1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249
|
undocumented {
(random, GaloisField),
(random, QuotientRing),
(random, RingFamily),
}
doc ///
Node
Key
random
Headline
get a random object
Description
Text
This function can be used to get randomized objects of various sorts.
Subnodes
(random, ZZ, ZZ)
(random, Type)
(random, List)
(random, ZZ, Ideal)
(random, ZZ, Ring)
(random, Module, Module)
SeeAlso
setRandomSeed
Node
Key
(random, ZZ, ZZ)
(random, ZZ)
(random, RR, RR)
(random, RR)
Headline
get a random integer or real number
Synopsis
Usage
random(low, high)
random high
Inputs
low:{ZZ,RR}
high:{ZZ,RR}
Outputs
:ZZ
a random integer or real number of the same @TO precision@
Description
Text
If only @TT "high"@ is given, the output will be in the range @TT "[0, high)"@.
Example
random 57
random 10^50
tally apply(100, i -> random 7)
random 3.14
random 3p200
Text
If, in addition, @TT "low"@ is given, the output will be in the range @TT "[low, high]"@
Example
for i to 10 list random(100,200)
tally apply(100, i -> random(10,15))
random(10.,20.)
random(10p100,20p100)
SeeAlso
setRandomSeed
Node
Key
(random, Type)
Headline
get a random object of a type
Usage
random T
Inputs
T:Type
Height => ZZ
Outputs
:Thing
a random instance of the type @TT "T"@
Description
Text
If the @TT "Height"@ option specifies a number @TT "h"@ and @TT "T"@
is @TO "ZZ"@ then the integers returned are in the range @TT "[0, h)"@;
for @TO "QQ"@ the numerator and denominator are in the range @TT "[1, h]"@.
Example
random RR
random CC_100
tally for i to 100 list random GF 11
random GF(2,40)
SeeAlso
setRandomSeed
Node
Key
(random, ZZ, Ring)
(random, List, Ring)
[random, Height]
Headline
get a random homogeneous element from a graded ring
Usage
random(d, R)
Inputs
d:{ZZ,List} -- the degree or multi-degree to use
R:Ring
Outputs
:RingElement
a random homogeneous element of the ring @TT "R"@ of degree @TT "d"@
Description
Example
R = ZZ[x,y]
random(5, R)
R = GF(25, Variable => a)[x, y];
VerticalList for i to 6 list random(3, R)
Text
The length of @TT "d"@, if it's a list, should be the same as @TO2 (degreeLength, "degree rank")@ of $R$.
SeeAlso
setRandomSeed
Node
Key
(random, ZZ, Ideal)
(random, List, Ideal)
Headline
get a random homogeneous element from a graded ideal
Usage
random(d, I)
random(L, I)
Inputs
d:{ZZ,List} -- the degree, multi-degree, or a list of degrees
I:Ideal -- in a graded ring
Outputs
:{RingElement,List} -- homogeneous element(s) with prescribed degrees
Description
Text
This function produces one or more homogeneous elements of an ideal.
Example
S = ZZ/101[x, y]
I = ideal"x2, y2"
random(2, I)
random({2}, I)
random({2, 3}, I)
random({{2}, {3}}, I)
R = ZZ/101[x, y, z, Degrees => {{1,0}, {-1,1}, {0,1}}]
J = ideal"x2, y2, z2"
random({2, 2}, J)
random({{2, 2}}, J)
random(toList(3:{1, 1}), J)
Caveat
Note that in the single graded case, the input @TT "{d}"@ is treated as a multidegree
of length one rather than a list of length one, hence the output is one polynomial,
while @TT "{{d}}"@ is treated as a list containing a single multidegree of length one
and therefore the output is a list containing a single polynomial.
SeeAlso
(random, ZZ, Ring)
(random, List, Ring)
Node
Key
(random, List)
Headline
shuffle a list randomly
Usage
random L
Inputs
L:List
Outputs
:List
a new list containing the elements of @TT "L"@ in a shuffled random order
Description
Example
random toList (0 .. 12)
SeeAlso
setRandomSeed
///
document {
Key => {(random, Module, Module),[random, MaximalRank],[random, Density],[random, UpperTriangular]},
Headline => "make a random module map",
Usage => "f = random(F,G)",
Inputs => {
"F" => {"a free module"},
"G" => {"a free module"},
MaximalRank => {"whether to ensure that the resulting map has maximal rank: designed mostly
for use with matrices of numbers: for polynomial rings, returns inhomogeneous results"},
Density => RR => {"the proportion of entries to set"},
UpperTriangular => Boolean => {"whether to set just entries strictly above the diagonal"}
},
Outputs => {"f" => {"a random, graded, degree ", TT "0", " map, from ", TT "G", " to ", TT "F"}},
EXAMPLE lines ///
R = ZZ/101[x,y];
random(R^{1,2,3},R^{1,2,3})
random(ZZ^3,ZZ^6,MaximalRank=>true)
random(ZZ^3,ZZ^10,Density=>.3)
random(ZZ^6,ZZ^6,UpperTriangular=>true)
///,
Caveat => {
"Over a polynomial ring, specifying ", TT "MaximalRank=>true", " will yield a non-homogeneous matrix."
},
SeeAlso => {"setRandomSeed"}
}
document { Key => {(randomMutableMatrix, ZZ, ZZ, RR, ZZ),
[randomMutableMatrix,Dense],
randomMutableMatrix},
Headline => "a random mutable matrix of integers",
Usage => "randomMutableMatrix(nrows,ncols,zerof,max)",
Inputs => {
"nrows",
"ncols",
"zerof" => { "between 0 and 1" },
"max",
Dense => {"whether the encoding of the matrix should be dense or not: see ", TO MutableMatrix}
},
Outputs => {
{"a random mutable ", TT "nrows", " by ", TT "ncols", " matrix of integers.
The absolute value of the
entries is less than ", TT "max", ", and
the frequency of entries equal to zero is given by ", TT "zerof", "." }
},
"This function has been superseded by ", TO fillMatrix, ", which works over
more rings, is much faster for large matrices, and is more flexible.",
EXAMPLE lines ///
randomMutableMatrix(10,15,.9,100)
///,
SeeAlso => {mutableMatrix, fillMatrix, setRandomSeed, random}
}
document {
Headline => "fill a mutable matrix with random numbers",
Key => {fillMatrix,(fillMatrix, MutableMatrix),(fillMatrix, MutableMatrix, ZZ),
[fillMatrix, Height],[fillMatrix,Density],[fillMatrix,UpperTriangular]},
Usage => "fillMatrix M\nfillMatrix(M,n)",
BaseFunction => fillMatrix,
Inputs => {
"M"=>MutableMatrix,
"n" => ZZ => {"if specified, the maximum number of entries to replace"},
Density => RR => {"the fraction of entries of ", TT "M", " to be replaced, if ", TT "n", " is
not specified"},
UpperTriangular => Boolean => "whether to fill entries only above the diagonal",
Height => ZZ => "a bound on the absolute values of the generated random numbers"
},
Outputs => {"M"},
Consequences => {{ "some entries of M are replaced with randomly generated numbers, whose
size depends on the value of the option ", TT "Height" }},
EXAMPLE lines ///
printingPrecision = 2
fillMatrix(mutableMatrix(RR,5,10))
fillMatrix(mutableMatrix(ZZ,5,10),UpperTriangular=>true)
fillMatrix(mutableMatrix(QQ,5,10),Density=>.2,Height=>1000)
fillMatrix(mutableMatrix(ZZ,5,10),25,Height=>1000)
///,
SeeAlso => {setRandomSeed, random, mutableMatrix}
}
|