Octave can plot a function from a function handle or string defining the
function without the user needing to explicitly create the data to be
plotted. The function `fplot`

also generates two-dimensional plots
with linear axes using a function name and limits for the range of the
x-coordinate instead of the x and y data. For example,

fplot (@sin, [-10, 10], 201);

produces a plot that is equivalent to the one above, but also includes a legend displaying the name of the plotted function.

- :
**fplot**`(`

¶`fcn`) - :
**fplot**`(`

¶`fcn`,`limits`) - :
**fplot**`(…,`

¶`tol`) - :
**fplot**`(…,`

¶`n`) - :
**fplot**`(…,`

¶`fmt`) - :
**fplot**`(…,`

¶`property`,`value`, …) - :
**fplot**`(`

¶`hax`, …) - :
`[`

`x`,`y`] =**fplot**`(…)`

¶ Plot a function

`fcn`within the range defined by`limits`.`fcn`is a function handle, inline function, or string containing the name of the function to evaluate.The limits of the plot are of the form

`[`

or`xlo`,`xhi`]`[`

. If no limits are specified the default is`xlo`,`xhi`,`ylo`,`yhi`]`[-5, 5]`

.The next three arguments are all optional and any number of them may be given in any order.

`tol`is the relative tolerance to use for the plot and defaults to 2e-3 (.2%).`n`is the minimum number of points to use. When`n`is specified, the maximum stepsize will be`(`

. More than`xhi`-`xlo`) /`n``n`points may still be used in order to meet the relative tolerance requirement.The

`fmt`argument specifies the linestyle to be used by the plot command.Multiple property-value pairs may also be specified, but they must appear in pairs. These arguments are applied to the line objects drawn by

`plot`

.The full list of line properties is documented at Line Properties.

If the first argument

`hax`is an axes handle, then plot into this axes, rather than the current axes returned by`gca`

.With no output arguments, the results are immediately plotted. With two output arguments, the 2-D plot data is returned. The data can subsequently be plotted manually with

`plot (`

.`x`,`y`)Example:

fplot (@cos, [0, 2*pi]) fplot ("[cos(x), sin(x)]", [0, 2*pi])

Programming Notes:

`fplot`

works best with continuous functions. Functions with discontinuities are unlikely to plot well. This restriction may be removed in the future.`fplot`

performance is better when the function accepts and returns a vector argument. Consider this when writing user-defined functions and use element-by-element operators such as`.*`

,`./`

, etc.

Other functions that can create two-dimensional plots directly from a
function include `ezplot`

, `ezcontour`

, `ezcontourf`

and
`ezpolar`

.

- :
**ezplot**`(`

¶`f`) - :
**ezplot**`(`

¶`f2v`) - :
**ezplot**`(`

¶`fx`,`fy`) - :
**ezplot**`(…,`

¶`dom`) - :
**ezplot**`(…,`

¶`n`) - :
**ezplot**`(`

¶`hax`, …) - :
`h`=**ezplot**`(…)`

¶ -
Plot the 2-D curve defined by the function

`f`.The function

`f`may be a string, inline function, or function handle and can have either one or two variables. If`f`has one variable, then the function is plotted over the domain`-2*pi <`

with 500 points.`x`< 2*piIf

`f2v`is a function of two variables then the implicit function

is calculated over the meshed domain`f`(`x`,`y`) = 0`-2*pi <=`

with 60 points in each dimension.`x`|`y`<= 2*piFor example:

ezplot (@(

`x`,`y`)`x`.^2 -`y`.^2 - 1)If two functions are passed as inputs then the parametric function

`x`=`fx`(`t`)`y`=`fy`(`t`)is plotted over the domain

`-2*pi <=`

with 500 points.`t`<= 2*piIf

`dom`is a two element vector, it represents the minimum and maximum values of both`x`and`y`, or`t`for a parametric plot. If`dom`is a four element vector, then the minimum and maximum values are`[xmin xmax ymin ymax]`

.`n`is a scalar defining the number of points to use in plotting the function.If the first argument

`hax`is an axes handle, then plot into this axes, rather than the current axes returned by`gca`

.The optional return value

`h`is a vector of graphics handles to the created line objects.**See also:**plot, ezplot3, ezpolar, ezcontour, ezcontourf, ezmesh, ezmeshc, ezsurf, ezsurfc.

- :
**ezcontour**`(`

¶`f`) - :
**ezcontour**`(…,`

¶`dom`) - :
**ezcontour**`(…,`

¶`n`) - :
**ezcontour**`(`

¶`hax`, …) - :
`h`=**ezcontour**`(…)`

¶ -
Plot the contour lines of a function.

`f`is a string, inline function, or function handle with two arguments defining the function. By default the plot is over the meshed domain`-2*pi <=`

with 60 points in each dimension.`x`|`y`<= 2*piIf

`dom`is a two element vector, it represents the minimum and maximum values of both`x`and`y`. If`dom`is a four element vector, then the minimum and maximum values are`[xmin xmax ymin ymax]`

.`n`is a scalar defining the number of points to use in each dimension.If the first argument

`hax`is an axes handle, then plot into this axes, rather than the current axes returned by`gca`

.The optional return value

`h`is a graphics handle to the created plot.Example:

f = @(x,y) sqrt (abs (x .* y)) ./ (1 + x.^2 + y.^2); ezcontour (f, [-3, 3]);

**See also:**contour, ezcontourf, ezplot, ezmeshc, ezsurfc.

- :
**ezcontourf**`(`

¶`f`) - :
**ezcontourf**`(…,`

¶`dom`) - :
**ezcontourf**`(…,`

¶`n`) - :
**ezcontourf**`(`

¶`hax`, …) - :
`h`=**ezcontourf**`(…)`

¶ -
Plot the filled contour lines of a function.

`f`is a string, inline function, or function handle with two arguments defining the function. By default the plot is over the meshed domain`-2*pi <=`

with 60 points in each dimension.`x`|`y`<= 2*piIf

`dom`is a two element vector, it represents the minimum and maximum values of both`x`and`y`. If`dom`is a four element vector, then the minimum and maximum values are`[xmin xmax ymin ymax]`

.`n`is a scalar defining the number of points to use in each dimension.`hax`is an axes handle, then plot into this axes, rather than the current axes returned by`gca`

.The optional return value

`h`is a graphics handle to the created plot.Example:

f = @(x,y) sqrt (abs (x .* y)) ./ (1 + x.^2 + y.^2); ezcontourf (f, [-3, 3]);

- :
**ezpolar**`(`

¶`f`) - :
**ezpolar**`(…,`

¶`dom`) - :
**ezpolar**`(…,`

¶`n`) - :
**ezpolar**`(`

¶`hax`, …) - :
`h`=**ezpolar**`(…)`

¶ -
Plot a 2-D function in polar coordinates.

The function

`f`is a string, inline function, or function handle with a single argument. The expected form of the function is

. By default the plot is over the domain`rho`=`f`(`theta`)`0 <=`

with 500 points.`theta`<= 2*piIf

`dom`is a two element vector, it represents the minimum and maximum values of`theta`.`n`is a scalar defining the number of points to use in plotting the function.`hax`is an axes handle, then plot into this axes, rather than the current axes returned by`gca`

.The optional return value

`h`is a graphics handle to the created plot.Example:

ezpolar (@(t) sin (5/4 * t), [0, 8*pi]);