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##

The **compose** Command

The **compose** command is used to create vectors. It has two forms:

`compose `*vecname* *param = value* [...]

or`
`

compose *vecname* values *value* [...]

Both forms of this command create a new vector called *vecname*.
In the first form, the values in the vector are determined by the
parameters given, as described below. In the second form, indicated
by the keyword ```values`'', the given values are used to form the
vector.
In the first form, there are three groups of possible parameter sets.
The first set facilitates creation of uniform arrays. This set
contains the following parameters.

`start ` |
The value at which the vector should start |

`stop ` |
The value at which the vector should end |

`step ` |
The difference between successive elements |

`lin ` |
The number of points, linearly spaced |

`log ` |
The number of points, logarithmically spaced |

`dec ` |
The number of points per decade, logarithmically spaced |

The words ```len`'' and ```length`'' are synonyms for ```lin`''. A subset of these parameters that provides the information
needed is sufficient. If all four are given, the point count and step
value must be consistent or the command will fail. The parameter `start` defaults to zero, unless implicitly set by other parameters.
The `stop` and `step` have no defaults and must be supplied
unless implied by other parameters. If the `lin` parameter is not
given, the other parameters determine the vector length.

The second parameter group generates Gaussian random values.

`gauss ` |
The number of points in the gaussian distribution |

`mean ` |
The mean value for the gaussian distribution |

`sd ` |
The standard deviation for the gaussian distribution |

The `gauss` parameter is required, `sd` defaults to 1.0, and
`mean` defaults to 0. The random number sequences can be reset by
calling the **seed** command.

The third parameter group generates uniform random values.

`random ` |
The number of randomly selected points |

`center ` |
Where to center the range of points |

`span ` |
The size of the range of points |

The `random` parameter is required, `span` defaults to 2.0,
and `center` defaults to 0. The random number sequences can be
reset by calling the **seed** command.

** Next:** The cross Command
** Up:** Data Manipulation Commands
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Stephen R. Whiteley
2019-06-03