From d5a2a9c3bf18c1e414f79a757c1662fe422e2f5c Mon Sep 17 00:00:00 2001
From: Chris Dyer <cdyer@cs.cmu.edu>
Date: Mon, 16 Apr 2012 14:11:02 -0400
Subject: switch to log domain for matrix operations

---
 utils/logval.h | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

(limited to 'utils/logval.h')

diff --git a/utils/logval.h b/utils/logval.h
index 8a59d0b1..ec1f6acd 100644
--- a/utils/logval.h
+++ b/utils/logval.h
@@ -30,8 +30,6 @@ class LogVal {
   LogVal(init_minus_1) : s_(true),v_(0) {  }
   LogVal(init_1) : s_(),v_(0) {  }
   LogVal(init_0) : s_(),v_(LOGVAL_LOG0) {  }
-  explicit LogVal(int x) : s_(x<0), v_(s_ ? std::log(-x) : std::log(x)) {}
-  explicit LogVal(unsigned x) : s_(0), v_(std::log(x)) { }
   LogVal(double lnx,bool sign) : s_(sign),v_(lnx) {}
   LogVal(double lnx,init_lnx) : s_(),v_(lnx) {}
   static Self exp(T lnx) { return Self(lnx,false); }
@@ -126,7 +124,7 @@ class LogVal {
   }
 
   Self operator-() const {
-    return Self(v_,-s_);
+    return Self(v_,!s_);
   }
   void negate() { s_ = !s_; }
 
@@ -193,6 +191,15 @@ T log(const LogVal<T>& o) {
   return o.v_;
 }
 
+template<class T>
+LogVal<T> abs(const LogVal<T>& o) {
+  if (o.s_) {
+    LogVal<T> res = o;
+    res.s_ = false;
+    return res;
+  } else { return o; }
+}
+
 template <class T>
 LogVal<T> pow(const LogVal<T>& b, const T& e) {
   return b.pow(e);
-- 
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