Gaussian Integration: Int(0,1000)g(x)[f(x)]dx

In summary, Gaussian integration is a method for approximating definite integrals using a weighted sum of function values at specific points within the integration interval. It is more accurate and efficient than other numerical integration methods, and the number of quadrature points needed depends on the degree of the polynomial being integrated and the desired accuracy. It can also be used for improper integrals, but may require more quadrature points for accuracy.
  • #1
eljose79
1,518
1
I have some doubts about it..in fact when you want to calculate an integral numerically..i always use gaussian integration but what would happen if i use this technique to calculate:

Int(0,1000)g(x)[f(x)]dx where [] means the floor function in fact it is a non-continuous function..would be gaussian integration valid in this case?...
 
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  • #2
It would still be valid, but you'd be better off doing the integral separately for each interval between the jumps.
 
  • #3


Gaussian integration is a numerical method used to approximate integrals by breaking them down into smaller intervals and using a weighted sum of function values at specific points within each interval. This method is typically used for continuous functions, as the weights and points are chosen based on the function's smoothness.

In the case of a non-continuous function, such as one with a floor function, Gaussian integration may not be the most accurate method. This is because the points and weights are chosen based on the function's smoothness, and a non-continuous function may not have a well-defined smoothness.

However, it is still possible to use Gaussian integration for non-continuous functions by modifying the weights and points to better fit the function's behavior. This may require some trial and error, as there is no set formula for choosing the weights and points in this case.

Alternatively, there are other numerical integration methods that may be better suited for non-continuous functions, such as the trapezoidal rule or Simpson's rule. These methods may be more accurate and efficient for calculating integrals involving non-continuous functions.

In summary, while Gaussian integration is a commonly used method for numerical integration, it may not be the best choice for non-continuous functions. It is important to consider the behavior of the function and choose an appropriate integration method for accurate results.
 

1. What is Gaussian integration?

Gaussian integration is a numerical method used to approximate the value of a definite integral, specifically in the form of Int(a,b)g(x)[f(x)]dx, where g(x) is a weight function and f(x) is a function to be integrated.

2. How does Gaussian integration work?

Gaussian integration uses a weighted sum of function values at specific points within the integration interval to approximate the integral. These points, known as the Gaussian quadrature points, are chosen in such a way that the approximation is accurate for polynomials of a certain degree.

3. What are the advantages of Gaussian integration?

Gaussian integration is typically more accurate than other numerical integration methods, such as the trapezoidal rule or Simpson's rule. It also requires less function evaluations, making it more efficient for higher-dimensional integrals.

4. How do I choose the number of quadrature points for Gaussian integration?

The number of quadrature points needed for Gaussian integration depends on the degree of the polynomial being integrated and the desired level of accuracy. As a general rule, a higher degree polynomial and a higher desired accuracy will require more quadrature points.

5. Can Gaussian integration be used for improper integrals?

Yes, Gaussian integration can be used to approximate improper integrals by extending the integration interval to infinity and then using a change of variable. However, this approach may require a larger number of quadrature points to ensure accuracy.

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