Theorem 22 (Round-off error)
By decreasing the step size, one needs more calculations to reach a given value of
, and hence the effects of round-off error become important. The effect of round-off error is estimated in the following theorem, given without proof:
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Assume
is continuous and satisfies a Lipschitz Condition in the variable
on the domain
.
Assume a constant
exists such that
for all
in
,
and let
be the unique solution to the initial value problem
,
and call
the successive approximations generated by Euler's method for some positive integer
, for the perturbed problem
,
with
and
.
Then for each
, we have
.
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From this result, it is clear that the total error will increase for sufficiently small values of
.
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