MATLAB Function Reference    

Plot a function between specified limits



fplot plots a function between specified limits. The function must be of the form y = f(x), where x is a vector whose range specifies the limits, and y is a vector the same size as x and contains the function's value at the points in x (see the first example). If the function returns more than one value for a given x, then y is a matrix whose columns contain each component of f(x) (see the second example).

fplot('function',limits) plots 'function' between the limits specified by limits. limits is a vector specifying the x-axis limits ([xmin xmax]), or the x- and y-axis limits, ([xmin xmax ymin ymax]).

'function' must be the name of an M-file function or a string with variable x that may be passed to eval, such as 'sin(x)', 'diric(x,10)' or '[sin(x),cos(x)]'.

The function f(x) must return a row vector for each element of vector x. For example, if f(x) returns [f1(x),f2(x),f3(x)] then for input [x1;x2] the function should return the matrix

fplot('function',limits,LineSpec) plots 'function' using the line specification LineSpec.

fplot('function',limits,tol) plots 'function' using the relative error tolerance tol (The default is 2e-3, i.e., 0.2 percent accuracy).

fplot('function',limits,tol,LineSpec) plots 'function' using the relative error tolerance tol and a line specification that determines line type, marker symbol, and color.

fplot('function',limits,n) with n >= 1 plots the function with a minimum of n+1 points. The default n is 1. The maximum step size is restricted to be (1/n)*(xmax-xmin).

fplot(fun,lims,...) accepts combinations of the optional arguments tol, n, and LineSpec, in any order.

[X,Y] = fplot('function',limits,...) returns the abscissas and ordinates for 'function' in X and Y. No plot is drawn on the screen, however you can plot the function using plot(X,Y).

[...] = plot('function',limits,tol,n,LineSpec,P1,P2,...) enables you to pass parameters P1, P2, etc. directly to the function 'function':

To use default values for tol, n, or LineSpec, you can pass in the empty matrix ([]).


fplot uses adaptive step control to produce a representative graph, concentrating its evaluation in regions where the function's rate of change is the greatest.


Plot the hyperbolic tangent function from -2 to 2:

Create an M-file, myfun, that returns a two column matrix:

Plot the function with the statement:

Addition Examples

See Also

eval, ezplot, feval, LineSpec, plot

Function Plots for related functions

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