f(x;\alpha,\beta,\sigma) &=& \beta\frac{\alpha}{2}\,e^{\alpha x+\frac{\alpha^2\sigma^2}{2}}\left[1-Erf\left(\frac{x+\alpha\sigma^2}{\sqrt{2}\sigma}\right)\right] \\ &+& \frac{1-\beta}{\sqrt{2\pi}\sigma}e^{-\frac{x^2}{2\sigma^2}}\\ | f(x;\alpha,\beta,\sigma) &=& \beta\frac{\alpha}{2}\,e^{\alpha x+\frac{\alpha^2\sigma^2}{2}}\left[1-Erf\left(\frac{x+\alpha\sigma^2}{\sqrt{2}\sigma}\right)\right] \\ &+& \frac{1-\beta}{\sqrt{2\pi}\sigma}e^{-\frac{x^2}{2\sigma^2}}\\ |