very narrow imagesc subplots

[Drew Davidson]

In the following simple example code, the (sub)plots are coming out much 
too narrow in width (x-direction) by default; they are unreadable.  The 
default amount of whitespace is truly excessive. When I attempt to widen 
the 3rd subplot by a factor beta, I get unexpected results.  I am 
expecting the 3rd subplot to remain in position and to simply widen in 
the x-direction, but instead the subplot seems to move around and stay 
narrow.  This suggests the origin of the subplot is far away, but why 
would the subplot stay narrow?  If someone would please run this brief 
example code, play with the value of beta, and explain what is 
happening, I would be grateful.  What is a simple way to make these 
subplots wider?

This code is based on the first web link in the initial comments.  I did 
try "tightfig.m" and "tight_subplot.m" from the Matlab File Exchange on 
some different code than below (but still imagesc in subplots), and 
experienced similar frustration.

Using octave 3.8.1 in Ubuntu 14.04.




%http://stackoverflow.com/questions/16064451/reposition-colorbar-or-subplots
%https://www.gnu.org/software/octave/doc/interpreter/Axes-Properties.html
%http://blogs.mathworks.com/pick/2012/12/21/figure-margins-subplot-spacings-and-more/

clear;
close all;

figure(10)
ax(1) = subplot(1,3,1);imagesc(rand(100,1),[0 1]);
ax(2) = subplot(1,3,2);imagesc(rand(100,1),[0 1]);
ax(3) = subplot(1,3,3);imagesc(rand(100,1),[0 1]);

figure(20)
ax2(1) = subplot(1,3,1);imagesc(rand(100,1),[0 1]);
ax2(2) = subplot(1,3,2);imagesc(rand(100,1),[0 1]);
ax2(3) = subplot(1,3,3);imagesc(rand(100,1),[0 1]);

% Get positions of all the subplot
posa = get(ax,'position');
posa2 = get(ax2,'position');
%h    = colorbar;

%attempt to make the 3rd subplot wider in figure 20.  why does this fail???
m=3;
beta=3.0;
posa2{3}(m)=posa2{3}(m)*beta;

set(ax2(3),'position',posa2{3})