hello, i need to plot a graph (n) number of times with an offset of a known number between each line on the graph, note all the lnes should be parallel on the same graph but repeated

clear,clc,clf
format short
Q=3.3;
%gamma=8.43 kN/m3 = 859.62076503 Kg/m3 (*1000/9.81)
rouh=859.62076503;
g=9.81;
Gamma=(rouh.*g);
Zs=0;
Ze=0;
L=1285000;
Ks=(0.000045); 
Er=(1.*10.^-8);
viscosity=(3.83.*10.^-3); 
% material grade X70
strength= 482000000;
%API 5L
D5L=[12.75*0.0254 14*0.0254 16*0.0254 18*0.0254 20*0.0254 22*0.0254 24*0.0254 26*0.0254 28*0.0254 30*0.0254 32*0.0254 34*0.0254 36*0.0254 38*0.0254 40*0.0254 42*0.0254 44*0.0254 46*0.0254 48*0.0254 52*0.0254 56*0.0254 60*0.0254 64*0.0254 68*0.0254 72*0.0254 76*0.0254 80*0.0254]
V5L=((4.*Q)./(pi.*D5L.^2));
V=V5L(V5L > 1 & V5L < 4.5)
Do=((4.*Q)./(pi.*V)).^(0.5)
Re=(V.*Do./viscosity)
Fo=0.01;
    for I=0:1:10^6;
        Fn=(1./(-4.*log10((Ks./(3.71.*Do))+((1.26)./(Re.*sqrt(Fo)))))).^2;
        E=abs((Fn-Fo)/Fn);
            if  E<=Er;
               Fn=Fn(end),display(E),break,
            end
            if E>Er;
                Fo=Fn;
            end
    end
    
Hloss=((Fn.*L.*Q.^2)./(12.*Do.^5))
Hpump=Hloss+Ze-Zs
        PRESSURE=rouh.*g.*Hpump.*10.^(-5)
        numberofpumps=ceil(PRESSURE./90)
        pressureperpump=(PRESSURE./numberofpumps)
        Distancebetweeneachpump=L./numberofpumps
        
        
   %calculating Hloss every 128500M
   n=numberofpumps
   LC=1:128500:1285000;
    for i=1:1:length(LC);
        HlossN=((Fn.*LC(i).*Q.^2)./(12.*Do.^5))
        TEL(i,:)=(Hpump-HlossN+Zs)
        HGL(i,:)=(TEL(i,:)-((V.^2)./(2.*g)))
        PE=Gamma.*(HGL-Ze)
        T=((PE(i).*Do)./(2.*strength))
    end
    
   n=numberofpumps
    for ii=1:1:length(Do)
        subplot(4,4,ii)
        plot(LC,TEL(:,ii))
        hold on
        plot(LC,HGL(:,ii))
        xlabel('LC')
        ylabel('HGL & TEL')
    end

....

please note that the the number of lines that should be available per graph is the (number of pumps)--line 37

and each line should be (distance between each pump)--line 39 away from the line before it.

it should look like that

Answer 1

[Cris LaPierre]

You don't want to use subplot. Look into the hold command.

[Cris LaPierre]

Actually, looking at the plot you shared, I don't think you want to use subplot or hold. I don't think you want to plot inside a loop at all. Use the loop to build up the X and Y vectors and then plot. Here's an example:

n = 4;
dx = 10;
y = 9;
X = [];
Y = [];

for loop = 1:n
nX = [0 10] + loop*dx;
X = [X nX];

Y = [Y y 0];
end

plot(X,Y)

[omar mahallawy]

actually, i do need the subplot becasue i need to draw the same graph 13 times but for different values, to choose an optimal input variable, not really our concern at the moment, moving on to the hold on command, it's there beacuse there are two lines per graph, you just need to zoom in quite a lot.

[Cris LaPierre]

Ok, fair enough. So now you would just need to adapt your code to the example I provided. I'd recommend picking just one of the 13 to work on first. Once you get it working for one subplot, it should be easy to get it to do it for all of them.

[omar mahallawy]

okay, i'm sorry but i don't understand what is nX?

[Cris LaPierre]

nX is a variable that holds the x points for the nth repetition of the plot. The first time it is [10 20], the second time it is [20 30], etc. Each repetition creates a '\' seen in the plot. When stitched together, it adds the vertical line connecting the parallel lines. Not sure if you need that or not, but the figure you attached had it so I included it.

