How can I plot phase diagrams in MATLAB?

Is it possible to plot phase diagrams as the attached ones using MATLAB?

Thanks!

[DGM]

Do you have any data to describe the boundaries?

If you do, you might start with fill() or patch().

[Waseem AL Aqqad]

Thanks DGM.

Answer 1

[Voss]

Here's how you might produce something similar to 2.jpg:

p = [0.13 0.26 0.42 0.52]; % adjust these points along the curve to your liking
g = [1    0.8  0.4  0   ];

patch([0 p 0],g([1 1:end end]),[246 173 203]/255);
patch(p([1:end end]),g([1:end 1]),[255 249 173]/255);
patch([p([end end]) 1 1],g([1 end end 1]),[204 231 212]/255);
line(p,g,'Color',[0 0 0],'LineWidth',1.5);

text(0.67,0.44,'Regime I','Color',[93 48 107]/255,'FontSize',14);
text(0.33,0.82,'Regime II','Color',[93 48 107]/255,'FontSize',14);
text(0.07,0.42,'Regime III','Color',[93 48 107]/255,'FontSize',14);
text(0.9,0.9,'(c)','FontSize',16);

xlabel('p');
ylabel('\gamma');
set(gca(),'FontSize',12,'FontWeight','bold','XTick',0:0.1:1,'YTick',0:0.2:1);

[Waseem AL Aqqad]

Thank you so much. I tried to define the boundaries of the regions for the attached file but I couldn't. Here what I did:

a1 = [0.45 0.45 0.5 0.55 0.55 0.6 0.65 0.65 0.7 0.7 0.75 0.75 0.8 0.85 0.9 0.9 0.95]; 
p1 = [0.95 0.9 0.85 0.8 0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.3 0.25 0.25];

a2 = [0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95];
p2 = [0.05 0.95 0.95 0.95 0.95 0.95 0.95 0.9 0.85 0.8 0.7 0.65 0.55 0.45 0.35 0.3 0.25 0.25 0.25];
% a3 = [0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95];
% p3 = [0.95 0.95 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05];
a3 = [.05 0.05];
p3 = [0.95 0.05];

patch(a3,p3,[246 173 203]/255);
patch(a2,p2,[255 249 173]/255);
patch(a1,p1,[204 231 212]/255);


text(0.8,0.7,'Regime I','Color',[93 48 107]/255,'FontSize',14);
text(0.4,0.42,'Regime II','Color',[93 48 107]/255,'FontSize',14);
text(0.02,0.42,'Regime III','Color',[93 48 107]/255,'FontSize',14);
text(0.9,0.9,'(c)','FontSize',16);

xlabel('\alpha');
ylabel('P');
set(gca(),'FontSize',12,'FontWeight','bold','XTick',0:0.2:1,'YTick',0:0.2:1);

Your help is greatly appreciated.

[Voss]

You have the right idea, which is to write down the x,y coordinates of the points along the edges of a patch in order. What you are missing is that you have to essentially go all the way around the perimeter of the patch. That is, you must include the points where the patch goes to the x- and/or y-axis or otherwise to the edge of the plot region. See my comments in the code below, explaining in slightly more detail for this particular case.

% I added one point here at (0.95, 0.95) to get the patch to extend to the
% upper-right corner of the plot
a1 = [0.45 0.45 0.5 0.55 0.55 0.6 0.65 0.65 0.7 0.7 0.75 0.75 0.8 0.85 0.9 0.9 0.95 0.95];
p1 = [0.95 0.9 0.85 0.8 0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.3 0.25 0.25 0.95];

% then use those same points - except for the corner one I added -
% for the yellow patch, since all those points are common to
% the green patch as well, along the boundary between yellow and green
a2 = [0.05 a1(1:end-1) 0.95 0.05];
p2 = [0.95 p1(1:end-1) 0.05 0.05];

% red patch makes an L-shape
a3 = [0 0    0.05 0.05 0.95 0.95];
p3 = [0 0.95 0.95 0.05 0.05 0   ];

% a2 = [0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95];
% p2 = [0.05 0.95 0.95 0.95 0.95 0.95 0.95 0.9 0.85 0.8 0.7 0.65 0.55 0.45 0.35 0.3 0.25 0.25 0.25];
% % a3 = [0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95];
% % p3 = [0.95 0.95 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05];
% a3 = [.05 0.05];
% p3 = [0.95 0.05];

patch(a3,p3,[246 173 203]/255);
patch(a2,p2,[255 249 173]/255);
patch(a1,p1,[204 231 212]/255);

text(0.8,0.7,'Regime I','Color',[93 48 107]/255,'FontSize',14);
text(0.4,0.42,'Regime II','Color',[93 48 107]/255,'FontSize',14);
text(0.02,0.42,'Regime III','Color',[93 48 107]/255,'FontSize',14);
text(0.9,0.9,'(c)','FontSize',16);

xlabel('\alpha');
ylabel('P');
set(gca(),'FontSize',12,'FontWeight','bold','XTick',0:0.2:1,'YTick',0:0.2:1);

[Waseem AL Aqqad]

Now I see what I was missing. Thank you very much for the nice explanation.