Lab for Romberg Integration

Module for Romberg Integration

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Romberg Integration for Quadrature Quadrature Rule for Numerical Integration.

To approximate the integral [Graphics:rq.txtgr1.gif]

by generating a table of approximations, and using [Graphics:rq.txtgr2.gif] as the final answer.
The approximations [Graphics:rq.txtgr3.gif] are stored in a special lower triangular matrix.
The elements [Graphics:rq.txtgr4.gif] of the first column are computed using the sequential trapezoidal rule
based on [Graphics:rq.txtgr5.gif] subintervals of [Graphics:rq.txtgr6.gif]; then [Graphics:rq.txtgr7.gif] is computed using Romberg's rule.
Elements of row j are [Graphics:rq.txtgr8.gif].
The algorithm is terminated early when [Graphics:rq.txtgr9.gif].

[Graphics:rq.txtgr11.gif][Graphics:rq.txtgr10.gif]
 
 

Report to be handed in.

Computer Projects.

 

Project I. Construct the Romberg table for finding [Graphics:rq.txtgr12.gif] .

[Graphics:rq.txtgr11.gif][Graphics:rq.txtgr13.gif]

Exercise 1. Plot the function over the interval [0, 1.25].

[Graphics:rq.txtgr11.gif][Graphics:rq.txtgr14.gif]

[Graphics:rq.txtgr11.gif][Graphics:rq.txtgr15.gif]

Exercise 2. Construct the Romberg table using tol = 0.001

[Graphics:rq.txtgr11.gif][Graphics:rq.txtgr16.gif]
[Graphics:rq.txtgr11.gif][Graphics:rq.txtgr17.gif]

Exercise 3. The last entry in the table is Rj,j. Let's find it.

[Graphics:rq.txtgr11.gif][Graphics:rq.txtgr18.gif]

Exercise 4. Look at 10 digits in Rj,j.

[Graphics:rq.txtgr11.gif][Graphics:rq.txtgr19.gif]

Exercise 5. Are all 10 digits correct ? Why ?
How many digits can you guarantee based on the computations involving rows 1-4 of the table ?

Exercise 6. Determine how to get Romberg integration to achieve 10 digits of accuracy.
How many rows of the Romberg table do you think will be needed ?
Do it.
Report the answer with 10 digits of accuracy.


Project II. Construct the Romberg table for finding [Graphics:rq.txtgr20.gif] .

[Graphics:rq.txtgr11.gif][Graphics:rq.txtgr21.gif]

Exercise 7. Plot the function over the interval [0, 1].

[Graphics:rq.txtgr11.gif][Graphics:rq.txtgr22.gif]

[Graphics:rq.txtgr11.gif][Graphics:rq.txtgr23.gif]

Exercise 8. Construct the Romberg table using tol = 0.001

[Graphics:rq.txtgr11.gif][Graphics:rq.txtgr24.gif]
[Graphics:rq.txtgr11.gif][Graphics:rq.txtgr25.gif]

Exercise 9. The last entry in the table is Rj,j. Let's find it.

[Graphics:rq.txtgr11.gif][Graphics:rq.txtgr26.gif]

Exercise 10. Look at 10 digits in Rj,j.

[Graphics:rq.txtgr11.gif][Graphics:rq.txtgr27.gif]

Exercise 11. Are all 10 digits correct ? Why ?
How many digits can you guarantee based on the computations involving rows 1-4 of the table ?

Exercise 12. Determine how to get Romberg integration to achieve 10 digits of accuracy.
How many rows of the Romberg table do you think will be needed ?
Do it.
Report the answer with 10 digits of accuracy.

 

 

 

(c) John H. Mathews, 1998