Input

SHASTA understands two different input formats, infix and lisp. You must choose one input format when you launch SHASTA and you cannot change the input format during a session. Use -i fmt on the command line to select the desired input format, where fmt is either infix (the default) or lisp. The startup banner informs you of the selected input format.

• The infix format is the standard FORTRAN mathematical expression format with the additional feature that you can use both ^ and $\ast\ast$ for exponentiation. All statements must be terminated by a semicolon. In addition, the infix format allows SHASTA to read back the TEX that it generates, but do not expect it to understand TEX generated from anyone else, including you.
• The lisp format is the standard common LISP expression format, with the exception that the SHASTA function names are case-sensitive.

The following sample sessions show how to compute the rational kernel of the operator $(n+1)(n+2)E^2 -n(n+1)E - n$ in both the infix and lisp formats:

% shasta

                                                          /\    
      -----  it                                          /| \    
      \                 S H A S T A 1.0.0               / |  \    
       \                                               |   \  \   
       /                 A Sum^it server               |    |  \  
      /                                                /     \  \ 
      -----                                           /      |   \
                   Use ^D to terminate session       /       /    \


Sum^it - Copyright (c) 1994-2002, ETH Zurich, INRIA and M.Bronstein
Algebra Library - Copyright (c) 1994-2002, ETH Zurich, INRIA and M.Bronstein
Algebra Library - Copyright (c) 1998-2002, NAG Ltd., LIFL and M.Moreno Maza
Aldor Library - Copyright (c) 1998-2002, INRIA and M.Bronstein
GMP version: must be linked with GMP (Free Software Foundation)

Input format = infix
Independent variable = n
Shift = E

1 --> L := (n+1)*(n+2)*E^2 -n*(n+1)*E -n;
0:00:00.010 (gc = 0:00:00.000)

2 --> K := kernel(L);
0:00:00.190 (gc = 0:00:00.120)

% shasta -ilisp

                                                          /\    
      -----  it                                          /| \    
      \                 S H A S T A 1.0.0               / |  \    
       \                                               |   \  \   
       /                 A Sum^it server               |    |  \  
      /                                                /     \  \ 
      -----                                           /      |   \
                   Use ^D to terminate session       /       /    \


Sum^it - Copyright (c) 1994-2002, ETH Zurich, INRIA and M.Bronstein
Algebra Library - Copyright (c) 1994-2002, ETH Zurich, INRIA and M.Bronstein
Algebra Library - Copyright (c) 1998-2002, NAG Ltd., LIFL and M.Moreno Maza
Aldor Library - Copyright (c) 1998-2002, INRIA and M.Bronstein
GMP version: must be linked with GMP (Free Software Foundation)

Input format = lisp
Independent variable = n
Shift = E

1 --> (setq L (+ (* (+ n 1) (+ n 2) (^ E 2)) (- (* n (+ n 1) E)) (- n)))
0:00:00.010 (gc = 0:00:00.000)

2 --> (setq K (kernel L))
0:00:00.190 (gc = 0:00:00.120)