Basics of MATLAB and Beyond

clfaxes(’pos’,[.2 .1 .7 .4])x = linspace(0,2);plt(x,humps(x))axis tightzeroaxesaxes(’pos’,[.2 .5 .7 .4])plt(x,cumsum(humps(x)))set(gca,’xticklabel’,’’)axis tight32.3 SubplotsMultivariate data can be displayed by plotting arrays of subplots. Forexample, a column of x–y plots can represent y plotted as a function ofx and z. A sequence of such columns can represent another variable,so that you can see y plotted as a function of x, z, and t. matlab’ssubplot command is an easy way of generating arrays of plots, but youhave no control over the precise positioning; the gap between the plots,for example, is not controllable. The m-file pickbox (see companionsoftware) is designed for such cases. You give pickbox the number ofrows and columns you want in your array of plots, and pick out thenumber of the plot you want (in the same way as for subplot). You canalso specify the amount of x and y space between the plots as well as theamount of white space around the entire plot array. This space can beused for row and column labels. In the following example we generatesamples of the functionB(x, y, t) =(1− e −(2x)2 −y 2 )/tover a three-dimensional grid of x, y, and t. We display the samples bydrawing repeated plots of B as a function of x and arraying them overa matrix of rows and columns indexed by y, and t, respectively: 15xv = -1:.1:1;yv = -1:.2:1;tv = 1:5;[x,y,t] = ndgrid(xv, yv, tv);B = (1 - exp(-(2*x).^2 - y.^2))./t;Nx = length(xv);Ny = length(yv);Nt = length(tv);clfcount = 0;top = max(max(max(B)));15 The code is given in the companion m-file plotbxyt.c○ 2000 by CRC Press LLC