function q=mmhole(x,y,z,xlim,ylim)%MMHOLE Create Hole in 3D Graphics Data% Z=MMHOLE(X,Y,Z,Xlim,Ylim) sets the data in Z to NaN% corresponding to the limits in Xlim=[Xmin Xmax] and% Ylim=[Ymin Ymax]. If Xlim or Ylim are empty they are% assumed to be [-inf inf].% X and Y can be plaid matrices, e.g., created by MESHGRID% or they can be vectors defining the x and y axes.%% Z=MMHOLE(Z,Clim,Rlim) creates the NaN hole based on the % column index limits in Clim and the row index limits in Rlim%% Resulting data can be plotted using mesh or surf:% MESH(X,Y,Z) or SURF(X,Y,Z)% This function automates the procedure described on% page 249 of "Mastering MATLAB".% D.C. Hanselman, University of Maine, Orono ME,  04469% 9/26/95% Copyright (c) 1996 by Prentice-Hall, Inc.if nargin==3	% MMHOLE(Z,Clim,Rlim)	ylim=z;	xlim=y;	z=x;	% rearrange variables as required	x=1:size(z,2);	y=1:size(z,1);endif length(xlim)<2, xlim=[-inf inf];else xlim=xlim(1:2);endif length(ylim)<2, ylim=[-inf inf];else ylim=ylim(1:2);endsx=size(x);sy=size(y);sz=size(z);if all(sx==sz), x=x(1,:); end		% get x-axis vectorif all(sy==sz), y=y(:,1); end		% get y-axis vectori=find(y>=ylim(1) & y<=ylim(2));	% y indices of holej=find(x>=xlim(1) & x<=xlim(2));	% x indices of holeq=z;q(i,j)=nan*q(i,j);