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static evaluation (50% cpu improvement over utm_of)

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This commit is contained in:
Pascal Brisset
2007-04-26 22:08:04 +00:00
parent dcdd39a50d
commit 7b67c67a3b
2 changed files with 76 additions and 35 deletions
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sw/lib/ocaml/latlong.ml
+75 -35
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@@ -236,34 +236,57 @@ let coeff_proj_mercator_inverse =
[|0.;0.;0.; 17./.30720.;283./.430080.|];
[|0.;0.;0.;0.;4397./.41287680.|]|];;
let utm_of geo ({posn_long = lambda; posn_lat = phi} as pos) =
if not (valid_geo pos) then
invalid_arg "Latlong.utm_of";
let utm_of' = fun geo ->
let ellipsoid = ellipsoid_of geo in
let k0 = 0.9996
and xs = 500000. in
let lambda_deg = truncate (floor ((Rad>>Deg)lambda)) in
let zone = (lambda_deg + 180) / 6 + 1 in
let lambda_c = (Deg>>Rad) (float (lambda_deg - ((lambda_deg mod 6)+6)mod 6 + 3)) in
let e = ellipsoid.e
and n = k0 *. ellipsoid.a in
let ll = latitude_isometrique phi e
and dl = lambda -. lambda_c in
let phi' = asin (sin dl /. cosh ll) in
let ll' = latitude_isometrique phi' 0. in
let lambda' = atan (sinh ll /. cos dl) in
let z = C.make lambda' ll'
and c = serie5 coeff_proj_mercator e in
let z' = ref (C.scal c.(0) z) in
for k = 1 to Array.length c - 1 do
z' := C.add !z' (C.scal c.(k) (C.sin (C.scal (float (2*k)) z)))
done;
z' := C.scal n !z';
{ utm_zone = zone; utm_x = xs +. C.im !z'; utm_y = C.re !z' };;
let c = serie5 coeff_proj_mercator e in
fun ({posn_long = lambda; posn_lat = phi} as pos) ->
if not (valid_geo pos) then
invalid_arg "Latlong.utm_of";
let lambda_deg = truncate (floor ((Rad>>Deg)lambda)) in
let zone = (lambda_deg + 180) / 6 + 1 in
let lambda_c = (Deg>>Rad) (float (lambda_deg - ((lambda_deg mod 6)+6)mod 6 + 3)) in
let ll = latitude_isometrique phi e
and dl = lambda -. lambda_c in
let phi' = asin (sin dl /. cosh ll) in
let ll' = latitude_isometrique phi' 0. in
let lambda' = atan (sinh ll /. cos dl) in
let z = C.make lambda' ll' in
let z' = ref (C.scal c.(0) z) in
for k = 1 to Array.length c - 1 do
z' := C.add !z' (C.scal c.(k) (C.sin (C.scal (float (2*k)) z)))
done;
z' := C.scal n !z';
{ utm_zone = zone; utm_x = xs +. C.im !z'; utm_y = C.re !z' };;
(* Benchmarks with limited bound on the for loop:
utm_of WGS84 {posn_lat = 0.8; posn_long = 0.1 };;
4: {utm_x = 711976.494998118491; utm_y = 5079519.01467700768; utm_zone = 31}
3: {utm_x = 711976.494993993081; utm_y = 5079519.01467550546; utm_zone = 31}
2: {utm_x = 711976.49488538783; utm_y = 5079519.02243153844; utm_zone = 31}
1: {utm_x = 711977.141232272843; utm_y = 5079519.25322676543; utm_zone = 31}
0: {utm_x = 711985.538644456305; utm_y = 5074176.83014749549; utm_zone = 31}
let of_utm geo { utm_zone = f; utm_x = x; utm_y = y } =
if x < 0. || x > 1e6 || y < -10e6 || y > 10e6 || f < 0 || f > 60 then
invalid_arg "Latlong.of_utm";
==> centimetric precision with 2 (i.e. using c(0), c(1) and c(2)
*)
(** Static evaluation for better performance (~50% for cputime) *)
let utm_of =
let u_WGS84 = utm_of' WGS84
and u_NTF = utm_of' NTF
and u_ED50 = utm_of' ED50
and u_NAD27 = utm_of' NAD27 in
fun geo -> match geo with
WGS84 -> u_WGS84
| NTF -> u_NTF
| ED50 -> u_ED50
| NAD27 -> u_NAD27
let of_utm' geo =
let ellipsoid = ellipsoid_of geo in
let k0 = 0.9996
and xs = 500000.
@@ -271,19 +294,36 @@ let of_utm geo { utm_zone = f; utm_x = x; utm_y = y } =
let e = ellipsoid.e
and n = k0 *. ellipsoid.a in
let c = serie5 coeff_proj_mercator_inverse e in
let lambda_c = (Deg>>Rad) (float (6 * f - 183)) in
let z' = C.scal (1./.n/.c.(0)) (C.make (y-.ys) (x-.xs)) in
let z = ref z' in
for k = 1 to Array.length c - 1 do
z := C.sub !z (C.scal c.(k) (C.sin (C.scal (float (2*k)) z')))
done;
let ll = C.re !z and lls = C.im !z in
let lambda = lambda_c +. atan (sinh lls /. cos ll)
and phi' = asin (sin ll /. cosh lls) in
let ll = latitude_isometrique phi' 0. in
let phi = inverse_latitude_isometrique ll e 1e-11 in
{posn_long = lambda; posn_lat = phi};;
fun { utm_zone = f; utm_x = x; utm_y = y } ->
if x < 0. || x > 1e6 || y < -10e6 || y > 10e6 || f < 0 || f > 60 then
invalid_arg "Latlong.of_utm";
let lambda_c = (Deg>>Rad) (float (6 * f - 183)) in
let z' = C.scal (1./.n/.c.(0)) (C.make (y-.ys) (x-.xs)) in
let z = ref z' in
for k = 1 to Array.length c - 1 do
z := C.sub !z (C.scal c.(k) (C.sin (C.scal (float (2*k)) z')))
done;
let ll = C.re !z and lls = C.im !z in
let lambda = lambda_c +. atan (sinh lls /. cos ll)
and phi' = asin (sin ll /. cosh lls) in
let ll = latitude_isometrique phi' 0. in
let phi = inverse_latitude_isometrique ll e 1e-11 in
{posn_long = lambda; posn_lat = phi};;
(** Static evaluation for better performance (~50% for cputime) *)
let of_utm =
let u_WGS84 = of_utm' WGS84
and u_NTF = of_utm' NTF
and u_ED50 = of_utm' ED50
and u_NAD27 = of_utm' NAD27 in
fun geo -> match geo with
WGS84 -> u_WGS84
| NTF -> u_NTF
| ED50 -> u_ED50
| NAD27 -> u_NAD27
let (<<) geo1 geo2 ({posn_long = lambda; posn_lat = phi} as pos) =
sw/lib/ocaml/latlong.mli
+1
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@@ -92,6 +92,7 @@ val of_lambert : lambert_zone -> lambert -> ntf
val lambert_of : lambert_zone -> ntf -> lambert
(** Conversions between geographic (in NTF) and lambert *)
val utm_of' : geodesic -> geographic -> utm
val utm_of : geodesic -> geographic -> utm
val of_utm : geodesic -> utm -> geographic
(** Conversions between geographic and UTM. May raise Invalid_argument. *)