next | previous | forward | backward | up | top | index | toc | Macaulay2 web site
Macaulay2Doc :: random(Type)

random(Type) -- random element of a type

Synopsis

Description

Synopsis

  • Usage:
    random T
  • Inputs:
  • Outputs:
    • a random instance of the type T. If the Height option specifies a number h and T is ZZ and , then the integers returned are in the range 0 .. h-1; for QQ the numerator and denominator are in the range 1 .. h.
i1 : random RR

o1 = .758666467461991

o1 : RR (of precision 53)
i2 : random CC_100

o2 = .0486467826695887594883302854102+.703570429190131228582251826438*ii

o2 : CC (of precision 100)
i3 : tally for i to 100 list random GF 11

o3 = Tally{-1 => 4 }
           -2 => 13
           -3 => 15
           -4 => 12
           -5 => 11
           0 => 10
           1 => 13
           2 => 7
           3 => 4
           4 => 8
           5 => 4

o3 : Tally
i4 : random GF(2,40)

      38    37    36    34    33    32    28    24    21    20    19    17  
o4 = a   + a   + a   + a   + a   + a   + a   + a   + a   + a   + a   + a   +
     ------------------------------------------------------------------------
      16    15    14    12    8    5    4    3    2
     a   + a   + a   + a   + a  + a  + a  + a  + a  + 1

o4 : GF 1099511627776

Synopsis

  • Usage:
    random(d,R)
  • Inputs:
  • Outputs:
    • a random homogeneous element of the ring R of degree d
i5 : R = ZZ[x,y];
i6 : random(5,R)

       5     4      3 2     2 3       4     5
o6 = 8x  + 3x y + 9x y  + 8x y  + 8x*y  + 6y

o6 : R
i7 : R = GF(25,Variable=>a)[x,y];
i8 : VerticalList for i to 6 list random(3,R)

     {   3           2                2    3                }
o8 = {- x  + (a + 1)x y + (- a + 1)x*y  + y                 }
     {        3            2          2           3         }
     {(a + 1)x  + (2a + 1)x y - 2a*x*y  + (a - 2)y          }
     {         3       2               2           3        }
     {(2a + 2)x  + 2a*x y + (2a + 2)x*y  + (a - 2)y         }
     {   3    2               2     3                       }
     {- x  - x y + (2a + 2)x*y  + 2y                        }
     { 2         2           3                              }
     {x y + a*x*y  + (a + 1)y                               }
     {          3           2                 2            3}
     {(- a - 1)x  + (a - 1)x y + (- 2a - 2)x*y  + (2a - 2)y }
     {   3           2              2              3        }
     {a*x  + (a - 1)x y + (a - 1)x*y  + (- 2a - 1)y         }

o8 : VerticalList
The length of d, if it's a list, should be the same as degreeLength R.

See also