blob: bffef2c6df246a635e76b5bc35521ecdc32cb908 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
|
-- This is the integral benchmark from the nofib benchmark suite.
-- In the past there have been issues with numeric stability for this benchmark (see #19569)
-- so I added it to testsuite to catch such regressions in the future.
-- It might be acceptable for this test to fail if you make changes to the simplifier. But generally such a failure shouldn't be accepted without good reason.
-- The excessive whitespace is the result of running the original benchmark which was a .lhs file through unlit.
module Main (integrate1D, main) where
import System.Environment
integrate1D :: Double -> Double -> (Double->Double) -> Double
integrate1D l u f =
let d = (u-l)/8.0 in
d * sum
[ (f l)*0.5,
f (l+d),
f (l+(2.0*d)),
f (l+(3.0*d)),
f (l+(4.0*d)),
f (u-(3.0*d)),
f (u-(2.0*d)),
f (u-d),
(f u)*0.5]
integrate2D l1 u1 l2 u2 f = integrate1D l2 u2
(\y->integrate1D l1 u1
(\x->f x y))
zark u v = integrate2D 0.0 u 0.0 v (\x->(\y->x*y))
-- type signature required for compilers lacking the monomorphism restriction
ints = [1.0..] :: [Double]
zarks = zipWith zark ints (map (2.0*) ints)
rtotals = head zarks : zipWith (+) (tail zarks) rtotals
rtotal n = rtotals!!n
is = map (^4) ints
itotals = head is : zipWith (+) (tail is) itotals
itotal n = itotals!!n
es = map (^2) (zipWith (-) rtotals itotals)
etotal n = sum (take n es)
-- The (analytical) result should be zero
main = do
[with_output,range] <- getArgs
if (read with_output)
then putStrLn $ show $ etotal $ read range
else seq (etotal $ read range) (putStrLn "Exact result hidden for lack of stability.\nPass 'True' as first argument to the benchmark if you want to view the computed output for testing purposes.")
|