[Cris LaPierre]

Omar

so, sir i'm really sorry

i know this is such a noucense to you, but i just can't get your code to work with mine.

could you please give me a hint on how to work through this.

[Cris LaPierre]

I am also confused by your code. That is why I opted to recreate the plot you attached rather than do something with the code you provided. Perhaps using your code, provide us with the following information:

1. How many parallel lines will be added to a plot (varialbe n in my code)
2. What is the horizontal spacing between these lines (varialbe dx in my code)

[omar mahallawy]

well that's the whole problem right there.

i have to keep updating my code always based on new things that come up, ie my code is not adapted to the new variables my fellow engineers keep updating me with, neither am i a coder, this is my first project.

anyways, the the number of parallel lines i need is named "numberofpumps" line 37 in my code.

the horizontal spacing between these lines, is called "distancebetweeneachpump" line 39 in my code.

please note that i have 13 numbers of each!!!

it's not just a number

matrix dimmensions won't agree!

[Cris LaPierre]

I'll take a look.

In the meantime, I'll give you the same suggestion I give all new MATLAB programmers. Consider going through MATLAB Onramp. It's free and will take you about 2 hours. It will orient you to the syntax needed for MATLAB. If this is your first time programming, it will also help you get started. There are 14 chapters, so feel free to just do the ones that are applicable. You start by performing simple calculations and creating variables and finish writing a program to calculate the speed of a planet.

[Cris LaPierre]

Try this. The main point of interest will be the new nested for loop at the bottom. However, I've gone through and cleaned up some other minor things in your code as well.

Q=3.3;
%gamma=8.43 kN/m3 = 859.62076503 Kg/m3 (*1000/9.81)
rouh=859.62076503;
g=9.81;
Gamma=rouh*g;
Zs=0;
Ze=0;
L=1285000;
Ks=0.000045; 
Er=1E-8;
viscosity=3.83E-3; 
% material grade X70
strength= 482000000;
%API 5L
D5L=0.0254 * [12.75 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 52 56 60 64 68 72 76 80]
V5L=(4*Q./(pi*D5L.^2));
V=V5L(V5L > 1 & V5L < 4.5)
Do=((4*Q)./(pi*V)).^(0.5)
Re=(V.*Do/viscosity)
Fo=0.01;
for I=0:1:10^6
    Fn=(1./(-4.*log10((Ks./(3.71*Do))+(1.26./(Re.*sqrt(Fo)))))).^2;
    E=abs((Fn-Fo)/Fn);
    if  E<=Er
        Fn=Fn(end);
        display(E);
        break
    end
    if E>Er
        Fo=Fn;
    end
end
    
Hloss=((Fn.*L.*Q.^2)./(12.*Do.^5))
Hpump=Hloss+Ze-Zs
PRESSURE=rouh.*g.*Hpump.*10.^(-5)
numberofpumps=ceil(PRESSURE./90)
pressureperpump=(PRESSURE./numberofpumps)
Distancebetweeneachpump=L./numberofpumps        
    
%calculating Hloss every 128500M
LC=1:128500:1285000;
for i=1:length(LC)
    HlossN=((Fn.*LC(i).*Q.^2)./(12.*Do.^5))
    TEL(i,:)=(Hpump-HlossN+Zs)
    HGL(i,:)=(TEL(i,:)-((V.^2)./(2.*g)))
    PE=Gamma.*(HGL-Ze)
    T=((PE(i).*Do)./(2.*strength))
end

for ii=1:length(Do)
    subplot(4,4,ii)
    hold on
    dx = Distancebetweeneachpump(ii)
    for n=1:numberofpumps(ii)
        plot(LC+(n-1)*dx,TEL(:,ii),'b')
        plot(LC+(n-1)*dx,HGL(:,ii),'r')
    end
    xlabel('LC')
    ylabel('HGL & TEL')
end

[Cris LaPierre]

Omar

isn't there a way when each line ends a verticle line goes verically up starting the new ( \ ) line?

[Cris LaPierre]

Wasn't sure you actually wanted those. To do that, modify the bottom for loop as follows:

for ii=1:length(Do)
    X=[]; Y1=[]; Y2=[];
    dx = Distancebetweeneachpump(ii);
    for n=1:numberofpumps(ii)
        X = [X LC+(n-1)*dx];
        Y1 = [Y1; TEL(:,ii)];
        Y2 = [Y2; HGL(:,ii)];
    end
    subplot(4,4,ii)
    hold on
    plot(X,Y1)
    plot(X,Y2)
    hold off
    xlabel('LC')
    ylabel('HGL & TEL')
end

[omar mahallawy]

but... how come when i calculated it manually the (\) line was verical and more of (/) but mainly verticle

[omar mahallawy]

is there a way i can make this line to be vertical?

please, don't get fed up of me

[Cris LaPierre]

You said the lines should be spaced Distancebetweeneachpump apart. Is that not the case? Or is your calculation of Distancebetweeneachpump incorrect? Or perhaps it has different units than LC, but how are we to know that?

