gleam_synapses

-module(gleam_synapses@model@mathematics).
-compile(no_auto_import).

-export([exp/1, log/1, tanh/1, dot_product/2, root_mean_square_error/1, accuracy/1]).

-spec exp(float()) -> float().
exp(A) ->
    math:exp(A).

-spec log(float()) -> float().
log(A) ->
    math:log(A).

-spec tanh(float()) -> float().
tanh(A) ->
    math:tanh(A).

-spec dot_product(
    gleam_zlists@interop:z_list(float()),
    gleam_zlists@interop:z_list(float())
) -> float().
dot_product(Left, Right) ->
    _pipe = gleam_zlists:zip(Left, Right),
    _pipe@1 = gleam_zlists:map(
        _pipe,
        fun(X) ->
            {A, B} = X,
            A
            * B
        end
    ),
    gleam_zlists:sum(_pipe@1).

-spec euclidean_distance(
    gleam_zlists@interop:z_list(float()),
    gleam_zlists@interop:z_list(float())
) -> float().
euclidean_distance(Xs, Ys) ->
    {ok, Res@1} = case begin
        _pipe = Xs,
        _pipe@1 = gleam_zlists:zip(_pipe, Ys),
        _pipe@2 = gleam_zlists:map(
            _pipe@1,
            fun(T) ->
                {X, Y} = T,
                Diff = X
                - Y,
                Diff
                * Diff
            end
        ),
        _pipe@3 = gleam_zlists:sum(_pipe@2),
        gleam@float:square_root(_pipe@3)
    end of
        {ok, Res} -> {ok, Res};
        _try ->
            erlang:error(#{gleam_error => assert,
                           message => <<"Assertion pattern match failed"/utf8>>,
                           value => _try,
                           module => <<"gleam_synapses/model/mathematics"/utf8>>,
                           function => <<"euclidean_distance"/utf8>>,
                           line => 26})
    end,
    Res@1.

-spec root_mean_square_error(
    gleam@iterator:iterator({gleam_zlists@interop:z_list(float()),
                             gleam_zlists@interop:z_list(float())})
) -> float().
root_mean_square_error(Y_hats_with_ys) ->
    {N, S} = begin
        _pipe = Y_hats_with_ys,
        _pipe@1 = gleam@iterator:map(
            _pipe,
            fun(T) ->
                {Y_hat, Y} = T,
                D = euclidean_distance(Y_hat, Y),
                D
                * D
            end
        ),
        gleam@iterator:fold(
            _pipe@1,
            {0, 0.0},
            fun(Acc, X) ->
                {Acc_n, Acc_s} = Acc,
                {Acc_n + 1, Acc_s + X}
            end
        )
    end,
    Avg = case gleam@int:to_float(N) of
        0.0 -> 0.0;
        Gleam@denominator -> S / Gleam@denominator
    end,
    {ok, Res@1} = case gleam@float:square_root(Avg) of
        {ok, Res} -> {ok, Res};
        _try ->
            erlang:error(#{gleam_error => assert,
                           message => <<"Assertion pattern match failed"/utf8>>,
                           value => _try,
                           module => <<"gleam_synapses/model/mathematics"/utf8>>,
                           function => <<"root_mean_square_error"/utf8>>,
                           line => 57})
    end,
    Res@1.

-spec index_of_max_val(gleam_zlists@interop:z_list(float())) -> integer().
index_of_max_val(Ys) ->
    {ok, {Hd@1, Rst@1}} = case begin
        _pipe = gleam_zlists:indices(),
        _pipe@1 = gleam_zlists:zip(_pipe, Ys),
        gleam_zlists:uncons(_pipe@1)
    end of
        {ok, {Hd, Rst}} -> {ok, {Hd, Rst}};
        _try ->
            erlang:error(#{gleam_error => assert,
                           message => <<"Assertion pattern match failed"/utf8>>,
                           value => _try,
                           module => <<"gleam_synapses/model/mathematics"/utf8>>,
                           function => <<"index_of_max_val"/utf8>>,
                           line => 62})
    end,
    _pipe@2 = gleam_zlists:reduce(
        Rst@1,
        Hd@1,
        fun(X, Acc) ->
            {_@1, V} = X,
            {_@2, Acc_v} = Acc,
            case V > Acc_v of
                true ->
                    X;

                false ->
                    Acc
            end
        end
    ),
    gleam@pair:first(_pipe@2).

-spec accuracy(
    gleam@iterator:iterator({gleam_zlists@interop:z_list(float()),
                             gleam_zlists@interop:z_list(float())})
) -> float().
accuracy(Y_hats_with_ys) ->
    {N, S} = begin
        _pipe = Y_hats_with_ys,
        _pipe@1 = gleam@iterator:map(
            _pipe,
            fun(T) ->
                {Y_hat, Y} = T,
                index_of_max_val(Y_hat)
                =:= index_of_max_val(Y)
            end
        ),
        gleam@iterator:fold(
            _pipe@1,
            {0, 0},
            fun(Acc, X) ->
                {Acc_n, Acc_s} = Acc,
                New_s = case X of
                    true ->
                        Acc_s + 1;

                    false ->
                        Acc_s
                end,
                {Acc_n + 1, New_s}
            end
        )
    end,
    case gleam@int:to_float(N) of
        0.0 -> 0.0;
        Gleam@denominator -> gleam@int:to_float(S) / Gleam@denominator
    end.