ezsurf (MATLAB Functions)

Easy to use 3-D colored surface plotter

Syntax

ezsurf(fun)
ezsurf(fun,domain)
ezsurf(funx,funy,funz)
ezsurf(funx,funy,funz,[smin,smax,tmin,tmax]) or 
ezsurf(funx,funy,funz,[min,max])
ezsurf(...,n)
ezsurf(...,'circ')
ezsurf(axes_handle,...)
h = ezsurf(...)

Description

ezsurf(fun) creates a graph of fun(x,y) using the surf function. fun is plotted over the default domain: -2 < x < 2, -2 < y < 2.

fun can be a function handle for an M-file function or an anonymous function (see Function Handles and Anonymous Functions) or a string (see the Remarks section).

ezsurf(fun,domain) plots fun over the specified domain. domain can be either a 4-by-1 vector [xmin, xmax, ymin, ymax] or a 2-by-1 vector [min, max] (where min < x < max, min < y < max).

ezsurf(funx,funy,funz) plots the parametric surface funx(s,t), funy(s,t), and funz(s,t) over the square: -2 < s < 2, -2 < t < 2.

ezsurf(funx,funy,funz,[smin,smax,tmin,tmax]) or ezsurf(funx,funy,funz,[min,max]) plots the parametric surface using the specified domain.

ezsurf(...,n) plots fun over the default domain using an n-by-n grid. The default value for n is 60.

ezsurf(...,'circ') plots fun over a disk centered on the domain.

ezsurf(axes_handle,...) plots into the axes with handle axes_handle instead of the current axes (gca).

h = ezsurf(...) returns the handle to a surface object in h.

Remarks

Passing the Function as a String

Array multiplication, division, and exponentiation are always implied in the expression you pass to ezmesh. For example, the MATLAB syntax for a surface plot of the expression

```
sqrt(x.^2 + y.^2);
```

is written as

```
ezsurf('sqrt(x^2 + y^2)')
```

That is, x^2 is interpreted as x.^2 in the string you pass to ezsurf.

If the function to be plotted is a function of the variables u and v (rather than x and y), then the domain endpoints umin, umax, vmin, and vmax are sorted alphabetically. Thus, ezsurf('u^2 - v^3',[0,1],[3,6]) plots u² - v³ over 0 < u < 1, 3 < v < 6.

Passing a Function Handle

Function handle arguments must point to functions that use MATLAB syntax. For example, the following statements define an anonymous function and pass the function handle fh to ezsurf.

fh = @(x,y) sqrt(x.^2 + y.^2);
ezsurf(fh)

Note that when using function handles, you must use the array power, array multiplication, and array division operators (.^, .*, ./) since ezsurf does not alter the syntax, as in the case with string inputs.

Passing Additional Arguments

If your function has additional parameters, for example k in myfun:

function z = myfun(x,y,k1,k2,k3)
z = x.*(y.^k1)./(x.^k2 + y.^k3);

then you can use an anonymous function to specify that parameter:

```
ezsurf(@(x,y)myfun(x,y,2,2,4))
```

Examples

ezsurf does not graph points where the mathematical function is not defined (these data points are set to NaNs, which MATLAB does not plot). This example illustrates this filtering of singularities/discontinuous points by graphing the function

over the default domain -2 < x < 2, -2 < y < 2:

```
ezsurf('real(atan(x+i*y))')
```

Using surf to plot the same data produces a graph without filtering of discontinuities (as well as requiring more steps):

[x,y] = meshgrid(linspace(-2*pi,2*pi,60));
z = real(atan(x+i.*y));
surf(x,y,z)

Note also that ezsurf creates graphs that have axis labels, a title, and extend to the axis limits.

See Also

ezmesh, ezsurfc, function_handle, surf

Function Plots for related functions

ezpolar ezsurfc