From 38b69871ae87506c21a6b53ba418139d24305590 Mon Sep 17 00:00:00 2001
From: Alexander Chemeris <Alexander.Chemeris@gmail.com>
Date: Fri, 17 Mar 2017 18:20:09 -0700
Subject: [PATCH] BitVector: Convert SoftVector from 0..1 to -1..+1 soft bits.

This makes code simpler and will allow us send -127..127 soft bits towards
osmo-bts instead of 0..255 bits.

Change-Id: I16ecc3d4c829dcf0f619ad995bc9d4a4ed8af0a4
---
 CommonLibs/BitVector.cpp | 20 ++++++++++----------
 CommonLibs/BitVector.h   |  6 +++---
 2 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/CommonLibs/BitVector.cpp b/CommonLibs/BitVector.cpp
index b77a4c4a..3b556b99 100644
--- a/CommonLibs/BitVector.cpp
+++ b/CommonLibs/BitVector.cpp
@@ -30,6 +30,7 @@
 #include <iostream>
 #include <stdio.h>
 #include <sstream>
+#include <math.h>
 
 using namespace std;
 
@@ -268,7 +269,7 @@ SoftVector::SoftVector(const BitVector& source)
 	resize(source.size());
 	for (size_t i=0; i<size(); i++) {
 		if (source.bit(i)) mStart[i]=1.0F;
-		else mStart[i]=0.0F;
+		else mStart[i]=-1.0F;
 	}
 }
 
@@ -278,7 +279,7 @@ BitVector SoftVector::sliced() const
 	size_t sz = size();
 	BitVector newSig(sz);
 	for (size_t i=0; i<sz; i++) {
-		if (mStart[i]>0.5F) newSig[i]=1;
+		if (mStart[i]>0.0F) newSig[i]=1;
 		else newSig[i] = 0;
 	}
 	return newSig;
@@ -291,8 +292,7 @@ float SoftVector::getEnergy(float *plow) const
 	int len = vec.size();
 	float avg = 0; float low = 1;
 	for (int i = 0; i < len; i++) {
-		float bit = vec[i];
-		float energy = 2*((bit < 0.5) ? (0.5-bit) : (bit-0.5));
+		float energy = fabsf(vec[i]);
 		if (energy < low) low = energy;
 		avg += energy/len;
 	}
@@ -304,12 +304,12 @@ float SoftVector::getEnergy(float *plow) const
 ostream& operator<<(ostream& os, const SoftVector& sv)
 {
 	for (size_t i=0; i<sv.size(); i++) {
-		if (sv[i]<0.25) os << "0";
-		else if (sv[i]<0.4) os << "o";
-		else if (sv[i]<0.5) os << ".";
-		else if (sv[i]>0.75) os << "1";
-		else if (sv[i]>0.6) os << "|";
-		else if (sv[i]>0.5) os << "'";
+		if (sv[i]<-0.5) os << "0";
+		else if (sv[i]<-0.25) os << "o";
+		else if (sv[i]<0.0) os << ".";
+		else if (sv[i]>0.5) os << "1";
+		else if (sv[i]>0.25) os << "|";
+		else if (sv[i]>0.0) os << "'";
 		else os << "-";
 	}
 	return os;
diff --git a/CommonLibs/BitVector.h b/CommonLibs/BitVector.h
index 7473c329..d2acb5f1 100644
--- a/CommonLibs/BitVector.h
+++ b/CommonLibs/BitVector.h
@@ -290,19 +290,19 @@ class SoftVector: public Vector<float> {
 	//@}
 
 	// How good is the SoftVector in the sense of the bits being solid?
-	// Result of 1 is perfect and 0 means all the bits were 0.5
+	// Result of 1 is perfect and 0 means all the bits were 0.0
 	// If plow is non-NULL, also return the lowest energy bit.
 	float getEnergy(float *low=0) const;
 
 	/** Fill with "unknown" values. */
-	void unknown() { fill(0.5F); }
+	void unknown() { fill(0.0F); }
 
 	/** Return a hard bit value from a given index by slicing. */
 	bool bit(size_t index) const
 	{
 		const float *dp = mStart+index;
 		assert(dp<mEnd);
-		return (*dp)>0.5F;
+		return (*dp)>0.0F;
 	}
 
 	/** Slice the whole signal into bits. */