My first experience with symbolic manipulation was on main frame computers, using the FORTRAN and PL-1 versions of FORMAC. After I assembled my first microcomputer in 1981, I wrote a series of programs that I used extensively in subsequent research. The one that I have used most recently is called the Grad Student Rational Calculator and it is written in the MuLisp dialect of Lisp, popular in artificial intelligence programming. It can be compiled using a MuLISP-86 or MuLISP-87 compiler or the source code can be executed by a MuLisp interpreter.
To use the program, one writes a source file with a .in suffix. Any output which is produced is placed in a file with a .out suffix. The name Rational Calculator derives from the fact that only rational expressions are understood, and the appellation Grad Student derives from the fact that I made the software available to my graduate students. The principal feature that distinguishes the Grad Student Rational Calculator from other symbolic manipulation software is its fluency with respect to differential forms, which are extremely useful in connection with research in Einstein's theory of general relativity.
| GRAD STUDENT RATIONAL CALCULATOR MANUAL |
| schwarz.in | schwarz.out | kerr.in | kerr.out | ts.in | ts.out | np.in | np.out |
| gravity.in | VARIOUS TETRADS | natural.in | natural.out | null.in | null.out | ortho.in | ortho.out |
In February 2010 I am releasing for the first time the source code for the Grad Student Rational Calculator. This consists of six files, RATS0.LSP to RATS5.LSP. Without doubt some modification will be necessary to get these programs to work with versions of lisp other than MULISP-86 or MULISP-87 and on computers other than the computer I built in the 1980s or a Compaq Presario 4550 that I bought in 1998. It is my intention to try to develop a version that will function on UNIX-based machines such as my Apple Macintosh computer. Periodically I shall add more examples of IN-files and OUT-files that were involved in actual research projects in general relativity.
| RATS0.LSP | RATS1.LSP | RATS2.LSP | RATS3.LSP | RATS4.LSP | RATS5.LSP |
| Gravitational Research Projects |