Computing Profession

A statement which is similar to the NAMELIST statement of FORTRAN IV has been incorporated in the FORTRAN 63 compiler. The FORTRAN 63 implementation allows a greater flexibility and simplicity than the FORTRAN IV feature. The Hollerith names, the location, the made and the dimensions of a variable can be discovered by means of standard FORTRAN statements. Methods of using this information are illustrated in relation to general purpose data directed input and output routines; some other uses such as matrix manipulation are discussed.

WATFOR is an in-core, load-and-go compiler which has been implemented within the IBM 7040/44 operating system. FORTRAN IV was selected as the source language in order to achieve maximum language compatibility with other available compiling systems, in particular the IBM 7040/44 FORTRAN IV system. The principal advantage of the WATFOR compiler is that it translates FORTRAN IV programs at speeds of up to 100 statements per second. Since the compiler resides in core there is virtually no systems overhead, and hence large batches of “student” programs may be processed very efficiently. The compiler also provides extensive error diagnostics, during both the compilation and the execution phases of a program run. This feature makes the system attractive to both learners and learned users alike.

In this descriptive article an input code is presented which greatly simplifies data input to any linear programming solution routine, for subsequent use either as a predagogical device or for solving rather small LP problems. This latter (limited) use derives not at all from inherent limitations in the code itself, but from an efficiency evaluation: large LP problems would doubtless benefit from an input system more suited for bulk data handling than the input code described. From a user's standpoint, input appears almost exactly as a textbook presentation of the LP problem (limited only by a keypunch's inability to write subscripts, etc.). The input interpreter scans columnwise, thus no fixed format data preparation is required. The user may also, under very general requirements only, liberally use editorial comments throughout the input deck as an aid in identification, e.g., of row constraints. The article includes examples of input, output from a solution routine presently in use, and a skeleton flowchart of the input interpreter.