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Octave can plot a function from a function handle inline function 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.
Plot a function fn within defined limits.
fn is a function handle, inline function, or string
containing the name of the function to evaluate.
The limits of the plot are given by limits of the form
[xlo, xhi]
or [xlo, xhi,
ylo, yhi]
. tol is the default tolerance to use for the
plot, and if tol is an integer it is assumed that it defines the
number points to use in the plot. The fmt argument is passed
to the plot command.
fplot ("cos", [0, 2*pi]) fplot ("[cos(x), sin(x)]", [0, 2*pi])
See also: plot.
Other functions that can create two-dimensional plots directly from a
function include ezplot
, ezcontour
, ezcontourf
and
ezpolar
.
Plot the curve defined by f in two dimensions. 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 < x < 2*pi
with 500 points.
If f has two variables then f(x,y) = 0
is calculated over the meshed domain -2*pi < x | y
< 2*pi
with 60 by 60 in the mesh. For example:
ezplot (@(x, y) x.^2 - y.^2 - 1)
If two functions are passed as strings, inline functions or function handles, then the parametric function
x = fx (t) y = fy (t)
is plotted over the domain -2*pi < t < 2*pi
with 500
points.
If dom is a two element vector, it represents the minimum and maximum value of x, y and t. If it is a four element vector, then the minimum and maximum values of x and t are determined by the first two elements and the minimum and maximum of y by the second pair of elements.
n is a scalar defining the number of points to use in plotting the function.
The optional return value h is a graphics handle to the created plot.
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 domain -2*pi < x < 2*pi
and -2*pi <
y < 2*pi
with 60 points in each dimension.
If dom is a two element vector, it represents the minimum and maximum value of both x and y. If dom is a four element vector, then the minimum and maximum value of x and y are specify separately.
n is a scalar defining the number of points to use in each dimension.
The optional return value h is a graphics handle to the created plot.
f = @(x,y) sqrt (abs (x .* y)) ./ (1 + x.^2 + y.^2); ezcontour (f, [-3, 3]);
See also: ezplot, ezcontourf, ezsurfc, ezmeshc.
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 domain -2*pi < x < 2*pi
and
-2*pi < y < 2*pi
with 60 points in each dimension.
If dom is a two element vector, it represents the minimum and maximum value of both x and y. If dom is a four element vector, then the minimum and maximum value of x and y are specify separately.
n is a scalar defining the number of points to use in each dimension.
The optional return value h is a graphics handle to the created plot.
f = @(x,y) sqrt (abs (x .* y)) ./ (1 + x.^2 + y.^2); ezcontourf (f, [-3, 3]);
Plot a function in polar coordinates. The function f is either
a string, inline function or function handle with one arguments defining
the function. By default the plot is over the domain 0 < x <
2*pi
with 60 points.
If dom is a two element vector, it represents the minimum and maximum value of both t. n is a scalar defining the number of points to use.
The optional return value h is a graphics handle to the created plot.
ezpolar (@(t) 1 + sin (t));
Next: Two-dimensional Geometric Shapes, Previous: Axis Configuration, Up: Two-Dimensional Plots [Contents][Index]