... There are several ways in which the user can specify the convolving function, governed by the parameter convolvertype . ... convolvertype = `gaussian': the task reads the sigma value from the parameter of the same name. The convolver is truncated at 5 times sigma either side of the centre of the gaussian. convolvertype = `user': in this mode, the user can supply the convolver directly as a list of real numbers via the parameter convolver . ... colsmooth convolvertype=user convolver='0 0 1 0 0' . ...