perceptron-viewer/resources/js/components/PerceptronDecisionGraph.vue

<script setup lang="ts">
import type {
    ChartDataset,
    ChartTypeRegistry,
    BubbleDataPoint,
    Point,
} from 'chart.js';
import { computed } from 'vue';
import { Chart } from 'vue-chartjs';
import { colors } from '@/types/graphs';
import type { Iteration } from '@/types/perceptron';

const props = defineProps<{
    cleanedDataset: { label: number; data: { x: number; y: number }[] }[];
    iterations: Iteration[];
    activationFunction: (x: number) => number;
}>();

const farLeftDataPointX = computed(() => {
    if (props.cleanedDataset.length === 0) {
        return 0;
    }
    const minX = Math.min(...props.cleanedDataset.flatMap((d) => d.data.map((point) => point.x)));
    return minX;
});
const farRightDataPointX = computed(() => {
    if (props.cleanedDataset.length === 0) {
        return 0;
    }
    const maxX = Math.max(...props.cleanedDataset.flatMap((d) => d.data.map((point) => point.x)));
    return maxX;
});

function getPerceptronDecisionBoundaryDataset(
    networkWeights: number[][][],
    activationFunction: (x: number) => number = (x) => x,
): ChartDataset<
    keyof ChartTypeRegistry,
    number | Point | [number, number] | BubbleDataPoint | null
> {
    const label = 'Ligne de décision du Perceptron';
    console.log('Calculating decision boundary with weights:', networkWeights);

    if (
        networkWeights.length == 1 &&
        networkWeights[0].length == 1 &&
        networkWeights[0][0].length == 3
    ) { // Unique, 3 weights perceptron
        const perceptronWeights = networkWeights[0][0]; // We take the unique

        function perceptronLine(x: number): number {
            // w0 + w1*x + w2*y = 0 => y = -(w1/w2)*x - w0/w2
            const w2 = perceptronWeights[2] == 0 ? 1e-6 : perceptronWeights[2]; // Avoid division by zero
            return -(perceptronWeights[1] / w2) * x - perceptronWeights[0] / w2;
        }

        // Simple line
        return {
            type: 'line',
            label: label,
            data: [
                {
                    x: farLeftDataPointX.value - 1,
                    y: perceptronLine(farLeftDataPointX.value - 1),
                },
                {
                    x: farRightDataPointX.value + 1,
                    y: perceptronLine(farRightDataPointX.value + 1),
                },
            ],
            borderColor: '#FFF',
            borderWidth: 2,
            pointRadius: 0,
        };
    } else {
        function forward(x1: number, x2: number): number {
            let activations: number[] = [x1, x2];

            for (const layer of networkWeights) {
                const nextActivations: number[] = [];

                for (const neuron of layer) {
                    const bias = neuron[0];
                    const weights = neuron.slice(1);

                    let sum = bias;

                    for (let i = 0; i < weights.length; i++) {
                        sum += weights[i] * activations[i];
                    }

                    const activated = activationFunction(sum);

                    nextActivations.push(activated);
                }

                activations = nextActivations;
            }

            return activations[0]; // on suppose sortie unique
        }

        // -------- 2️⃣ Échantillonnage grille --------
        const decisionBoundary: Point[] = [];
        const min = -2;
        const max = 2;
        const step = 0.03;
        const epsilon = 0.01;

        for (let x = min; x <= max; x += step) {
            for (let y = min; y <= max; y += step) {
                const value = forward(x, y);

                if (Math.abs(value) < epsilon) {
                    decisionBoundary.push({ x, y });
                }
            }
        }

        // -------- 3️⃣ Dataset ChartJS --------
        return {
            type: 'scatter',
            label: label,
            data: decisionBoundary,
            backgroundColor: '#FFFFFF',
            pointRadius: 1,
        };
    }
}
</script>

<template>
    <Chart
        v-if="props.cleanedDataset.length > 0 || props.iterations.length > 0"
        class="flex"
        :options="{
            responsive: true,
            maintainAspectRatio: true,
            plugins: {
                legend: {
                    position: 'top',
                },
                title: {
                    display: true,
                    text: 'Ligne de décision du Perceptron',
                },
            },
            layout: {
                padding: {
                    left: 10,
                    right: 10,
                    top: 10,
                    bottom: 10,
                },
            },
            scales: {
                x: {
                    type: 'linear',
                    position: 'bottom',
                },
                y: {
                    type: 'linear',
                    position: 'left',
                },
            },
        }"
        :data="{
            datasets: [
                // Points from the dataset
                ...props.cleanedDataset.map((dataset, index) => ({
                    type: 'scatter',
                    label: `Label ${dataset.label}`,
                    data: dataset.data,
                    backgroundColor:
                        colors[index] || '#AAA',
                })),

                // Perceptron decision boundary
                getPerceptronDecisionBoundaryDataset(
                    props.iterations.length > 0
                        ? props.iterations[props.iterations.length - 1].weights
                        : [[[0, 0, 0]]],
                    props.activationFunction,
                ),
            ],
        }"
    />
</template>