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open Ast
(*
--# Natural logarithm
--#
--# Calculates the natural logarithm (base e) of x.
--#
--# @name log
--# @param x :: Number | Vector | NDArray The input value (must be positive).
--# @param na_ignore :: Bool Whether to preserve NA values in inputs. Default is false.
--# @return :: Float | Vector | NDArray The natural logarithm.
--# @example
--# log(2.71828)
--# -- Returns = ~1.0
--# @family math
--# @seealso exp
--# @export
*)
let register env =
Env.add "log"
(make_builtin_named ~name:"log" ~variadic:true 1 (fun named_args _env ->
match Math_common.get_bool_flag "na_ignore" false named_args with
| Error e -> e
| Ok na_ignore ->
let args = Math_common.positional_args_without [ "na_ignore" ] named_args in
match args with
| [VInt n] ->
if n <= 0 then Error.value_error "Function `log` is undefined for non-positive numbers."
else VFloat (Float.log (float_of_int n))
| [VFloat f] ->
if f <= 0.0 then Error.value_error "Function `log` is undefined for non-positive numbers."
else VFloat (Float.log f)
| [VVector arr] ->
let result = Array.make (Array.length arr) (VNA NAGeneric) in
let had_error = ref None in
Array.iteri (fun i v ->
if !had_error = None then
match v with
| VInt n ->
if n <= 0 then had_error := Some (Error.value_error "Function `log` is undefined for non-positive numbers.")
else result.(i) <- VFloat (Float.log (float_of_int n))
| VFloat f ->
if f <= 0.0 then had_error := Some (Error.value_error "Function `log` is undefined for non-positive numbers.")
else result.(i) <- VFloat (Float.log f)
| VNA na_t when na_ignore -> result.(i) <- VNA na_t
| VNA _ -> had_error := Some (Error.na_value_error "log")
| _ -> had_error := Some (Error.type_error "Function `log` requires numeric values.")
) arr;
(match !had_error with Some e -> e | None -> VVector result)
| [VNDArray arr] ->
let result = Array.map (fun f ->
if f <= 0.0 then nan
else Float.log f
) arr.data in
if Array.exists Float.is_nan result then
Error.value_error "Function `log` encountered non-positive values in NDArray."
else
VNDArray { shape = arr.shape; data = result }
| [VNA na_t] when na_ignore -> VNA na_t
| [VNA _] -> Error.na_value_error "log"
| [_] -> Error.type_error "Function `log` expects a number, numeric Vector, or NDArray."
| _ -> Error.arity_error_named "log" 1 (List.length args)
))
env