < 0)
+ maxkeep = max (0, nimages + nkeep)
+ else
+ maxkeep = min (nimages, nkeep)
+ if (nimages < max (MINCLIP, maxkeep+1) || dflag == D_NONE) {
+ docombine = true
+ return
+ }
+
+ # Save the residuals and sigma scaling corrections if needed.
+ call smark (sp)
+ call salloc (resid, nimages+1, TY_REAL)
+ if (doscale1)
+ call salloc (w, nimages, TY_REAL)
+
+ # Compute median and sigma and iteratively clip.
+ nin = n[1]
+ do i = 1, npts {
+ k = i - 1
+ n1 = n[i]
+ if (nkeep < 0)
+ maxkeep = max (0, n1 + nkeep)
+ else
+ maxkeep = min (n1, nkeep)
+ nl = 1
+ nh = n1
+
+ repeat {
+ n2 = n1
+ n3 = nl + n1 / 2
+
+ if (n1 == 0)
+ med = blank
+ else if (mod (n1, 2) == 0)
+ med = (Memd[d[n3-1]+k] + Memd[d[n3]+k]) / 2.
+ else
+ med = Memd[d[n3]+k]
+
+ if (n1 >= max (MINCLIP, maxkeep+1)) {
+ if (doscale1) {
+ # Compute the sigma with scaling correction.
+ s = 0.
+ do j = nl, nh {
+ l = Memi[m[j]+k]
+ r = sqrt (max (one, (med + zeros[l]) / scales[l]))
+ s = s + ((Memd[d[j]+k] - med) / r) ** 2
+ Memr[w+j-1] = r
+ }
+ s = sqrt (s / (n1 - 1))
+
+ # Reject pixels and save the residuals.
+ if (s > 0.) {
+ for (; nl <= n2; nl = nl + 1) {
+ r = (med - Memd[d[nl]+k]) / (s * Memr[w+nl-1])
+ if (r <= lsigma)
+ break
+ Memr[resid+nl] = r
+ n1 = n1 - 1
+ }
+ for (; nh >= nl; nh = nh - 1) {
+ r = (Memd[d[nh]+k] - med) / (s * Memr[w+nh-1])
+ if (r <= hsigma)
+ break
+ Memr[resid+nh] = r
+ n1 = n1 - 1
+ }
+ }
+ } else {
+ # Compute the sigma without scaling correction.
+ s = 0.
+ do j = nl, nh
+ s = s + (Memd[d[j]+k] - med) ** 2
+ s = sqrt (s / (n1 - 1))
+
+ # Reject pixels and save the residuals.
+ if (s > 0.) {
+ for (; nl <= n2; nl = nl + 1) {
+ r = (med - Memd[d[nl]+k]) / s
+ if (r <= lsigma)
+ break
+ Memr[resid+nl] = r
+ n1 = n1 - 1
+ }
+ for (; nh >= nl; nh = nh - 1) {
+ r = (Memd[d[nh]+k] - med) / s
+ if (r <= hsigma)
+ break
+ Memr[resid+nh] = r
+ n1 = n1 - 1
+ }
+ }
+ }
+ }
+ } until (n1 == n2 || n1 < max (MINCLIP, maxkeep+1))
+
+ # If too many pixels are rejected add some back.
+ # All pixels with equal residuals are added back.
+ while (n1 < maxkeep) {
+ if (nl == 1)
+ nh = nh + 1
+ else if (nh == n[i])
+ nl = nl - 1
+ else {
+ r = Memr[resid+nl-1]
+ s = Memr[resid+nh+1]
+ if (r < s) {
+ nl = nl - 1
+ r = r + TOL
+ if (s <= r)
+ nh = nh + 1
+ if (nl > 1) {
+ if (Memr[resid+nl-1] <= r)
+ nl = nl - 1
+ }
+ } else {
+ nh = nh + 1
+ s = s + TOL
+ if (r <= s)
+ nl = nl - 1
+ if (nh < n2) {
+ if (Memr[resid+nh+1] <= s)
+ nh = nh + 1
+ }
+ }
+ }
+ n1 = nh - nl + 1
+ }
+
+ # Only set median and reorder if needed
+ n[i] = n1
+ if (n1 > 0 && nl > 1 && (combine != MEDIAN || grow >= 1.)) {
+ j = max (nl, n1 + 1)
+ if (keepids) {
+ do l = 1, min (n1, nl-1) {
+ Memd[d[l]+k] = Memd[d[j]+k]
+ if (grow >= 1.) {
+ mp1 = m[l] + k
+ mp2 = m[j] + k
+ id = Memi[mp1]
+ Memi[mp1] = Memi[mp2]
+ Memi[mp2] = id
+ } else
+ Memi[m[l]+k] = Memi[m[j]+k]
+ j = j + 1
+ }
+ } else {
+ do l = 1, min (n1, nl - 1) {
+ Memd[d[l]+k] = Memd[d[j]+k]
+ j = j + 1
+ }
+ }
+ }
+
+ if (combine == MEDIAN)
+ median[i] = med
+ }
+
+ # Check if data flag needs to be reset for rejected pixels
+ if (dflag == D_ALL) {
+ do i = 1, npts {
+ if (n[i] != nin) {
+ dflag = D_MIX
+ break
+ }
+ }
+ }
+
+ # Flag that the median has been computed.
+ if (combine == MEDIAN)
+ docombine = false
+ else
+ docombine = true
+
+ call sfree (sp)
+end