diff options
| author | Simon Marlow <simonmar@microsoft.com> | 2006-10-12 11:07:11 +0000 |
|---|---|---|
| committer | Simon Marlow <simonmar@microsoft.com> | 2006-10-12 11:07:11 +0000 |
| commit | fcf6ab7b3dfe389e971059bbf21dfa8179b20f5e (patch) | |
| tree | 1a5eaddc896c2f1c061e640055b8e42ab4837707 /docs/users_guide/parallel.xml | |
| parent | 8c2549461d624ad5cfec9be3266bdfd016371658 (diff) | |
| download | haskell-fcf6ab7b3dfe389e971059bbf21dfa8179b20f5e.tar.gz | |
fix definition of fib in example code
Diffstat (limited to 'docs/users_guide/parallel.xml')
| -rw-r--r-- | docs/users_guide/parallel.xml | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/docs/users_guide/parallel.xml b/docs/users_guide/parallel.xml index 3d14622cf1..7792ea651a 100644 --- a/docs/users_guide/parallel.xml +++ b/docs/users_guide/parallel.xml @@ -136,7 +136,7 @@ import Control.Parallel nfib :: Int -> Int nfib n | n <= 1 = 1 - | otherwise = par n1 (seq n2 (n1 + n2 + 1)) + | otherwise = par n1 (seq n2 (n1 + n2)) where n1 = nfib (n-1) n2 = nfib (n-2)</programlisting> @@ -149,8 +149,8 @@ nfib n | n <= 1 = 1 (leaving the parent to evaluate the other branch). Also, we must use <function>seq</function> to ensure that the parent will evaluate <varname>n2</varname> <emphasis>before</emphasis> <varname>n1</varname> - in the expression <literal>(n1 + n2 + 1)</literal>. It is not sufficient - to reorder the expression as <literal>(n2 + n1 + 1)</literal>, because + in the expression <literal>(n1 + n2)</literal>. It is not sufficient + to reorder the expression as <literal>(n2 + n1)</literal>, because the compiler may not generate code to evaluate the addends from left to right.</para> |