diff --git a/chunkie/+chnk/+smoother/get_sigs.m b/chunkie/+chnk/+smoother/get_sigs.m
new file mode 100644
index 0000000..99672d9
--- /dev/null
+++ b/chunkie/+chnk/+smoother/get_sigs.m
@@ -0,0 +1,40 @@
+function [val,grad] = get_sigs(src_input,rt,sig0,dlam)
+
+        rc = src_input.centroids;
+        dlens = src_input.lengths;
+
+        [~,ns] = size(rc);
+        [~,nt] = size(rt);
+
+        xc = repmat(rc(1,:),nt,1);
+        yc = repmat(rc(2,:),nt,1);
+        dl = repmat(dlens,nt,1);
+
+        xt = repmat(rt(1,:).',1,ns);
+        yt = repmat(rt(2,:).',1,ns);
+
+        dx = xt-xc;
+        dy = yt-yc;
+        dr = sqrt(dx.^2+dy.^2);
+        dmin = min(dr,[],2);
+
+        dsigj = dl/dlam;
+        dexpn = exp(-(dr.^2-dmin.^2)./(2*sig0^2));
+        dsignum = sum(dsigj.*dexpn,2);
+        dsigden = sum(dexpn,2);
+        dsignumx = -dsigj.*dexpn.*(dx./sig0^2);
+        dsignumy = -dsigj.*dexpn.*(dy./sig0^2);
+        dsig = dsignum./dsigden;
+        dsigx = dsignumx./dsigden;
+        dsigy = dsignumy./dsigden;
+
+        val = dsig;
+
+        sz = size(dsig);
+        grad = zeros([sz,2]);
+        grad(:,:,1) = dsigx;
+        grad(:,:,2) = dsigy;
+        
+        grad = squeeze(grad);
+
+end
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