diff --git a/lab4/src/algo/compute.rs b/lab4/src/algo/compute.rs
new file mode 100644
index 0000000..a66abc9
--- /dev/null
+++ b/lab4/src/algo/compute.rs
@@ -0,0 +1,17 @@
+fn compute_potential<const Is: usize, const Os: usize>(
+    weights: &[[f64; Is]; Os],
+    input_data: &[f64; Is],
+    potential_data: &mut [f64; Is],
+    output_data: &mut [f64; Is],
+    f: impl Fn(f64) -> f64
+) {
+    for (i, n) in weights.iter().enumerate() {
+        let P = input_data
+            .iter()
+            .zip(n)
+            .map(|(x, w)| x.apply_weight(*w))
+            .sum();
+        potential_data[i] = P;
+        output_data[i] = f(P);
+    };
+}
diff --git a/lab4/src/algo/fix.rs b/lab4/src/algo/fix.rs
new file mode 100644
index 0000000..40465f3
--- /dev/null
+++ b/lab4/src/algo/fix.rs
@@ -0,0 +1,30 @@
+fn calc_error<const Cs: usize, const Ns: usize>(
+    next_errors: &[f64; Ns],
+    weights: &[[f64; Cs]; Ns],
+    current_errors: &mut [f64; Cs]
+) {
+    for i in 0..Cs {
+        current_errors[i] = weights
+            .iter()
+            .enumerate()
+            .map(|(j, ww)| ww[i] * next_errors[j])
+            .sum();
+    }
+}
+
+fn apply_error<const Cs: usize, const Ns: usize>(
+    n: f64,
+    errors: &[f64; Ns],
+    weights: &mut [[f64; Cs]; Ns],
+    current_potentials: &[f64; Cs],
+    next_potentials: &[f64; Cs],
+    f: impl Fn(f64) -> f64,
+    f1: impl Fn(f64) -> f64
+) {
+    for i in 0..Cs {
+        for j in 0..Ns {
+            let dw = n * errors[j] * f1(next_potentials[j]) * f(current_potentials[i]);
+            weights[j][i] += dw;
+        }
+    }
+}
diff --git a/lab4/src/algo/layer.rs b/lab4/src/algo/layer.rs
deleted file mode 100644
index 8c961cc..0000000
--- a/lab4/src/algo/layer.rs
+++ /dev/null
@@ -1,9 +0,0 @@
-pub trait Layer {
-    type InputType;
-    type OutputType;
-
-    fn compute(&self, input_data: &[Self::InputType], output_data: &mut [Self::OutputType]);
-
-    fn input_size(&self) -> usize;
-    fn output_size(&self) -> usize;
-}
diff --git a/lab4/src/algo/layer_impl.rs b/lab4/src/algo/layer_impl.rs
deleted file mode 100644
index 546ba32..0000000
--- a/lab4/src/algo/layer_impl.rs
+++ /dev/null
@@ -1,102 +0,0 @@
-use crate::algo::layer::Layer;
-use crate::algo::layers_union::LayersUnion;
-use std::iter::Sum;
-use std::marker::PhantomData;
-use std::ops::Add;
-
-struct Neuron<const PrevLayerSize: usize> {
-    input_weights: [f64; PrevLayerSize],
-}
-
-pub trait ApplyWeight<Output> {
-    fn apply_weight(&self, w: f64) -> Output;
-}
-
-impl ApplyWeight<f64> for f64 {
-    fn apply_weight(&self, w: f64) -> f64 {
-        return *self * w;
-    }
-}
-
-pub struct LayerImpl<
-    const PrevLayerSize: usize,
-    const CurrentLayerSize: usize,
-    InputType: ApplyWeight<WeightedType>,
-    WeightedType,
-    ActivationType: Sum<WeightedType>,
-    ActivationFunction: Fn(ActivationType) -> OutputType,
-    OutputType,
-> {
-    neurons: [Neuron<PrevLayerSize>; CurrentLayerSize],
-    activation_function: ActivationFunction,
-    __phantom: PhantomData<(InputType, WeightedType, ActivationType, OutputType)>,
-}
-
-impl<
-    const PrevLayerSize: usize,
-    const CurrentLayerSize: usize,
-    InputType: ApplyWeight<WeightedType>,
-    WeightedType,
-    ActivationType: Sum<WeightedType>,
-    ActivationFunction: Fn(ActivationType) -> OutputType,
-    OutputType,
-> Layer
-    for LayerImpl<
-        PrevLayerSize,
-        CurrentLayerSize,
-        InputType,
-        WeightedType,
-        ActivationType,
-        ActivationFunction,
-        OutputType,
-    >
-{
-    type InputType = InputType;
-    type OutputType = OutputType;
-
-    fn compute(&self, input_data: &[InputType], output_data: &mut [OutputType]) {
