diff --git a/rogueviz/sag.cpp b/rogueviz/sag.cpp
index 161a4bb0..5c8f8666 100644
--- a/rogueviz/sag.cpp
+++ b/rogueviz/sag.cpp
@@ -9,6 +9,7 @@
 
 #include "dhrg/dhrg.h"
 #include <thread>
+#include "leastsquare.cpp"
 
 namespace rogueviz {
 
@@ -84,7 +85,7 @@ namespace sag {
   bool loglik_repeat;
 
   /* parameters for smMatch */
-  ld match_a = 1, match_b = 1;
+  ld match_a = 1, match_b = 0;
 
   /* parameters for smLogistic */
   dhrg::logistic lgsag(1, 1);
@@ -102,8 +103,6 @@ namespace sag {
   dhrg::logistic lgemb(1, 1);
   vector<hyperpoint> placement;  
 
-  void optimize_sag_loglik();
-
   string distance_file;
 
   void compute_dists() {
@@ -256,7 +255,9 @@ namespace sag {
         edgeinfo *ei = vd.edges[j].second;
         int t2 = vd.edges[j].first;
         if(sagid[t2] != -1) {
-          ld dist = sagdist[sid][sagid[t2]] - match_a / ei->weight2 - match_b;
+          ld cdist = sagdist[sid][sagid[t2]];
+          ld expect = match_a / ei->weight2 + match_b;
+          ld dist = cdist - expect;
           cost += dist * dist;
           }
         }
@@ -516,7 +517,7 @@ namespace sag {
     if(method == smLogistic) compute_loglik_tab();
     }
 
-  void optimize_sag_loglik() {
+  void optimize_sag_loglik_logistic() {
     vector<int> indist(max_sag_dist, 0);
     
     const int mul = 1;
@@ -575,6 +576,29 @@ namespace sag {
       }
     }
 
+  void optimize_sag_loglik_match() {
+    lsq::leastsquare_solver<2> lsqs;
+
+    for(auto& ei: sagedges) {
+      ld y = sagdist[sagid[ei.i]][sagid[ei.j]];
+      ld x = 1. / ei.weight;
+      lsqs.add_data({{x, 1}}, y);
+      }
+
+    array<ld, 2> solution = lsqs.solve();
+    match_a = solution[0];
+    match_b = solution[1];
+
+    println(hlog, "got a = ", match_a, " b = ", match_b);
+    if(method == smMatch)
+      prepare_graph();
+    }
+
+  void optimize_sag_loglik_auto() {
+    if(method == smLogistic) optimize_sag_loglik_logistic();
+    if(method == smMatch) optimize_sag_loglik_match();
+    }
+
   void disttable_add(ld dist, int qty0, int qty1) {
     using namespace dhrg;
     size_t i = dist * llcont_approx_prec;
@@ -1149,6 +1173,12 @@ int readArgs() {
     if(method == smLogistic) compute_loglik_tab();
     }
 
+  else if(argis("-sagmatch-ab")) {
+    shift(); sag::match_a = argf();
+    shift(); sag::match_b = argf();
+    if(method == smMatch) prepare_graph();
+    }
+
   else if(argis("-sagrt-auto")) {
     compute_auto_rt();
     }
@@ -1162,6 +1192,7 @@ int readArgs() {
     if(mtd == 4) method = smMatch, loglik_repeat = true;
     if(method == smLogistic)
       compute_loglik_tab();
+    if(method == smMatch) prepare_graph();
     }
 
   else if(argis("-sagminhelp")) {
@@ -1239,8 +1270,14 @@ int readArgs() {
     PHASE(3); shift(); auto_save = args();
     }
 // (6) output loglikelihood
-  else if(argis("-sagloglik")) {
-    sag::optimize_sag_loglik();
+  else if(argis("-sagloglik-l")) {
+    sag::optimize_sag_loglik_logistic();
+    }
+  else if(argis("-sagloglik-m")) {
+    sag::optimize_sag_loglik_match();
+    }
+  else if(argis("-sagloglik-a")) {
+    sag::optimize_sag_loglik_auto();
     }
   else if(argis("-sagmode")) {
     shift();