# Physics307L:People/Mondragon/Poisson/Programming/CommandReference

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**Command reference** taken from the documentation for Octave 3.0
Copyright © 1996, 1997, 1999, 2000, 2001, 2002, 2005, 2006, 2007 John W. Eaton.

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## Contents |

## diary

**diary** *options*

- Create a list of all commands and the output they produce, mixed together just as you see them on your terminal. Valid options are:

- on
- Start recording your session in a file called ‘diary’ in your current working directory.

- off
- Stop recording your session in the diary file.

- file
- Record your session in the file named file.

- Without any arguments, diary toggles the current diary state.

## poissrnd

**poissrnd** (*lambda*, *r*, *c*)

- Return an
*r*by*c*matrix of random samples from the Poisson distribution with parameter*lambda*, which must be a scalar or of size*r*by*c*.

- If
*r*and*c*are omitted, the size of the result matrix is the size of*lambda*.

## values

**values** (*x*)

- Return the different values in a column vector, arranged in ascending order.

- As an example, values([1, 2, 3, 1]) returns the vector [1, 2, 3].

## range

**range** (*x*, *dim*)

- If
*x*is a vector, return the range, i.e., the difference between the maximum and the minimum, of the input data.

- If
*x*is a matrix, do the above for each column of*x*.

- If the optional argument
*dim*is supplied, work along dimension*dim*.

## max

**max** (*x*, *y*, *dim*)

[*w*, *iw*] = **max** (*x*)

- For a vector argument, return the maximum value. For a matrix argument, return the maximum value from each column, as a row vector, or over the dimension
*dim*if defined. For two matrices (or a matrix and scalar), return the pair-wise maximum. Thus,

max (max (x))

- returns the largest element of
*x*, and

max (2:5, pi) 3.1416 3.1416 4.0000 5.0000

- compares each element of the range
`2:5`with`pi`, and returns a row vector of the maximum values.

- For complex arguments, the magnitude of the elements are used for comparison.

- If called with one input and two output arguments, max also returns the first index of the maximum value(s). Thus,

[x, ix] = max ([1, 3, 5, 2, 5]) x = 5 ix = 3

## min

**min** (*x*, *y*, *dim*)

[*w*, *iw*] = **min** (*x*)

- For a vector argument, return the minimum value. For a matrix argument, return the minimum value from each column, as a row vector, or over the dimension
*dim*if defined. For two matrices (or a matrix and scalar), return the pair-wise minimum. Thus,

min (min (x))

- returns the smallest element of
*x*, and

min (2:5, pi) 2.0000 3.0000 3.1416 3.1416

- compares each element of the range
`2:5`with`pi`, and returns a row vector of the minimum values.

- For complex arguments, the magnitude of the elements are used for comparison.

- If called with one input and two output arguments, min also returns the first index of the minimum value(s). Thus,

[x, ix] = min ([1, 3, 0, 2, 5]) x = 0 ix = 3

## hist

**hist** (*y*, *x*)

- Produce histogram counts or plots.

- With one vector input argument, plot a histogram of the values with 10 bins. The range of the histogram bins is determined by the range of the data.

- Given a second scalar argument, use that as the number of bins.

- Given a second vector argument, use that as the centers of the bins, with the width of the bins determined from the adjacent values in the vector.

- Extreme values are lumped in the first and last bins.

- With two output arguments, produce the values
*nn*and*xx*such that bar (*xx*,*nn*) will plot the histogram.

## bar

**bar** (*x*, *y*)

- Given two vectors of x-y data, bar produces a bar graph.

- If only one argument is given, it is taken as a vector of y-values and the x coordinates are taken to be the indices of the elements.

- If two output arguments are specified, the data are generated but not plotted. For example,

bar (x, y);

- and

[xb, yb] = bar (x, y); plot (xb, yb);

- are equivalent.

## plot

**plot** (*args*)

- This function produces two-dimensional plots. Many different combinations of arguments are possible. The simplest form is

plot (y)

- where the argument is taken as the set of
*y*coordinates and the*x*coordinates are taken to be the indices of the elements, starting with 1.

- If more than one argument is given, they are interpreted as

plot (x, y, fmt ...)

- where
*y*and*fmt*are optional, and any number of argument sets may appear. The*x*and*y*values are interpreted as follows:

- If a single data argument is supplied, it is taken as the set of
*y*coordinates and the*x*coordinates are taken to be the indices of the elements, starting with 1.

- If a single data argument is supplied, it is taken as the set of

- If the first argument is a vector and the second is a matrix, then the vector is plotted versus the columns (or rows) of the matrix. (using whichever combination matches, with columns tried first.)

- If the first argument is a matrix and the second is a vector, the the columns (or rows) of the matrix are plotted versus the vector. (using whichever combination matches, with columns tried first.)

- If both arguments are vectors, the elements of
*y*are plotted versus the elements of*x*.

- If both arguments are vectors, the elements of

- If both arguments are matrices, the columns of
*y*are plotted versus the columns of*x*. In this case, both matrices must have the same number of rows and columns and no attempt is made to transpose the arguments to make the number of rows match.

- If both arguments are matrices, the columns of

- If both arguments are scalars, a single point is plotted.

- The fmt argument, if present is interpreted as follows. If fmt is missing, the default gnuplot line style is assumed.

`-'

- Set lines plot style (default).

`.'

- Set dots plot style.

`@'

- Set points plot style.

`-@'

- Set linespoints plot style.

`^'

- Set impulses plot style.

`L'

- Set steps plot style.

`#'

- Set boxes plot style.

`~'

- Set errorbars plot style.

`#~'

- Set boxerrorbars plot style.

`n'

- Interpreted as the plot color if
*n*is an integer in the range 1 to 6.

- Interpreted as the plot color if

`nm'

- If
*nm*is a two digit integer and*m*is an integer in the range 1 to 6,*m*is interpreted as the point style. This is only valid in combination with the @ or -@ specifiers.

- If

`c'

- If c is one of
`"r"`,`"g"`,`"b"`,`"m"`,`"c"`, or`"w"`, it is interpreted as the plot color (red, green, blue, magenta, cyan, or white).

- If c is one of

`+' `*' `o' `x'

- Used in combination with the points or linespoints styles, set the point style.

- The color line styles have the following meanings on terminals that support color.

Number Gnuplot colors (lines)points style 1 red * 2 green + 3 blue o 4 magenta x 5 cyan house 6 brown there exists

- Here are some plot examples:

plot (x, y, "@12", x, y2, x, y3, "4", x, y4, "+")

- This command will plot
*y*with points of type 2 (displayed as``+'`) and color 1 (red),*y2*with lines,*y3*with lines of color 4 (magenta) and*y4*with points displayed as``+'`.

plot (b, "*")

- This command will plot the data in the variable
*b*will be plotted with points displayed as``*'`.