definite integral of numerical vectors

i'm looking for to solve a definite integral of two vectors

I know: z vector of numbers and G(z) vector of numbers. The limits of integration are zmin and zmax

I should to calculate: Integral between zmin,zmax of [G(z) * z^(7/6)] dz

Answer 1

[Mahesh]

I think you have to use numerial method of integration such as simpson rule or trapezoidal rule. Make a routine for either of these methods and calculate them for each z values and add up. If sum over them, you will get the answer. I hope it works for you. Let me know if you have problem on making subroutine.

Goof luck.

[Star Strider]

If you have vectors of numbers rather than functions, integral will not work. As Mahesh suggests, use the trapz function instead.

[Stefano]

Thank you, could you give me an example? I would to obtain another vector as result

[Star Strider]

The way you have defined your data (as I understand it anyway), you have one vector created by multiplying element-by-element the vector for G(z) (that you have already defined as a vector) and the vector z^(7/6). Integrating it will only give you a vector if you use cumtrapz.

This is how I understand what you want to do:

zmin = 0;
zmax = 100;
z = linspace(zmin,zmax);    % Create ‘z’ (arbitrary)
Gz = exp(-z);               % Create ‘G(z)’ (arbitrary)
Dg = [Gz .* z.^(7/6)];      % Create vector to integrate

Ig = trapz(z, Dg)           % Do the integration

The value of the integral is returned in Ig.

If G(z) is an array instead of a vector, Ig will be a vector.

[Stefano]

Thank you!

[Star Strider]

My pleasure!