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PolyhedralSets[ZPolyhedralSets]

  

SamplePoint

  

return a sample point of a ZPolyhedralSet

 

Calling Sequence

Parameters

Description

Examples

References

Compatibility

Calling Sequence

SamplePoint(zpoly)

Parameters

zpoly

-

ZPolyhedralSet

Description

• 

SamplePoint(zpoly) returns a sample point of zpoly. If zpoly is empty, then an error is raised.

Examples

> 

with⁡PolyhedralSets:

> 

with⁡ZPolyhedralSets:

Create a Z-polyhedron in three-dimensional space.

> 

ineqs≔0≤−16+2⁢y+z,0≤−72+4⁢x+4⁢y+3⁢z,0≤2⁢y−z,0≤−24+4⁢x+4⁢y−3⁢z,0≤−4⁢x+4⁢y+3⁢z,0≤48−4⁢x+4⁢y−3⁢z,0≤48−4⁢x−4⁢y+3⁢z,0≤8−2⁢y+z,0≤−24+4⁢x−4⁢y+3⁢z,0≤24−2⁢y−z,0≤24+4⁢x−4⁢y−3⁢z,0≤96−4⁢x−4⁢y−3⁢z

ineqs≔0≤−16+2⁢y+z,0≤−72+4⁢x+4⁢y+3⁢z,0≤2⁢y−z,0≤−24+4⁢x+4⁢y−3⁢z,0≤−4⁢x+4⁢y+3⁢z,0≤48−4⁢x+4⁢y−3⁢z,0≤48−4⁢x−4⁢y+3⁢z,0≤8−2⁢y+z,0≤−24+4⁢x−4⁢y+3⁢z,0≤24−2⁢y−z,0≤24+4⁢x−4⁢y−3⁢z,0≤96−4⁢x−4⁢y−3⁢z

(1)
> 

L≔Lattice⁡Matrix⁡1,0,2,0,−1,1,0,0,2,Vector⁡0,0,1

L≔Lattice⁡1020−11002,001

(2)
> 

vars≔z,x,y

vars≔z,x,y

(3)
> 

zp≔ZPolyhedralSet⁡ineqs,vars,lattice=L

zp≔Relations:0≤2⁢y−z0≤−16+2⁢y+z0≤8−2⁢y+z0≤24−2⁢y−z0≤−4⁢x+4⁢y+3⁢z0≤−72+4⁢x+4⁢y+3⁢z0≤−24+4⁢x−4⁢y+3⁢z0≤−24+4⁢x+4⁢y−3⁢z0≤24+4⁢x−4⁢y−3⁢z0≤48−4⁢x−4⁢y+3⁢z0≤48−4⁢x+4⁢y−3⁢z0≤96−4⁢x−4⁢y−3⁢zVariables:z,x,yParameters:ParameterConstraints:Lattice:ZSpan1020−11002,,,001

(4)

Get a sample point from zp.

> 

SamplePoint⁡zp

z=10,x=9,y=7

(5)

Double-check that latter answer by enumerating the points of zp.

> 

EnumerateIntegerPoints⁡zp

x=9,y=5,z=6,x=9,y=7,z=6,x=8,y=5,z=7,x=9,y=5,z=7,x=10,y=5,z=7,x=8,y=7,z=7,x=9,y=7,z=7,x=10,y=7,z=7,x=7,y=5,z=8,x=8,y=5,z=8,x=9,y=5,z=8,x=10,y=5,z=8,x=11,y=5,z=8,x=7,y=7,z=8,x=8,y=7,z=8,x=9,y=7,z=8,x=10,y=7,z=8,x=11,y=7,z=8,x=8,y=5,z=9,x=9,y=5,z=9,x=10,y=5,z=9,x=8,y=7,z=9,x=9,y=7,z=9,x=10,y=7,z=9,x=9,y=5,z=10,x=9,y=7,z=10

(6)

References

  

Rachid Seghir, Vincent Loechner, and Benoı̂t Meister. "Integer affine transformations of parametric Z-polytopes and applications to loop nest optimization." Proceedings of TACO, Vol. 9(2):8:1–8:27, 2012.

  

Rui-Juan Jing and Marc Moreno Maza. "Computing the Integer Points of a Polyhedron, I: Algorithm." Proceedings of CASC 2017: 225-241, Springer.

  

Rui-Juan Jing and Marc Moreno Maza. "Computing the Integer Points of a Polyhedron, II: Complexity Estimates." Proceedings of CASC 2017: 242-256, Springer.

Compatibility

• 

The PolyhedralSets:-ZPolyhedralSets:-SamplePoint command was introduced in Maple 2023.

• 

For more information on Maple 2023 changes, see Updates in Maple 2023.

See Also

ZPolyhedralSets[IsEmpty]

ZPolyhedralSets[IsContained]

ZPolyhedralSets[IsIntegerPointOf]

ZPolyhedralSets[IntegerPointDecomposition]

ZPolyhedralSets[EnumerateIntegerPoints]

ZPolyhedralSets

PolyhedralSets