diff --git a/example.ipynb b/example.ipynb
new file mode 100644
index 0000000..dc235e1
--- /dev/null
+++ b/example.ipynb
@@ -0,0 +1,47 @@
+{
+ "cells": [
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# prerequisites: KrylovKit, TensorOperations, LinearAlgebra, CUDA#tb/cutensor (for GPU mode)\n",
+    "\n",
+    "include(\"CPU.jl\") # using CPU mode\n",
+    "T = Float32\n",
+    "\n",
+    "V_test(r2::T)::T =\n",
+    "    -4 * exp(-r2 / 4)\n",
+    "\n",
+    "d = 3\n",
+    "n = 3\n",
+    "N = 6\n",
+    "L::T = 12.0\n",
+    "mu::T = 0.5\n",
+    "n_imag = 1\n",
+    "\n",
+    "H = HOperator{T}(V_test, 3, 3, N, L, 0.5f0, 1)\n",
+    "@time evals, evecs, info = eig(H, 5)\n",
+    "print(info.numops, \" operations : \")\n",
+    "println(evals)"
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Julia 1.8.5",
+   "language": "julia",
+   "name": "julia-1.8"
+  },
+  "language_info": {
+   "file_extension": ".jl",
+   "mimetype": "application/julia",
+   "name": "julia",
+   "version": "1.8.5"
+  },
+  "orig_nbformat": 4
+ },
+ "nbformat": 4,
+ "nbformat_minor": 2
+}
diff --git a/tester.ipynb b/tester.ipynb
deleted file mode 100644
index 2878b6c..0000000
--- a/tester.ipynb
+++ /dev/null
@@ -1,70 +0,0 @@
-{
- "cells": [
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
-   "source": [
-    "# ./En.run -d 3 -n 3 -e 5 -c eps=0 -c pot=v_gauss,v0=-4,r=2 -N 6 -L 5:14 -c n_imag=1\n",
-    "\n",
-    "include(\"CPU.jl\")\n",
-    "\n",
-    "T=Float32\n",
-    "\n",
-    "function V_test(r2::T)::T\n",
-    "    return -4*exp(-r2/4)\n",
-    "end\n",
-    "\n",
-    "N=6\n",
-    "for L::T in 5.0:14.0\n",
-    "    H=HOperator{T}(V_test,3,3,N,L,0.5f0,1)\n",
-    "    @time evals,evecs,info=eig(H,5)\n",
-    "    print(info.numops,\" operations : \")\n",
-    "    println(evals)\n",
-    "end"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
-   "source": [
-    "# ./En.run -d 3 -n 2 -e 5 -c eps=0 -c pot=v_gauss,v0=-4,r=2 -N 32 -L 5:14 -c n_imag=0\n",
-    "\n",
-    "include(\"CPU.jl\")\n",
-    "\n",
-    "T=Float64\n",
-    "\n",
-    "function V_test(r2::T)::T\n",
-    "    return -4*exp(-r2/4)\n",
-    "end\n",
-    "\n",
-    "N=32\n",
-    "for L::T in 5.0:14.0\n",
-    "    H=HOperator{T}(V_test,3,2,N,L)\n",
-    "    @time evals,evecs,info=eig(H,5)\n",
-    "    print(info.numops,\" operations : \")\n",
-    "    println(evals)\n",
-    "end"
-   ]
-  }
- ],
- "metadata": {
-  "kernelspec": {
-   "display_name": "Julia 1.8.5",
-   "language": "julia",
-   "name": "julia-1.8"
-  },
-  "language_info": {
-   "file_extension": ".jl",
-   "mimetype": "application/julia",
-   "name": "julia",
-   "version": "1.8.5"
-  },
-  "orig_nbformat": 4
- },
- "nbformat": 4,
- "nbformat_minor": 2
-}
diff --git a/tester.jl b/tester.jl
deleted file mode 100644
index 95f2069..0000000
--- a/tester.jl
+++ /dev/null
@@ -1,43 +0,0 @@
-# ./En.run -d 3 -n 3 -e 5 -c eps=0 -c pot=v_gauss,v0=-4,r=2 -N 6 -L 5:14 -c n_imag=1
-
-using CUDA
-
-GPU_mode = !("CPU" in ARGS) && CUDA.functional() && CUDA.has_cuda() && CUDA.has_cuda_gpu()
-
-println("Running with ",Threads.nthreads()," thread(s)")
-
-if GPU_mode
-    include("GPU.jl")
-    println("Available GPUs:")
-    print("    ")
-    println.(name.(devices()))
-else
-    include("CPU.jl")
-end
-
-T=Float32
-
-function V_zero(r2::T)::T
-    return 0.0
-end
-
-function V_test(r2::T)::T
-    return -4*exp(-r2/4)
-end
-
-N=6
-n_image=1
-μ=0.5
-
-levels=5
-
-for L::T in 5.0:14.0
-    H=HOperator{T}(V_test,3,3,N,L,convert(T,μ),n_image)
-    if GPU_mode
-        CUDA.@time evals,evecs,info=eig(H,levels)
-    else
-        @time evals,evecs,info=eig(H,levels)
-    end
-    print(info.numops," operations : ")
-    println(evals)
-end
\ No newline at end of file