If you prefer the lines be spaced end to end INSTEAD of Distancebetweeneachpump apart, update the line of code that sets dx to be

dx = LC(end);

[Cris LaPierre]

Ok, I dug in. I think you are making a mistake with your x values. You use all values of LC each time you plot a line segment. I think you need to have length(Do) number of points between each pump over a distance of dx, and numberofpumps line segments.

I assume the pumps are the cause of the vertical lines, and therefore should occur every dx. I also assume that the peaks should be gradually dropping as there will be some irrecoverable losses.

Not to thoroughly confuse you, but I've taken advantage of some linear algebra tricks to write this code:

Q=3.3;
%gamma=8.43 kN/m3 = 859.62076503 Kg/m3 (*1000/9.81)
rouh=859.62076503;
g=9.81;
Gamma=rouh*g;
Zs=0;
Ze=0;
L=1285000; % meters
Ks=0.000045; 
Er=1E-8;
viscosity=3.83E-3; 
% material grade X70
strength= 482000000;
%API 5L
D5L=0.0254 * [12.75 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 52 56 60 64 68 72 76 80]
V5L=(4*Q./(pi*D5L.^2));
V=V5L(V5L > 1 & V5L < 4.5)
Do=((4*Q)./(pi*V)).^(0.5)
Re=(V.*Do/viscosity)
Fo=0.01;
for I=0:1:10^6
    Fn=(1./(-4.*log10((Ks./(3.71*Do))+(1.26./(Re.*sqrt(Fo)))))).^2;
    E=abs((Fn-Fo)/Fn);
    if  E<=Er
        Fn=Fn(end);
        display(E);
        break
    end
    if E>Er
        Fo=Fn;
    end
end
    
Hloss=((Fn.*L.*Q.^2)./(12.*Do.^5))
Hpump=Hloss+Ze-Zs
PRESSURE=rouh.*g.*Hpump.*10.^(-5)
numberofpumps=ceil(PRESSURE./90)
pressureperpump=(PRESSURE./numberofpumps)
Distancebetweeneachpump=L./numberofpumps        
    
%calculating Hloss
for i=1:length(Distancebetweeneachpump)
    dx = Distancebetweeneachpump(i);
    LC=1:dx:L; % meters

    HlossN=(Fn*LC*Q.^2)./(12*Do.^5)';
    TEL=Hpump'-HlossN+Zs;
    HGL=TEL-(V.^2)'/(2*g);
    PE=Gamma*(HGL-Ze);
    T=(Do*PE)/(2*strength);

    X=[];
    for p = 1:numberofpumps(i)
       X=[X linspace(LC(p),LC(p)+dx,length(Do))];
    end
    subplot(4,4,i)
    hold on
    plot(X,TEL(:))
    plot(X,HGL(:))
    hold off
    xlabel('LC')
    ylabel('HGL & TEL')
end

[Cris LaPierre]

Since the linear algebra tricks at the end may be confusing, here is code that yields the same result but done using the syntax and variables you used

for i = 1:length(Distancebetweeneachpump)
    X=[]; Y1=[]; Y2=[];    
    dx = Distancebetweeneachpump(i);
    LC = 1:dx:L;
    for ii = 1:length(LC)
        HlossN=((Fn.*LC(ii).*Q.^2)./(12.*Do.^5));
        TEL(ii,:)=(Hpump-HlossN+Zs);
        HGL(ii,:)=(TEL(ii,:)-((V.^2)./(2.*g)));
        PE(ii,:)=Gamma.*(HGL(ii,:)-Ze);
        T(ii,:)=((PE(ii,:).*Do)./(2.*strength));
    
        X=[X linspace(LC(ii),LC(ii)+dx,length(Do))];
        Y1 = [Y1 TEL(ii,:)];
        Y2 = [Y2 HGL(ii,:)];
    end
    
    subplot(4,4,i)
    hold on
    plot(X,Y1)
    plot(X,Y2)
    hold off
    xlabel('LC')
    ylabel('HGL & TEL')
end