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C# Beta.GetMeanSquare方法代码示例

本文整理汇总了C#中Beta.GetMeanSquare方法的典型用法代码示例。如果您正苦于以下问题:C# Beta.GetMeanSquare方法的具体用法?C# Beta.GetMeanSquare怎么用?C# Beta.GetMeanSquare使用的例子?那么, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在Beta的用法示例。


在下文中一共展示了Beta.GetMeanSquare方法的1个代码示例,这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞,您的评价将有助于系统推荐出更棒的C#代码示例。

示例1: ProbTrueAverageConditional

		/// <summary>
		/// EP message to 'probTrue'
		/// </summary>
		/// <param name="sample">Incoming message from 'sample'. Must be a proper distribution.  If uniform, the result will be uniform.</param>
		/// <param name="probTrue">Incoming message from 'probTrue'.</param>
		/// <returns>The outgoing EP message to the 'probTrue' argument</returns>
		/// <remarks><para>
		/// The outgoing message is a distribution matching the moments of 'probTrue' as the random arguments are varied.
		/// The formula is <c>proj[p(probTrue) sum_(sample) p(sample) factor(sample,probTrue)]/p(probTrue)</c>.
		/// </para></remarks>
		/// <exception cref="ImproperMessageException"><paramref name="sample"/> is not a proper distribution</exception>
		public static Beta ProbTrueAverageConditional([SkipIfUniform] Bernoulli sample, Beta probTrue)
		{
			// this code is similar to DiscreteFromDirichletOp.PAverageConditional()
			if (probTrue.IsPointMass) {
				return Beta.Uniform();
			}
			if (sample.IsPointMass) {
				// shortcut
				return ProbTrueConditional(sample.Point);
			}
			if (!probTrue.IsProper()) throw new ImproperMessageException(probTrue);
			// q(x) is the distribution stored in this.X.
			// q(p) is the distribution stored in this.P.
			// f(x,p) is the factor.
			// Z = sum_x q(x) int_p f(x,p)*q(p) = q(false)*E[1-p] + q(true)*E[p]
			// Ef[p] = 1/Z sum_x q(x) int_p p*f(x,p)*q(p) = 1/Z (q(false)*E[p(1-p)] + q(true)*E[p^2])
			// Ef[p^2] = 1/Z sum_x q(x) int_p p^2*f(x,p)*q(p) = 1/Z (q(false)*E[p^2(1-p)] + q(true)*E[p^3])
			// var_f(p) = Ef[p^2] - Ef[p]^2
			double mo = probTrue.GetMean();
			double m2o = probTrue.GetMeanSquare();
			double pT = sample.GetProbTrue();
			double pF = sample.GetProbFalse();
			double Z = pF * (1 - mo) + pT * mo;
			double m = pF * (mo - m2o) + pT * m2o;
			m = m / Z;
			if (!Beta.AllowImproperSum) {
				if (pT < 0.5) {
					double inc = probTrue.TotalCount * (mo / m - 1);
					return new Beta(1, 1 + inc);
				} else {
					double inc = probTrue.TotalCount * ((1 - mo) / (1 - m) - 1);
					return new Beta(1 + inc, 1);
				}
			} else {
				double m3o = probTrue.GetMeanCube();
				double m2 = pF * (m2o - m3o) + pT * m3o;
				m2 = m2 / Z;
				Beta result = Beta.FromMeanAndVariance(m, m2 - m * m);
				result.SetToRatio(result, probTrue);
				return result;
			}
		}
开发者ID:prgoodwin,项目名称:HabilisX,代码行数:53,代码来源:BernoulliFromBeta.cs


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