Update README.md

Author: nikzarch

lab3/README.md

@@ -1 +1,95 @@
-lab3
+# Completed by
+Зонов Николай
+ - - -
+# Lab 3
+
+Запуск
+
+```bash
+./lab3.escript --linear --lagrange --newton --gauss --step 0.1 -n 4
+```
+--linear, --lagrange, --newton, --gauss — включение соответствующих методов.
+
+--step S — шаг генерации промежуточных точек (по умолчанию 0.5).
+
+# Ключевые моменты реализации
+
+## Точка входа
+```erlang
+-record(state, {
+  methods = [],   % [linear,lagrange,newton,gauss]
+  step    = 0.5,
+  n       = 4
+}).
+
+main(Args) ->
+  State0 = parse_args(Args, #state{}),
+  Methods =
+    case State0#state.methods of
+      [] -> [linear];
+      Ms -> lists:usort(Ms)
+    end,
+  State = State0#state{methods = Methods},
+
+  PrinterPid   = spawn(fun() -> printer_loop() end),
+  GeneratorPid = spawn(fun() -> generator_loop(State#state.step) end),
+  MethodPids   = start_methods(State, GeneratorPid, PrinterPid),
+
+  GeneratorPid ! {methods, MethodPids},
+  input_loop(State, MethodPids, GeneratorPid, []),
+
+  receive after 1000  -> ok end,
+
+  GeneratorPid ! eof,
+  lists:foreach(fun(P) -> P ! eof end, MethodPids),
+  PrinterPid ! eof,
+  ok.
+```
+## Цикл для ввода
+```erlang
+input_loop(State, MethodPids, GenPid, Points) ->
+  case io:get_line("") of
+    eof -> ok;
+    Line ->
+      case parse_point(Line) of
+        {ok, {X, Y}} ->
+          NewPoints0 = Points ++ [{X, Y}],
+          NewPoints = lists:sort(fun({A,_},{B,_}) -> A =< B end, NewPoints0),
+          lists:foreach(fun(Pid) -> Pid ! {window, NewPoints} end, MethodPids),
+          input_loop(State, MethodPids, GenPid, NewPoints);
+        error -> input_loop(State, MethodPids, GenPid, Points)
+      end
+  end.
+
+```
+## Интерполяции всякие
+```erlang
+compute_linear(_X, [])  -> undefined;
+compute_linear(_X, [_]) -> undefined;
+compute_linear(X, Points) ->
+  case find_segment(X, Points) of
+    none -> undefined;
+    {{X1,Y1},{X2,Y2}} ->
+      case X2 =:= X1 of
+        true  -> Y1;
+        false ->
+          T = (X - X1) / (X2 - X1),
+          Y1 + T * (Y2 - Y1)
+      end
+  end.
+
+compute_lagrange(_X, [])  -> undefined;
+compute_lagrange(_X, [{_,Y}]) -> Y;
+compute_lagrange(X, Points) ->
+  Indexed = index_points(Points, 1),
+  lists:sum(
+    [ Yi * lagrange_basis(I, X, Points, Indexed)
+      || {I,{_Xi,Yi}} <- Indexed ]).
+
+compute_newton(_X, [])      -> undefined;
+compute_newton(_X, [{_,Y}]) -> Y;
+compute_newton(X, Points) ->
+  Coefs = newton_divided_diffs(Points),
+  newton_eval(X, Points, Coefs).
+
+```