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Simplify envelope binary search and uses of it

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This commit is contained in:
Paul Licameli 2017-05-04 00:11:36 -04:00
parent 30e67bcb8e
commit 7ad910c0a6
1 changed files with 27 additions and 40 deletions
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67
src/Envelope.cpp
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@ -1049,21 +1049,17 @@ double Envelope::GetValue(double t) const
} }
// relative time // relative time
/// @param Lo returns last index at or before this time. /// @param Lo returns last index at or before this time, maybe -1
/// @param Hi returns first index after this time. /// @param Hi returns first index after this time, maybe past the end
void Envelope::BinarySearchForTime( int &Lo, int &Hi, double t ) const void Envelope::BinarySearchForTime( int &Lo, int &Hi, double t ) const
{ {
Lo = 0;
Hi = mEnv.size() - 1;
// JC: Do we have a problem if the envelope only has one point??
wxASSERT(Hi > Lo);
// Optimizations for the usual pattern of repeated calls with // Optimizations for the usual pattern of repeated calls with
// small increases of t. // small increases of t.
{ {
if (mSearchGuess >= 0 && mSearchGuess < (int)(mEnv.size()) - 1) { if (mSearchGuess >= 0 && mSearchGuess < mEnv.size()) {
if (t >= mEnv[mSearchGuess].GetT() && if (t >= mEnv[mSearchGuess].GetT() &&
t < mEnv[1 + mSearchGuess].GetT()) { (1 + mSearchGuess == mEnv.size() ||
t < mEnv[1 + mSearchGuess].GetT())) {
Lo = mSearchGuess; Lo = mSearchGuess;
Hi = 1 + mSearchGuess; Hi = 1 + mSearchGuess;
return; return;
@ -1071,9 +1067,10 @@ void Envelope::BinarySearchForTime( int &Lo, int &Hi, double t ) const
} }
++mSearchGuess; ++mSearchGuess;
if (mSearchGuess >= 0 && mSearchGuess < (int)(mEnv.size()) - 1) { if (mSearchGuess >= 0 && mSearchGuess < mEnv.size()) {
if (t >= mEnv[mSearchGuess].GetT() && if (t >= mEnv[mSearchGuess].GetT() &&
t < mEnv[1 + mSearchGuess].GetT()) { (1 + mSearchGuess == mEnv.size() ||
t < mEnv[1 + mSearchGuess].GetT())) {
Lo = mSearchGuess; Lo = mSearchGuess;
Hi = 1 + mSearchGuess; Hi = 1 + mSearchGuess;
return; return;
@ -1081,8 +1078,13 @@ void Envelope::BinarySearchForTime( int &Lo, int &Hi, double t ) const
} }
} }
Lo = -1;
Hi = mEnv.size();
// Invariants: Lo is not less than -1, Hi not more than size
while (Hi > (Lo + 1)) { while (Hi > (Lo + 1)) {
int mid = (Lo + Hi) / 2; int mid = (Lo + Hi) / 2;
// mid must be strictly between Lo and Hi, therefore a valid index
if (t < mEnv[mid].GetT()) if (t < mEnv[mid].GetT())
Hi = mid; Hi = mid;
else else
@ -1152,6 +1154,8 @@ void Envelope::GetValues(double *buffer, int bufferLen,
int lo,hi; int lo,hi;
BinarySearchForTime( lo, hi, t ); BinarySearchForTime( lo, hi, t );
// mEnv[0] is before t because of eliminations above, therefore lo >= 0
// mEnv[len - 1] is after t, therefore hi <= len - 1
tprev = mEnv[lo].GetT(); tprev = mEnv[lo].GetT();
tnext = mEnv[hi].GetT(); tnext = mEnv[hi].GetT();
@ -1203,38 +1207,21 @@ void Envelope::GetValues
// relative time // relative time
int Envelope::NumberOfPointsAfter(double t) const int Envelope::NumberOfPointsAfter(double t) const
{ {
if( t >= mEnv[mEnv.size()-1].GetT() ) int lo,hi;
return 0; BinarySearchForTime( lo, hi, t );
else if( t < mEnv[0].GetT() )
return mEnv.size();
else
{
int lo,hi;
BinarySearchForTime( lo, hi, t );
if( mEnv[hi].GetT() == t ) return mEnv.size() - hi;
return mEnv.size() - (hi+1);
else
return mEnv.size() - hi;
}
} }
// relative time // relative time
