preImage -- Compute the preimage.

Synopsis

• Usage:

  preImage(A,v)

• Inputs:
  • A, a matrix, of full rank.
  • v, a vector, in target A.
• Outputs:
  • a vector, in source A.

Description

i1 : A=matrix {{1, 0}, {0, 1}, {-1, -1}}

o1 = | 1  0  |
     | 0  1  |
     | -1 -1 |

              3       2
o1 : Matrix ZZ  <-- ZZ

i2 : b=vector {-2,2,0}

o2 = | -2 |
     |  2 |
     |  0 |

       3
o2 : ZZ

i3 : v=preImage(A,b)

o3 = | -2 |
     |  2 |

       2
o3 : ZZ

i4 : A*v

o4 = | -2 |
     |  2 |
     |  0 |

       3
o4 : ZZ