半Logistic分布

在限制中为 \(c\rightarrow\infty\) 对于广义半Logistic函数,我们定义了半Logistic函数 \(x\geq0.\) 另外, \(\left|X\right|\) 哪里 \(X\) 有物流配送。

\Begin{eqnarray*}f\Left(x\Right)&=&\frac{2e^{-x}}{\left(1+e^{-x}\right)^{2}}=\frac{1}{2}\mathrm{sech}^{2}\left(\frac{x}{2}\right)\\ F\Left(x\Right)&=&\frac{1-e^{-x}}{1+e^{-x}}=\tanh\left(\frac{x}{2}\right)\\ G\Left(Q\Right)&=&\log\left(\frac{1+q}{1-q}\right)=2\mathrm{arctanh}\left(q\right)\end{eqnarray*}
\[M\left(t\right)=1-t\psi_{0}\left(\frac{1}{2}-\frac{t}{2}\right)+t\psi_{0}\left(1-\frac{t}{2}\right)\]

哪里 \(\psi_m\) 是多伽马函数 \(\psi_m(z) = \frac{{d^{{m+1}}}}{{dz^{{m+1}}}} \log(\Gamma(z))\)

\[\mu_{n}^{\prime}=2\left(1-2^{1-n}\right)n!\zeta\left(n\right)\quad n\neq1\]
\BEGIN{eqnarray*}\mu{1}^{\Prime}&=&2\log\Left(2\Right)\\ \MU_{2}^{\Prime}&=&2\zeta\Left(2\右)=\frac{\pi^{2}}{3}\\ \MU_{3}^{\Prime}&=&9\zeta\Left(3\Right)\\ \MU_{4}^{\PRIME}&=&42\zeta\left(4\right)=\frac{7\pi^{4}}{15}\end{eqnarray*}
\BEGIN{eqnarray [}} h\left[X\right] & = & 2-\log\left(2\right)\\ & \approx & 1.3068528194400546906.\end{{eqnarray] }

实施: scipy.stats.halflogistic