21.04.2015 Views

The Computable Differential Equation Lecture ... - Bruce E. Shapiro

The Computable Differential Equation Lecture ... - Bruce E. Shapiro

The Computable Differential Equation Lecture ... - Bruce E. Shapiro

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

190 CHAPTER 9. DIFFERENTIAL ALGEBRAIC EQUATIONS<br />

where [w(i)] i=1,...,s represents the vector of components indexed by i. Define<br />

⎛<br />

⎞<br />

g(t n−1 + c 1 h) − g(t n−1 )<br />

G = 1 g(t n−1 + c 2 h) − g(t n−1 )<br />

⎜<br />

⎟<br />

h ⎝ . ⎠<br />

g(t n−1 + c s h − g(t n−1 )<br />

(9.221)<br />

so that<br />

<strong>The</strong>n from equation 9.212,<br />

V ′ = A −1 G (9.222)<br />

v n = v n−1 + hb T V ′ (9.223)<br />

= g(t n−1 ) + hb T A −1 G (9.224)<br />

<strong>The</strong> local error is thus<br />

d n = g(t n−1 ) + hb T A −1 G − g(t n ) (9.225)<br />

)<br />

= −<br />

(hg ′ + h2<br />

2 g′′ + h3<br />

6 g′′′ + · · ·<br />

(9.226)<br />

⎛<br />

c 1 hg ′ + c2 1 h2<br />

2 g′′ + c3 1 h3 ′′′<br />

g + · · ·<br />

+ b T A −1 ⎜<br />

⎝<br />

.<br />

⎟ (9.227)<br />

c s hg ′ + c2 s h2<br />

2 g′′ + c3 2 h3 ′′′<br />

⎠<br />

g + · · ·⎞<br />

Definition 9.14. <strong>The</strong> algebraic order of an IRK method is equal to k if d n =<br />

O(h k+1 ) for all components.<br />

<strong>The</strong>orem 9.16. <strong>The</strong> algebraic order of an IRK method equal to k if and only if<br />

where<br />

b T A −1 c j = 1, for j = 1, . . . , k (9.228)<br />

We state the remaining results without proof.<br />

c j = (c j 1 , . . . , cj s) T (9.229)<br />

Definition 9.15. A perturbation (z n , δ 0 , . . . , δ s+1 ) of the method for y n ,<br />

⎛<br />

⎞<br />

s∑<br />

F ⎝t n−1 + c i h, y n−1 + h a ij Y j, ′ Y i<br />

′ ⎠ = 0 (9.230)<br />

j=1<br />

s∑<br />

y n = y n−1 + h b i Y i ′ (9.231)<br />

i=1<br />

Math 582B, Spring 2007<br />

California State University Northridge<br />

c○2007, B.E.<strong>Shapiro</strong><br />

Last revised: May 23, 2007

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!