Efficient algorithm for generating spectra using line-by-line methods

A method for efficient generation of spectra using line-by-line approaches is presented. The only approximation is replacing the line shape function with an interpolation procedure, which makes the method independent of the line profile functional form. The computational savings for a large number of lines is proportional to the number of frequency points in the spectral range. Therefore, for large-scale problems the method can reduce the operation count by several orders of magnitude.