Upon running the following script the image of the matrix appears together with the colorbar, but the colorbar is upside down, i.e. according to the colorbar zero is yellow and 1 is dark purple, but in the matrix its the otherr way around.
The script:
P=[1, 0, 0, 0, 0;
0.6, 0, 0.4, 0, 0;
0, 0.6, 0, 0.4, 0;
0, 0, 0.6, 0, 0.4;
0,0, 0, 0, 1]
Q=PPPPP
imagesc(Q)
colorbar