diff --git a/.prettierignore b/.prettierignore
index 1b763b1..c2c86c1 100644
--- a/.prettierignore
+++ b/.prettierignore
@@ -1 +1,2 @@
 CHANGELOG.md
+benchmark/old
diff --git a/benchmark/benchmarkLinePlot.js b/benchmark/benchmarkLinePlot.js
index 175b042..ce9d1cc 100644
--- a/benchmark/benchmarkLinePlot.js
+++ b/benchmark/benchmarkLinePlot.js
@@ -3,7 +3,7 @@ import { xSequentialFillFromStep } from 'ml-spectra-processing';
 
 import { SparseMatrix } from '../src/index.js';
 
-import { SparseMatrix as SparseMatrixOld } from './class/SparseMatrixOld.js';
+import { SparseMatrix as SparseMatrixOld } from './old/index.js';
 import { randomMatrix } from './utils/randomMatrix.js';
 
 const density = 0.02; // Fixed density for this comparison;
diff --git a/benchmark/densityDecreaseWhenSizeIncrease.js b/benchmark/densityDecreaseWhenSizeIncrease.js
index 8ed6101..1fbf6aa 100644
--- a/benchmark/densityDecreaseWhenSizeIncrease.js
+++ b/benchmark/densityDecreaseWhenSizeIncrease.js
@@ -3,7 +3,7 @@ import { bench, do_not_optimize, group, run } from 'mitata';
 // import { Matrix } from 'ml-matrix';
 import { SparseMatrix } from '../src/index.js';
 
-import { SparseMatrix as SparseMatrixOld } from './class/SparseMatrixOld.js';
+import { SparseMatrix as SparseMatrixOld } from './old/index.js';
 import { randomMatrix } from './utils/randomMatrix.js';
 
 const sizes = [8, 16, 32, 256, 512, 1024];
diff --git a/benchmark/class/SparseMatrixOld.js b/benchmark/old/index.js
similarity index 100%
rename from benchmark/class/SparseMatrixOld.js
rename to benchmark/old/index.js
diff --git a/eslint.config.js b/eslint.config.js
index 3ca4395..629ad2b 100644
--- a/eslint.config.js
+++ b/eslint.config.js
@@ -1,7 +1,7 @@
 import { defineConfig, globalIgnores } from 'eslint/config';
 import ts from 'eslint-config-cheminfo-typescript/base';
 
-export default defineConfig(globalIgnores(['benchmark/class/*', 'lib']), ts, {
+export default defineConfig(globalIgnores(['benchmark/old', 'lib']), ts, {
   files: ['benchmark/**'],
   rules: {
     camelcase: 'off',