Accumulating data in a loop while

Good evening, I need to collect data into an array with accumulation.

For example, there are 9 time values t=9, the array should look like this (0 t1 t1+t2 t1+t2+t3 and...) I want to do this in a loop so that it would be possible to regulate the number of t values.

So far I've thought of this, but it doesn't work correctly:

index=1;
n=10;
c=[];
while index<10
    t = b(index)+b(index+1)
    if t>b(index) && index<10
        t1=0;
        t1 = t + b(index)
        index=index+1;
    end
    c=[c t1];
end

Unrecognized function or variable 'b'.

c

[Dyuman Joshi]

Few things -

"b" is not defined.

You initialize "t1" as zero, but then over-write in the next line, which does not makes sense to me.

What are you trying to do? What is the objective? What is the code suppose to do?

You have added the tag "database" for this question - How does a database come into this question?

[gravy]

"b" this is part of the previous code

[gravy]

This is what it looks like in simple form

%t0=0;

%t1=delt0;

%t2=delt0+delt1;

%t3=delt0+delt1+delt2;

%t4=delt0+delt1+delt2+delt3;

%t5=delt0+delt1+delt2+delt3+delt4;

%t6=delt0+delt1+delt2+delt3+delt4+delt5;

%t7=delt0+delt1+delt2+delt3+delt4+delt5+delt6;

%t8=delt0+delt1+delt2+delt3+delt4+delt5+delt6+delt7;

%t9=delt0+delt1+delt2+delt3+delt4+delt5+delt6+delt7+delt8;

%t10=delt0+delt1+delt2+delt3+delt4+delt5+delt6+delt7+delt8+delt9;

%t = [t0 t1 t2 t3 t4 t5 t6 t7 t8 t9 t10];

I want to automate this process and not write new variables myself every time.

Here is the full code, maybe it will become clearer:

X = linspace(0,100,12);
for x = X    
    if (0<=x) && (x<5.5)
        y1=((x-0)/(5.5-0))*(7.74-9.19)+9.19;
        
    end
    
    if (5.5<=x) && (x<14.5)
        y2=((x-5.5)/(14.5-5.5))*(6.45-7.74)+7.74;
        
    end
    if (14.5<=x) && (x<22.5)
        y3=((x-14.5)/(22.5-14.5))*(5.56-6.45)+6.45;
        
    end
    if (22.5<=x) && (x<30)
        y4=((x-22.5)/(30-22.5))*(4.79-5.56)+5.56;
        
    end
    if (30<=x) && (x<43.5)
        y5=((x-30)/(43.5-30))*(3.43-4.79)+4.79;
        
    end
    if (43.5<=x) && (x<49)
        y6=((x-43.5)/(49-43.5)).*(3.04-3.43)+3.43;
        
    end
    if (49<=x) && (x<56)
        y7=((x-49)/(56-49))*(2.39-3.04)+3.04;
        
    end
    if (56<=x) && (x<64)
        y8=((x-56)/(60-56)).*(0.8-2.39)+2.39;
        
    end
    if (64<=x) && (x<73)
        y9=((x-60)/(70-60))*(-1.98-0.8)+0.8;
        
    end
    if (73<=x) && (x<83)
        y10=((x-70)/(80-70))*(-3.88+1.98)-1.98;
        
    end
    if (83<=x) && (x<93)
        y11=((x-80)/(90-80))*(-5.45+3.88)-3.88;
        
    end
    if (93<=x) && (x<=100)
        y12=((x-90)/(100-90))*(-6.74+5.45)-5.45;
        
    end
end
Y=[y1 y2 y3 y4 y5 y6 y7 y8 y9 y10 y11 y12];
X = linspace(0,100,12);
v = [ 0:10:100 ];
delv=10;
dzeta = 120;
w0=0;
v1=0;
a=[];
while v1<100 %&& w0<3
    fycp = abs(((interp1(X,Y,v1)-w0)+((interp1(X,Y,v1+delv))-w0)))/2;
    v1=v1+10;
    %  w0=w0+1;
    a=[a fycp];
    
end
b=[];
index=1;
while index<11
    delt = delv/(dzeta*a(index));
    index=index+1;
    b=[b delt];
end

index=1;
n=10;
c=[];
while index<10
    t = b(index)+b(index+1)
    if t>b(index) && index<10
        t1=0;
        t1 = t + b(index)
        index=index+1;
    end
    c=[c t1];
end

Answer 1

[Voss]

t = rand(1,9) % 9 random t values

t = 1×9

0.7787 0.5803 0.4362 0.3903 0.0329 0.8313 0.1897 0.7956 0.7963

c = cumsum([0 t]) % c = [0, t(1), t(1)+t(2), t(1)+t(2)+t(3), etc.]

c = 1×10

0 0.7787 1.3590 1.7951 2.1854 2.2183 3.0496 3.2394 4.0349 4.8312

[gravy]

You yourself assigned indices 1,2,3, etc., but I want the program to add the next value to the previous one, and I could regulate the number of “indices” myself.

[Voss]

It seems like you want to cumulatively sum the t where the next b is positive, based on this:

t = b(index)+b(index+1)

if t>b(index) && index<10

That is, given that t = b(index)+b(index+1), then t>b(index) implies b(index+1)>0.

b = randn(1,10) % 10 random b values, some of which are negative

b = 1×10

-0.7297 -0.1824 0.8041 1.0788 -0.7439 -0.8178 1.7741 0.2454 -1.5478 -1.7278

t = rand(1,9)   % 9 random t values

t = 1×9

0.2471 0.7733 0.9757 0.7641 0.3566 0.9937 0.5369 0.1627 0.0781

idx = find(b > 0);
if ~isempty(idx) && idx(1) == 1
    idx(1) = [];
end
c = cumsum([0 t(idx-1)]) % cumulatively sum the elements of t where the next b is positive

c = 1×5

0 0.7733 1.7490 2.7427 3.2796

[gravy]

still not the same, it should look like you wrote before:

t = rand(1.9) % 9 random t values

c = cumsum([0 t]) % c = [0, t(1), t(1)+t(2), t(1)+t(2)+t(3), etc.]

But the summation in the array should be done automatically, I want to change the value of t, but not rewrite the array every time. There will be a graph with "b" and "c" and their number in the array should converge.

I tried to set some kind of condition, but I couldn’t figure it out yet.

[gravy]

I'm an idiot, your previous answer was correct. Thanks a lot