Tips on combining while loop

Hello forum,

I need some tips on combining 3 same while loop with different input. I separated the input, but actually the input can be united into one.

V = -12

V1 = 12

V = 0

can be combined into V=[-12 0 12]

But unfortunately I do not know how.

Thank you.

%Pohlhausen/thwaites polynomial

clear;clc;close;


i = 1; 
j = 1;
k = 1;
V = -12; %Upper case lambda 
V1 = 12; %Upper case lambda 
V2 = 0; %Upper case lambda 
ys = 0; %y/delta - normalized y axis. delta is BL thickness (minimum)
ys1 = 0; %y/delta - normalized y axis. delta is BL thickness (minimum)
ys2 = 0; %y/delta - normalized y axis. delta is BL thickness (minimum)
 
%upper case lambda -12
while ys <=1 ; %y/delta - normalized y axis. delta is BL thickness (maximum)
    
    x(i) = ys; %range of normalize y
    f (i)=(2*ys - 2*ys^3 + ys^4) + ((V/6*ys)*(1-ys)^3); %u/U_infinity - pohlhausen velocity distribution                 
    
    
    ys = ys + 0.01; %step of normalize y
    i = i+1;   %array step
  
end

%upper case lambda -12
while ys1 <=1 ; %y/delta - normalized y axis. delta is BL thickness (maximum)
    
    xa(j) = ys1; %range of normalize y
    g (j)=(2*ys1 - 2*ys1^3 + ys1^4) + ((V1/6*ys1)*(1-ys1)^3); %u/U_infinity - pohlhausen velocity distribution                 
    
    
    ys1 = ys1 + 0.01; %step of normalize y
    j = j+1;   %array step
  
end

%upper case lambda 0
while ys2 <=1 ; %y/delta - normalized y axis. delta is BL thickness (maximum)
    
    xb(k) = ys2; %range of normalize y
    h (k)=(2*ys2 - 2*ys2^3 + ys2^4) + ((V2/6*ys2)*(1-ys2)^3); %u/U_infinity - pohlhausen velocity distribution                 
    
    
    ys2 = ys2 + 0.01; %step of normalize y
    k = k+1;   %array step
  
end




figure(1)
plot(x,f,'r-',xa,g,'b-',xb,h,'c-','LineWidth', 2)
hold on
grid on
title('Pohlhausen Velocity distribution')
ylabel('u/U_\infty', 'FontSize', 20)
xlabel('y* = y/\delta','FontSize', 20)
legend('\Lambda = 12','\Lambda = -12','\Lambda = 0','location','southeast')
ylim([0 1.1])

Answer 1

[Rik]

You were creating a function, why not make that explicit?

%Pohlhausen/thwaites polynomial

%clear;clc;close;
% ^^^^^^ you don't need this

i = 1; 
j = 1;
k = 1;
V = -12; %Upper case lambda 
V1 = 12; %Upper case lambda 
V2 = 0; %Upper case lambda 
ys = 0; %y/delta - normalized y axis. delta is BL thickness (minimum)
ys1 = 0; %y/delta - normalized y axis. delta is BL thickness (minimum)
ys2 = 0; %y/delta - normalized y axis. delta is BL thickness (minimum)
 
%upper case lambda -12
[x,f]=myFun(i,V,ys);

%upper case lambda -12
%                  ^ is that correct?
[xa,g]=myFun(j,V1,ys1);

%upper case lambda 0
[xb,h]=myFun(k,V2,ys2);


figure(1),clf(1)
%        ^^^^^^^
%during debugging you can add this to make sure your figure is clean
plot(x,f,'r-',xa,g,'b-',xb,h,'c-','LineWidth', 2)
%hold on
% you aren't plotting anything else, so hold on is not required
grid on
title('Pohlhausen Velocity distribution')
ylabel('u/U_\infty', 'FontSize', 20)
xlabel('y* = y/\delta','FontSize', 20)
legend('\Lambda = 12','\Lambda = -12','\Lambda = 0','location','southeast')
ylim([0 1.1])

function [x,f]=myFun(i,V,ys)
%Write documentation explaining this function here
%
%write syntax examples as well

%Do input checking and make sure any errors that can occur will trigger an
%error here, so the user can understand what they need to change.
%After this input validation step, no error is allowed to occur.

x=zeros(1,ceil((ys-1)/0.01);%pre-allocate array
f=zeros(size(x));%pre-allocate array
while ys <=1 ; %y/delta - normalized y axis. delta is BL thickness (maximum)
    x(i) = ys; %range of normalize y
    f(i)=(2*ys - 2*ys^3 + ys^4) + ...
        ((V/6*ys)*(1-ys)^3); %u/U_infinity - pohlhausen velocity distribution                 
    ys = ys + 0.01; %step of normalize y
    i = i+1;   %array step
end
if numel(x)>i
    %remove padding
    x(i+1:end)=[];
    f(i+1:end)=[];
end
end