From 89b662b51373f0f466d62a65d3f0a164d1d31b1c Mon Sep 17 00:00:00 2001
From: Chris Dyer <cdyer@cs.cmu.edu>
Date: Fri, 27 Jan 2012 14:49:08 -0500
Subject: rename vest to dpmert (dynamic programming mert), rename variables
 and types to correspond to standard geometric concepts

---
 dpmert/line_optimizer.cc | 111 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 111 insertions(+)
 create mode 100644 dpmert/line_optimizer.cc

(limited to 'dpmert/line_optimizer.cc')

diff --git a/dpmert/line_optimizer.cc b/dpmert/line_optimizer.cc
new file mode 100644
index 00000000..49443fbe
--- /dev/null
+++ b/dpmert/line_optimizer.cc
@@ -0,0 +1,111 @@
+#include "line_optimizer.h"
+
+#include <limits>
+#include <algorithm>
+
+#include "sparse_vector.h"
+#include "ns.h"
+
+using namespace std;
+
+typedef ErrorSurface::const_iterator ErrorIter;
+
+// sort by increasing x-ints
+struct IntervalComp {
+  bool operator() (const ErrorIter& a, const ErrorIter& b) const {
+    return a->x < b->x;
+  }
+};
+
+double LineOptimizer::LineOptimize(
+    const EvaluationMetric* metric,
+    const vector<ErrorSurface>& surfaces,
+    const LineOptimizer::ScoreType type,
+    float* best_score,
+    const double epsilon) {
+  // cerr << "MIN=" << MINIMIZE_SCORE << " MAX=" << MAXIMIZE_SCORE << "  MINE=" << type << endl;
+  vector<ErrorIter> all_ints;
+  for (vector<ErrorSurface>::const_iterator i = surfaces.begin();
+       i != surfaces.end(); ++i) {
+    const ErrorSurface& surface = *i;
+    for (ErrorIter j = surface.begin(); j != surface.end(); ++j)
+      all_ints.push_back(j);
+  }
+  sort(all_ints.begin(), all_ints.end(), IntervalComp());
+  double last_boundary = all_ints.front()->x;
+  SufficientStats acc;
+  float& cur_best_score = *best_score;
+  cur_best_score = (type == MAXIMIZE_SCORE ?
+    -numeric_limits<float>::max() : numeric_limits<float>::max());
+  bool left_edge = true;
+  double pos = numeric_limits<double>::quiet_NaN();
+  for (vector<ErrorIter>::iterator i = all_ints.begin();
+       i != all_ints.end(); ++i) {
+    const ErrorSegment& seg = **i;
+    if (seg.x - last_boundary > epsilon) {
+      float sco = metric->ComputeScore(acc);
+      if ((type == MAXIMIZE_SCORE && sco > cur_best_score) ||
+          (type == MINIMIZE_SCORE && sco < cur_best_score) ) {
+        cur_best_score = sco;
+	if (left_edge) {
+	  pos = seg.x - 0.1;
+	  left_edge = false;
+	} else {
+	  pos = last_boundary + (seg.x - last_boundary) / 2;
+	}
+	//cerr << "NEW BEST: " << pos << "  (score=" << cur_best_score << ")\n";
+      }
+      // string xx = metric->DetailedScore(acc); cerr << "---- " << xx;
+      // cerr << "---- s=" << sco << "\n";
+      last_boundary = seg.x;
+    }
+    // cerr << "x-boundary=" << seg.x << "\n";
+    //string x2; acc.Encode(&x2); cerr << "   ACC: " << x2 << endl;
+    //string x1; seg.delta.Encode(&x1); cerr << " DELTA: " << x1 << endl;
+    acc += seg.delta;
+  }
+  float sco = metric->ComputeScore(acc);
+  if ((type == MAXIMIZE_SCORE && sco > cur_best_score) ||
+      (type == MINIMIZE_SCORE && sco < cur_best_score) ) {
+    cur_best_score = sco;
+    if (left_edge) {
+      pos = 0;
+    } else {
+      pos = last_boundary + 1000.0;
+    }
+  }
+  return pos;
+}
+
+void LineOptimizer::RandomUnitVector(const vector<int>& features_to_optimize,
+                                     SparseVector<double>* axis,
+                                     RandomNumberGenerator<boost::mt19937>* rng) {
+  axis->clear();
+  for (int i = 0; i < features_to_optimize.size(); ++i)
+    axis->set_value(features_to_optimize[i], rng->NextNormal(0.0,1.0));
+  (*axis) /= axis->l2norm();
+}
+
+void LineOptimizer::CreateOptimizationDirections(
+     const vector<int>& features_to_optimize,
+     int additional_random_directions,
+     RandomNumberGenerator<boost::mt19937>* rng,
+     vector<SparseVector<double> >* dirs
+     , bool include_orthogonal
+  ) {
+  dirs->clear();
+  typedef SparseVector<double> Dir;
+  vector<Dir> &out=*dirs;
+  int i=0;
+  if (include_orthogonal)
+    for (;i<features_to_optimize.size();++i) {
+      Dir d;
+      d.set_value(features_to_optimize[i],1.);
+      out.push_back(d);
+    }
+  out.resize(i+additional_random_directions);
+  for (;i<out.size();++i)
+     RandomUnitVector(features_to_optimize, &out[i], rng);
+  cerr << "Generated " << out.size() << " total axes to optimize along.\n";
+}
+
-- 
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