Remarks on Algorithm 332: Jacobi polynomials: Algorithm 344: student's t -distribution: Algorithm 351: modified Romberg quadrature: Algorithm 359: factoral analysis of variance

The classical exponential integral is defined bywhere the integral is to be interpreted as the Cauchy principal value.Except for the sign, it represents the natural extension of the function El(z) ~ f~ e-$ --at=-E,(-z), largzl< 3. z t to the negative real axis.The rational approximations and corresponding intervals used in this routine are: Eu,(x) --e~ I1