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crossPolytope -- computes the d-dimensional crosspolytope with diameter 2s

Synopsis

Usage:

P = crossPolytope(d,s)
Inputs:
- d, an integer, strictly positive
- s, ZZ or QQ, positive (optional)
Outputs:
- P, a convex polyhedron

Description

The d-dimensional crossPolytope with diameter s is the convex hull of +/- s times the standard basis in QQ^d. If s is omitted it is set to 1.

i1 : P = crossPolytope(3,3/2)

o1 = P

o1 : Polyhedron

i2 : vertices P

o2 = | -3/2 3/2 0    0   0    0   |
     | 0    0   -3/2 3/2 0    0   |
     | 0    0   0    0   -3/2 3/2 |

              3       6
o2 : Matrix QQ  <-- QQ

Ways to use crossPolytope :

crossPolytope(ZZ)
crossPolytope(ZZ,QQ)
crossPolytope(ZZ,ZZ)

For the programmer

The object crossPolytope is a method function.