double Envelope::NextPointAfter(double t) const double Envelope::NextPointAfter(double t) const
{ {
if( mEnv[mEnv.size()-1].GetT() < t ) int lo,hi;
BinarySearchForTime( lo, hi, t );
if (hi >= mEnv.size())
return t; return t;
else if( t < mEnv[0].GetT() )
return mEnv[0].GetT();
else else
{ return mEnv[hi].GetT();
int lo,hi;
BinarySearchForTime( lo, hi, t );
if( mEnv[hi].GetT() == t )
return mEnv[hi+1].GetT();
else
return mEnv[hi].GetT();
}
} }
double Envelope::Average( double t0, double t1 ) const double Envelope::Average( double t0, double t1 ) const
@ -1363,7 +1350,7 @@ double Envelope::Integral( double t0, double t1 ) const
lastVal = mEnv[0].GetVal(); lastVal = mEnv[0].GetVal();
total += (lastT - t0) * lastVal; total += (lastT - t0) * lastVal;
} }
else if(t0 >= mEnv[count - 1].GetT()) // t0 following the last point else if(t0 >= mEnv[count - 1].GetT()) // t0 at or following the last point
{ {
return (t1 - t0) * mEnv[count - 1].GetVal(); return (t1 - t0) * mEnv[count - 1].GetVal();
} }
@ -1389,7 +1376,7 @@ double Envelope::Integral( double t0, double t1 ) const
double thisVal = InterpolatePoints(mEnv[i - 1].GetVal(), mEnv[i].GetVal(), (t1 - mEnv[i - 1].GetT()) / (mEnv[i].GetT() - mEnv[i - 1].GetT()), mDB); double thisVal = InterpolatePoints(mEnv[i - 1].GetVal(), mEnv[i].GetVal(), (t1 - mEnv[i - 1].GetT()) / (mEnv[i].GetT() - mEnv[i - 1].GetT()), mDB);
return total + IntegrateInterpolated(lastVal, thisVal, t1 - lastT, mDB); return total + IntegrateInterpolated(lastVal, thisVal, t1 - lastT, mDB);
} }
else // this point preceeds the end of the range else // this point precedes the end of the range
{ {
total += IntegrateInterpolated(lastVal, mEnv[i].GetVal(), mEnv[i].GetT() - lastT, mDB); total += IntegrateInterpolated(lastVal, mEnv[i].GetVal(), mEnv[i].GetT() - lastT, mDB);
lastT = mEnv[i].GetT(); lastT = mEnv[i].GetT();
@ -1426,7 +1413,7 @@ double Envelope::IntegralOfInverse( double t0, double t1 ) const
lastVal = mEnv[0].GetVal(); lastVal = mEnv[0].GetVal();
total += (lastT - t0) / lastVal; total += (lastT - t0) / lastVal;
} }
else if(t0 >= mEnv[count - 1].GetT()) // t0 following the last point else if(t0 >= mEnv[count - 1].GetT()) // t0 at or following the last point
{ {
return (t1 - t0) / mEnv[count - 1].GetVal(); return (t1 - t0) / mEnv[count - 1].GetVal();
} }
@ -1452,7 +1439,7 @@ double Envelope::IntegralOfInverse( double t0, double t1 ) const
double thisVal = InterpolatePoints(mEnv[i - 1].GetVal(), mEnv[i].GetVal(), (t1 - mEnv[i - 1].GetT()) / (mEnv[i].GetT() - mEnv[i - 1].GetT()), mDB); double thisVal = InterpolatePoints(mEnv[i - 1].GetVal(), mEnv[i].GetVal(), (t1 - mEnv[i - 1].GetT()) / (mEnv[i].GetT() - mEnv[i - 1].GetT()), mDB);
return total + IntegrateInverseInterpolated(lastVal, thisVal, t1 - lastT, mDB); return total + IntegrateInverseInterpolated(lastVal, thisVal, t1 - lastT, mDB);
} }
else // this point preceeds the end of the range else // this point precedes the end of the range
{ {
total += IntegrateInverseInterpolated(lastVal, mEnv[i].GetVal(), mEnv[i].GetT() - lastT, mDB); total += IntegrateInverseInterpolated(lastVal, mEnv[i].GetVal(), mEnv[i].GetT() - lastT, mDB);
lastT = mEnv[i].GetT(); lastT = mEnv[i].GetT();
@ -1492,7 +1479,7 @@ double Envelope::SolveIntegralOfInverse( double t0, double area ) const
area -= added; area -= added;
} }
} }
else if(t0 >= mEnv[count - 1].GetT()) // t0 following the last point else if(t0 >= mEnv[count - 1].GetT()) // t0 at or following the last point
{ {
if (area < 0) { if (area < 0) {
i = count - 2; i = count - 2;