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The functions sombrero
and peaks
provide a way to check
that plotting is working. Typing either sombrero
or peaks
at the Octave prompt should display a three-dimensional plot.
Plot the familiar 3-D sombrero function.
The function plotted is
z = sin (sqrt (x^2 + y^2)) / (sqrt (x^2 + y^2))
Called without a return argument, sombrero
plots the surface of the
above function over the meshgrid [-8,8] using surf
.
If n is a scalar the plot is made with n grid lines. The default value for n is 41.
When called with output arguments, return the data for the function
evaluated over the meshgrid. This can subsequently be plotted with
surf (x, y, z)
.
Plot a function with lots of local maxima and minima.
The function has the form
f(x,y) = 3*(1-x)^2*exp(-x^2 - (y+1)^2) ... - 10*(x/5 - x^3 - y^5)*exp(-x^2-y^2) ... - 1/3*exp(-(x+1)^2 - y^2)
Called without a return argument, peaks
plots the surface of the
above function using surf
.
If n is a scalar, peaks
plots the value of the above
function on an n-by-n mesh over the range [-3,3]. The
default value for n is 49.
If n is a vector, then it represents the grid values over which to calculate the function. If x and y are specified then the function value is calculated over the specified grid of vertices.
When called with output arguments, return the data for the function
evaluated over the meshgrid. This can subsequently be plotted with
surf (x, y, z)
.
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