At tbe IBM Pisa Scientific Center an interactive package has been developed under CP-67/CMS, which is particularly helpful when the data to be processed are time series. The interactive facilities of the operating system CP-67/CMS are strenghtened in such a way as to allow an easy interactive correction procedure during the execution of any command. The central file of time series data is available to be interactively shared among several users. Each user can also keep and use her/his own private series. Time series can have annual, semestral, quarterly or monthly entries. Arithmetic, algebraic and trigonometric operators, special operators - mean, variance, maximum, minimum, lagging, variation rate, first difference and selection of a part of a series - are supplied for interactive use. When applied to a time series, monadic operators - logarithm, exponential, etc - return a new series with different numeric data. When applied to two time series with the same periodicity (e.g. both with annual data, etc) dyadic operators - mm, subtraction, etc - return a new series referring to the period common to both the original series. Three interactive methods of estimation are supplied: ordinary least squares (OLS), two stage least squares (TSLS), limited information single equation (LISE). Correlation matrix and graphic plotting routines are provided. In addition it is easy for users with some experience of computer processing to insert special functions in the IMTS environment.
