1 files changed, 42 insertions, 0 deletions
diff --git a/noao/rv/rvidlines/iddoshift.x b/noao/rv/rvidlines/iddoshift.x
new file mode 100644
index 00000000..6e397455
--- /dev/null
+++ b/noao/rv/rvidlines/iddoshift.x
@@ -0,0 +1,42 @@
+include	"identify.h"
+
+# ID_DOSHIFT -- Minimize residuals by constant shift.
+
+procedure id_doshift (id, interactive)
+
+pointer	id			# ID pointer
+int	interactive		# Called interactively?
+
+int	i, j
+double	shft, delta, rms, id_fitpt()
+
+begin
+	shft = 0.
+	rms = 0.
+	j = 0
+	for (i=1; i <= ID_NFEATURES(id); i = i + 1) {
+	    if (IS_INDEFD (USER(id,i)) || WTS(id,i) == 0.)
+		next
+	    delta = USER(id,i) - id_fitpt (id, PIX(id,i))
+	    shft = shft + delta
+	    rms = rms + delta * delta
+	    j = j + 1
+	}
+
+	if (j > 0) {
+	    shft = shft / j
+	    rms = rms / j
+	    if (interactive == YES) {
+	        call printf ("%s%s: Coordinate shift=%5f, rms=%5f, npts=%3d\n")
+		    call pargstr (Memc[ID_IMAGE(id)])
+		    call pargstr (Memc[ID_SECTION(id)])
+		    call pargd (shft)
+		    call pargd (sqrt (rms - shft ** 2))
+		    call pargi (j)
+	    }
+	    ID_SHIFT(id) = ID_SHIFT(id) + shft
+	    ID_REDSHIFT(id) = 0.
+	    ID_NEWCV(id) = YES
+	    ID_NEWGRAPH(id) = YES
+	}
+end