The first one is the most basic PDF; namely the uniform distribution $$ \begin{equation} p(x) = \frac{1}{b-a}\theta(x-a)\theta(b-x), \tag{1} \end{equation} $$ with $$ \begin{equation*} \begin{array}{ll} \theta(x)=0 & x < 0 \\ \theta(x)=\frac{1}{b-a} & \in [a,b]. \end{array} \end{equation*} $$ The normal distribution with \( b=1 \) and \( a=0 \) is used to generate random numbers.