/** <summary>Compute the sample (unbiased estimator) standard deviation following:</summary>
*
* <remarks>
* Computing Deviations: Standard Accuracy
* Tony F. Chan and John Gregg Lewis
* Stanford University
* Communications of ACM September 1979 of Volume 22 the ACM Number 9
*
* The "two-pass" method from the paper; supposed to have better
* numerical properties than the textbook summation/sqrt. To me
* this looks like the textbook method, but I ain't no numerical
* methods guy.
* </remarks>
*/
public static double Stddev(int[] X)
{
int m = X.Length;
if (m <= 1)
{
return(0);
}
double xbar = EnumerableExtensions.Average(X);
double s2 = 0.0;
for (int i = 0; i < m; i++)
{
s2 += (X[i] - xbar) * (X[i] - xbar);
}
s2 = s2 / (m - 1);
return(Math.Sqrt(s2));
}
public void ShouldReturnValidResult()
{
// arrange
var source = Fixture.CreateMany <Length>(3).Select(e => new TestObject <Length>(e));
Func <TestObject <Length>, Length> selector = e => e.Property;
number expectedResultInMetres = source.Average(e => e.Property.Metres);
var expectedResultUnit = source.First().Property.Unit;
var expectedResult = new Length(expectedResultInMetres).Convert(expectedResultUnit);
// act
var result = EnumerableExtensions.Average(source, selector);
// assert
result.Metres.Should().BeApproximately(expectedResult.Metres);
result.Unit.Should().Be(expectedResult.Unit);
result.Value.Should().BeApproximately(expectedResult.Value);
}
public void ShouldReturnValidResult()
{
// arrange
var source = Fixture.CreateMany <SomeQuantity>(3).Select(e => new TestObject <SomeQuantity>(e));
Func <number, SomeUnit, SomeQuantity> factory = SomeQuantityFactory.Create;
Func <TestObject <SomeQuantity>, SomeQuantity> selector = e => e.Property;
number expectedResultInWatts = source.Average(e => e.Property.Value * e.Property.Unit.ValueInUnits);
var expectedResultUnit = source.First().Property.Unit;
var expectedResult = new SomeQuantity(expectedResultInWatts / expectedResultUnit.ValueInUnits, expectedResultUnit);
// act
var result = EnumerableExtensions.Average <TestObject <SomeQuantity>, SomeQuantity, SomeUnit>(source, factory, selector);
// assert
result.Value.Should().BeApproximately(expectedResult.Value);
result.Unit.Should().Be(expectedResult.Unit);
}
public static double avg(int[] X)
{
return(EnumerableExtensions.Average(EnumerableExtensions.DefaultIfEmpty(X, 0)));
}
public virtual string ToNotifyString()
{
ITokenStream input = _parser.TokenStream;
for (int i = 0; i < input.Count && _lastTokenConsumed != null && i <= _lastTokenConsumed.TokenIndex; i++)
{
IToken t = input.Get(i);
if (t.Channel != TokenChannels.Default)
{
numHiddenTokens++;
numHiddenCharsMatched += t.Text.Length;
}
}
numCharsMatched = _lastTokenConsumed.StopIndex + 1;
decisionMaxFixedLookaheads = Trim(decisionMaxFixedLookaheads, numFixedDecisions);
decisionMaxCyclicLookaheads = Trim(decisionMaxCyclicLookaheads, numCyclicDecisions);
StringBuilder buf = new StringBuilder();
buf.Append(Version);
buf.Append('\t');
buf.Append(_parser.GetType().Name);
buf.Append('\t');
buf.Append(numRuleInvocations);
buf.Append('\t');
buf.Append(maxRuleInvocationDepth);
buf.Append('\t');
buf.Append(numFixedDecisions);
buf.Append('\t');
buf.Append(EnumerableExtensions.Min(EnumerableExtensions.DefaultIfEmpty(decisionMaxFixedLookaheads, int.MaxValue)));
buf.Append('\t');
buf.Append(EnumerableExtensions.Max(EnumerableExtensions.DefaultIfEmpty(decisionMaxFixedLookaheads, int.MinValue)));
buf.Append('\t');
buf.Append(EnumerableExtensions.Average(EnumerableExtensions.DefaultIfEmpty(decisionMaxFixedLookaheads, 0)));
buf.Append('\t');
buf.Append(Stats.Stddev(decisionMaxFixedLookaheads));
buf.Append('\t');
buf.Append(numCyclicDecisions);
buf.Append('\t');
buf.Append(EnumerableExtensions.Min(EnumerableExtensions.DefaultIfEmpty(decisionMaxCyclicLookaheads, int.MaxValue)));
buf.Append('\t');
buf.Append(EnumerableExtensions.Max(EnumerableExtensions.DefaultIfEmpty(decisionMaxCyclicLookaheads, int.MinValue)));
buf.Append('\t');
buf.Append(EnumerableExtensions.Average(EnumerableExtensions.DefaultIfEmpty(decisionMaxCyclicLookaheads, 0)));
buf.Append('\t');
buf.Append(Stats.Stddev(decisionMaxCyclicLookaheads));
buf.Append('\t');
buf.Append(numBacktrackDecisions);
buf.Append('\t');
buf.Append(EnumerableExtensions.Min(EnumerableExtensions.DefaultIfEmpty(decisionMaxSynPredLookaheads, int.MaxValue)));
buf.Append('\t');
buf.Append(EnumerableExtensions.Max(EnumerableExtensions.DefaultIfEmpty(decisionMaxSynPredLookaheads, int.MinValue)));
buf.Append('\t');
buf.Append(EnumerableExtensions.Average(EnumerableExtensions.DefaultIfEmpty(decisionMaxSynPredLookaheads, 0)));
buf.Append('\t');
buf.Append(Stats.Stddev(decisionMaxSynPredLookaheads));
buf.Append('\t');
buf.Append(numSemanticPredicates);
buf.Append('\t');
buf.Append(_parser.TokenStream.Count);
buf.Append('\t');
buf.Append(numHiddenTokens);
buf.Append('\t');
buf.Append(numCharsMatched);
buf.Append('\t');
buf.Append(numHiddenCharsMatched);
buf.Append('\t');
buf.Append(numberReportedErrors);
buf.Append('\t');
buf.Append(numMemoizationCacheHits);
buf.Append('\t');
buf.Append(numMemoizationCacheMisses);
buf.Append('\t');
buf.Append(numGuessingRuleInvocations);
buf.Append('\t');
buf.Append(numMemoizationCacheEntries);
return(buf.ToString());
}