diff options
-rw-r--r-- | aberth/.gitignore | 1 | ||||
-rw-r--r-- | aberth/futhark.pkg | 4 | ||||
-rw-r--r-- | aberth/lib.fut | 54 |
3 files changed, 59 insertions, 0 deletions
diff --git a/aberth/.gitignore b/aberth/.gitignore index 60d8b01..66c7e62 100644 --- a/aberth/.gitignore +++ b/aberth/.gitignore @@ -1 +1,2 @@ aberth +lib/ diff --git a/aberth/futhark.pkg b/aberth/futhark.pkg new file mode 100644 index 0000000..963e457 --- /dev/null +++ b/aberth/futhark.pkg @@ -0,0 +1,4 @@ +require { + github.com/diku-dk/complex 0.1.2 #790bf261a6a36a9454b55f3f8109ac5cb1f4bf6e + github.com/diku-dk/cpprandom 1.1.4 #7dd47f3f2f5a8fa24d6847b34d9f8a9091b5d94a +} diff --git a/aberth/lib.fut b/aberth/lib.fut new file mode 100644 index 0000000..9e79197 --- /dev/null +++ b/aberth/lib.fut @@ -0,0 +1,54 @@ +import "lib/github.com/diku-dk/complex/complex" +import "lib/github.com/diku-dk/cpprandom/random" + +module uniform_real = uniform_real_distribution f64 minstd_rand +module rand_engine = minstd_rand + +module c64 = mk_complex f64 +type complex = c64.complex + +let N = 18i32 +let PolyN = 19i32 + +type poly = [PolyN]f64 + +let evaln_c (p: poly) (nterms: i32) (pt: complex): complex = + foldr (\coef accum -> c64.mk_re coef c64.+ pt c64.* accum) + (c64.mk_re p[nterms-1]) (take (nterms - 1) p) + +let eval_c (p: poly) (pt: complex): complex = evaln_c p (length p) pt + +let evaln_d (p: poly) (nterms: i32) (pt: f64): f64 = + foldr (\coef accum -> coef + pt * accum) + p[nterms-1] (take (nterms - 1) p) + +let eval_d (p: poly) (pt: f64): f64 = evaln_d p (length p) pt + +let derivative (p: poly): *poly = + map (\(i, v) -> f64.i32 i * v) (zip (1...PolyN-1) (take (PolyN - 1) p)) ++ [0] + +let max_root_norm (p: poly): f64 = + 1 + f64.maximum (map (\coef -> f64.abs (coef / p[PolyN-1])) p) + +module aberth = { + type approx = [N]complex + type state = {p: poly, deriv: poly, bound: poly, approx: approx, radius: f64} + + let gen_coord (r: f64) (rng: rand_engine.rng): (rand_engine.rng, f64) = + uniform_real.rand (-r, r) rng + + let gen_coord_c (r: f64) (rng: rand_engine.rng): (rand_engine.rng, complex) = + let (rng, x) = gen_coord r rng + let (rng, y) = gen_coord r rng + in (rng, c64.mk x y) + + let regenerate (rng: rand_engine.rng) (s: state): (rand_engine.rng, *approx) = + let rngs = rand_engine.split_rng N rng + let (rngs, approx) = unzip (map (gen_coord_c s.radius) rngs) + let rng = rand_engine.join_rng rngs + in (rng, approx) +} + + + +entry main: i32 = 42 |