Need help on using trapz on a definite integral

meu = 0.01; % acting friction during rolling

Radius_R = 21; % Radious of the roll die

kfm= Kfm(1:end,:); % kfm values for all passes

h_1 = h1(1:end,:); % height after reduction

h_0 = h0(1:end,:); % initial height

Delta_h = abs(h_1 - h_0); % relative height reduction

l_d = sqrt(Radius_R*Delta_h); % bite length

initX1 = 0; % bite angle at initial position

Xf = (tspan(rowOfMinValue))'; % bite angle at position Xf 1x201

Lenxf = length(Xf);

X_ld= l_d(1,1); % 1x1 element of xf

SigNach = y(:,1); % 11953x1 back tension

SigVOR = SigV; % 11953x201 front tension

for i = 1:Lenxf

%vRange for the first integration

R1 = initX1 : Xf(i,1);

% for the first integration the constant value is

int1 = SigNach -kfm(1,1);

% Range for the 2nd integration

R2 = Xf(i,1) :X_ld;

% constant for the second integration constant value is

int2 = SigVOR -kfm(1,1);

% first integration

Nach = trapz(R1,int1);

% second integration

Vor = trapz(R2,int1);

%

Final = Nach + Vor;

end

\\\ First of there is something wrong with dimentions in my code (i am beginner). i want to store the {Final = Nach + Vor;} for every values of x_f in a column.\\\\\

Answer 1

[Alan Stevens]

Replace

Final = Nach + Vor;

by

Final(i) = Nach + Vor;

[md mayeen uddin]

i am still getting error and the error messeges are below

Error using trapz (line 66)

Point spacing must be a scalar specifying uniform spacing or a vector of x-coordinates for each data point.

Error in ForceCalculation (line 31)

Vor = trapz(R2,int1);

[Alan Stevens]

I can't test your code as you haven't supplied all the data: e.g.Kfm, h1, h0 etc.

[md mayeen uddin]

file for SIgV is too big (11953x201). i tried several times to upload it and failed .the others are here

[Alan Stevens]

Try uploading a reduced set of values. Say 100 rows and 10 columns. Enough to test the process. (Make sure the other data sets are correspondingly smaller where appropriate).

[md mayeen uddin]

here is the 100x10 of SigV.

[Alan Stevens]

What does this mean:

Xf = (tspan(rowOfMinValue))'; 

What is rowOfMinValue? Have you defined a function called tspan?

What is y in:

SigNach = y(:,1); 

Even when I loaded your data into memory these problems arose! I'm still nowhere near getting to the point of identifying a trapz problem!

You could help us help you by making it easier to run your program. Get it to load the (reduced amount of) data with the appropriate variable names first and then upload the whole program.