# How to switch to this graph? Mathematical question

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Elia Paini on 3 Nov 2021
Commented: Star Strider on 6 Nov 2021
Hi, I have a bit complicated question about a way to obtain a graph from a set of data.
I have a code that return a solution of three variables, related to solving a system of several equations.
For example, Matlab output is like the following:
a = [1 0.2 0.2];
b = [0 0.4 0.4];
c = [0 0.4 0.4]; which are plotted on distance x = [0 0.5 1];
a, b, c represent three volume fractions, with the constraint that sum over a column is 1 (on the left of the figure).
However, for an easier understanding, I need a graphic representation showing not the absolute values of those fractions, but their distribution (on the right).
I know it's likely a "mathematical question" than "Matlab question", but I don't know how to proceed.
I need an appliable strategy on any solution, not this one in particular.
Thanks for your help!! Star Strider on 3 Nov 2021
Try this —
x = [0 0.5 1];
a = [1 0.2 0.2];
b = [0 0.4 0.4];
c = [0 0.4 0.4];
figure
patch([x flip(x)], [c zeros(size(c))], 'g', 'FaceAlpha',0.75)
hold on
patch([x flip(x)], [b ones(size(a))], 'r', 'FaceAlpha',0.75)
patch([x flip(x)], [b flip(a+c)], 'b', 'FaceAlpha',0.75)
hold off
text([1 1 1]*0.8, [0.2 0.5 0.8], compose('%c',['c','a','b']), 'FontWeight','bold') .
Star Strider on 6 Nov 2021
As always, my pleasure!
.

### More Answers (1)

Alan Stevens on 3 Nov 2021
Try:
plot(x,c,x,1-b)
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Elia Paini on 3 Nov 2021
Edited: Elia Paini on 3 Nov 2021
This is correct, there's only one problem.
This can be coupled only to this easy example. Actually, solution can be very complex, also with 50 points for every variable. The example I considered is very easy, with only three points and regular lines.
My question is not about that problem, I asked for a single code which can be applied to every case.
I hope you understand me.