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  1. Fabio Kopp

    C/++/# How to integrate when one of the limits is a variable?

    By the way, I was disregarding one big thing. The routines of integration were in different files(the definition in .cpp and the declaration in .hpp), so in this way, the approach that I was using would never work indeed. I've tried this simple case rekcha (7) (for constants) from this site...
  2. Fabio Kopp

    C/++/# How to integrate when one of the limits is a variable?

    Chris, now I found the right solution and what is the meaning of a grid in your answer. By the way, the 3 questions I have already solved. The question 1 I solved using the trick https://en.wikipedia.org/wiki/Integration_by_substitution like in example 1, but for a different parameterization...
  3. Fabio Kopp

    C/++/# How to integrate when one of the limits is a variable?

    Mark44, this is a forum. If you don't know, it is used to make question and get answers. If you don't want to answer the questions, ok. Or if it is more agreeable to you, imagine that all humans are stupids (except you) and you are the next Alan Turin to save the world. And as a see in a...
  4. Fabio Kopp

    C/++/# How to integrate when one of the limits is a variable?

    When I compile this code(for a function with only one variable x), it's works properly. Mark44, you are looking for the "mistakes" on my code example and you are not giving me a clear answer, even it seems ugly to a professional programmer like you, i'm newbie. If the ugly way works, the next...
  5. Fabio Kopp

    C/++/# How to integrate when one of the limits is a variable?

    result = qromb(func, a, b) -> rotine to integration where a is the inferior limit and b the superior. DP -> is double in the numerical recipes library. Could you show me a simple example of the use of pointers for this case?
  6. Fabio Kopp

    C/++/# How to integrate when one of the limits is a variable?

    You are right about the declaration of global variable. As I told before, in fortran 77 I use common/v/y inside the func0 and func1 and the both integrations are done properly. And in python we could use args=(y) that is used to pass the arguments.
  7. Fabio Kopp

    C/++/# How to integrate when one of the limits is a variable?

    I was looking on the the internet about this method of integration, but it is unclear to me how to apply it through a simple example. I have already solved my problem using the change of variable. Do you have a simple example in fortran, python or c++ for I study it? Now, I'm still trying to...
  8. Fabio Kopp

    C/++/# How to integrate when one of the limits is a variable?

    You're right. I was looking on the internet for one solution and substitution method is needed in this case: https://en.wikipedia.org/wiki/Integration_by_substitution. Thanks anyway.
  9. Fabio Kopp

    C/++/# How to integrate when one of the limits is a variable?

    I'm trying to integrate a simple function (x*y) using the Romberg method. Question 1: I want to integrate only x and maintain the argument y present in the rest of calculation, like a global variable. In fortran 77 I would use common. Question 2: How to integrate using arguments in the...
  10. Fabio Kopp

    How to obtain a function from gsl library integration?

    I have found the solution for this problem and the code is the following. #include<iostream> #include<gsl/gsl_math.h> #include <gsl/gsl_monte_vegas.h> #include <gsl/gsl_monte.h> using namespace std; struct my_f_params { double a; double b; double c; }; double my_f (double x[], size_t dim...
  11. Fabio Kopp

    How to obtain a function from gsl library integration?

    I am having some problems to use the gsl library. I do the integration via monte carlo and I have obtained the right result, but a need to know how to use this result when I have a dependence on another variable. For example, f(x,y)=x*y, but the integration is only on x. Because I want to...
  12. Fabio Kopp

    Problem to derive the KG propagator

    The problem was solved. How do I remove this post from the forum?
  13. Fabio Kopp

    Problem to derive the KG propagator

    Homework Statement I'm using the text-book Student Friendly Quantum Field Theory [Robert D. Klauber] and I don't know how to get the function (k0) (3-134) present in the figure below. http://[url=http://postimg.org/image/5j62c27nz/][PLAIN]http://s11.postimg.org/5j62c27nz/help.jpg [Broken]...
  14. Fabio Kopp

    Is there a w+(L or R)?

    Thanks for the help!
  15. Fabio Kopp

    Is there a w+(L or R)?

    I already done that study. But my doubt remains. Maybe this picture illustrate my doubt. Which are the quantum numbers(T,T^3,Y) of the gauge boson W before and after interaction with h0?. This picture is from Quarks and Leptons (Halzen & Martin) chapter 15, section 4. PS: T -> weak isospin...
  16. Fabio Kopp

    Is there a w+(L or R)?

    I'm looking for the Isospin, isospin(third component) and the hypercharge of gauge boson W+- before and after the interaction with Higgs scalar field (h0). Because is there no mention of it in Halzen's book, Griffths'book and Greiner's book of electroweak interactions.
  17. Fabio Kopp

    Is there a w+(L or R)?

    I was studying the interaction of Higgs field with the Right-Handed particles, and I don't know how to determine the quantum numbers before and after the boson W+- interaction with the component of Higgs scalar Field (h0). I am following the Halzen's book. The h0 has the following quantum...
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