-        for (i, n) in self.neurons.iter().enumerate() {
-            let P = input_data
-                .iter()
-                .zip(n.input_weights)
-                .map(|(x, w)| x.apply_weight(w))
-                .sum();
-            output_data[i] = (self.activation_function)(P);
-        }
-    }
-
-    fn input_size(&self) -> usize {
-        return PrevLayerSize;
-    }
-
-    fn output_size(&self) -> usize {
-        return CurrentLayerSize;
-    }
-}
-
-impl<
-    const PrevPrevLayerSize: usize,
-    const PrevLayerSize: usize,
-    PrevLayerInputType: ApplyWeight<PrevLayerWeightedType>,
-    PrevLayerWeightedType,
-    PrevLayerActivationType: Sum<PrevLayerWeightedType>,
-    PrevLayerActivationFunction: Fn(PrevLayerActivationType) -> PrevLayerOutputType,
-    PrevLayerOutputType,
-    CurrentLayer: Layer<InputType = PrevLayerOutputType>,
-> Add<CurrentLayer>
-    for LayerImpl<
-        PrevPrevLayerSize,
-        PrevLayerSize,
-        PrevLayerInputType,
-        PrevLayerWeightedType,
-        PrevLayerActivationType,
-        PrevLayerActivationFunction,
-        PrevLayerOutputType,
-    >
-{
-    type Output = LayersUnion<Self, CurrentLayer>;
-
-    fn add(self, rhs: CurrentLayer) -> Self::Output {
-        return LayersUnion::join(self, rhs);
-    }
-}
diff --git a/lab4/src/algo/layers_union.rs b/lab4/src/algo/layers_union.rs
deleted file mode 100644
index b619f6a..0000000
--- a/lab4/src/algo/layers_union.rs
+++ /dev/null
@@ -1,67 +0,0 @@
-use crate::algo::layer::Layer;
-use std::ops::Add;
-
-pub struct LayersUnion<
-    PrevLayer: Layer,
-    CurrentLayer: Layer<InputType = PrevLayer::OutputType>,
-> {
-    prev_layer: PrevLayer,
-    current_layer: CurrentLayer,
-}
-
-impl<PrevLayer: Layer, CurrentLayer: Layer<InputType = PrevLayer::OutputType>>
-    LayersUnion<PrevLayer, CurrentLayer>
-{
-    pub fn join(l1: PrevLayer, l2: CurrentLayer) -> Self {
-        assert_eq!(l1.output_size(), l2.input_size());
-        return Self {
-            prev_layer: l1,
-            current_layer: l2,
-        };
-    }
-}
-
-impl<PrevLayer: Layer, CurrentLayer: Layer<InputType = PrevLayer::OutputType>> Layer
-    for LayersUnion<PrevLayer, CurrentLayer>
-{
-    type InputType = PrevLayer::InputType;
-    type OutputType = CurrentLayer::OutputType;
-
-    fn compute(&self, input_data: &[Self::InputType], output_data: &mut [Self::OutputType]) {
-        let mut intermediate_data_s =
-            vec![0u8; self.prev_layer.output_size() * size_of::<PrevLayer::OutputType>()]
-                .into_boxed_slice();
-
-        let intermediate_data;
-        unsafe {
-            intermediate_data = std::slice::from_raw_parts_mut(
-                intermediate_data_s.as_mut_ptr().cast::<PrevLayer::OutputType>(),
-                self.prev_layer.output_size(),
-            )
-        }
-        self.prev_layer.compute(input_data, intermediate_data);
-        self.current_layer.compute(intermediate_data, output_data);
-    }
-
-    fn input_size(&self) -> usize {
-        return self.prev_layer.input_size();
-    }
-
-    fn output_size(&self) -> usize {
-        return self.current_layer.output_size();
-    }
-}
-
-impl<
-    PrevLayer: Layer,
-    CurrentLayer: Layer<InputType = PrevLayer::OutputType>,
-    NextLayer: Layer<InputType = CurrentLayer::OutputType>,
-> Add<NextLayer>
-    for LayersUnion<PrevLayer, CurrentLayer>
-{
-    type Output = LayersUnion<Self, NextLayer>;
-
-    fn add(self, rhs: NextLayer) -> Self::Output {
-        return LayersUnion::join(self, rhs);
-    }
-}
diff --git a/lab4/src/algo/mod.rs b/lab4/src/algo/mod.rs
index 5f0c50a..0a290fc 100644
--- a/lab4/src/algo/mod.rs
+++ b/lab4/src/algo/mod.rs
@@ -1,3 +1,2 @@
-mod layer;
-mod layers_union;
-mod layer_impl;
+mod compute;
+mod fix;