88 lines
2.1 KiB
Plaintext
88 lines
2.1 KiB
Plaintext
{
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"cells": [
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": [
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"from itertools import chain\n",
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"import numpy as np\n",
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"import math\n",
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"from scipy import sparse\n",
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"from scipy.sparse.linalg import eigsh\n",
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"\n",
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"#sample potential\n",
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"def V_gauss(dr_sqr):\n",
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" return -4*math.exp(-dr_sqr/4)\n",
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"\n",
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"n=3 # no of particles\n",
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"L=14\n",
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"N=6 # no of lattice points\n",
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"mu=1/2 # reduced mass\n",
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"\n",
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"DOF=(n-1)*3 # degrees of freedom after excluding CM\n",
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"\n",
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"s=np.arange(N**DOF) # matrix index\n",
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"\n",
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"# k index for each particle and each dimension\n",
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"k=np.empty((n-1,3),dtype=np.dtype)\n",
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"for dof in range(DOF):\n",
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" k[dof//3,dof%3]=(s%N**(DOF-dof))//N**(DOF-1-dof)-N//2\n",
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"\n",
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"x=k*(L/N) # x coordinate from k index\n",
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"\n",
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"# adding up all non-local interactions\n",
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"V_local=np.zeros(N**DOF)\n",
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"\n",
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"# 2-body interactions\n",
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"V2=np.vectorize(V_gauss)\n",
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"dxs=chain((x[i,:] for i in range(n-1)), (x[i,:]-x[j,:] for (i,j) in np.ndindex((n-1,n-1)) if i<j)) # with last particle + with each other\n",
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"for dx in dxs:\n",
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" dr_sqr=np.sum(dx*dx)\n",
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" V_local+=V2(dr_sqr)"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": [
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"filename = \"temp/V_vals.dat\"\n",
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"\n",
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"with open(filename, 'br') as f:\n",
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" buffer = f.read()\n",
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"\n",
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"V_julia = np.frombuffer(buffer, dtype=np.float32)\n",
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"\n",
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"abs_diff = np.abs(V_local-V_julia)\n",
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"s = np.mean(abs_diff)\n",
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"print(s)"
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]
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}
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],
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"metadata": {
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"kernelspec": {
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"display_name": "base",
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"language": "python",
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"name": "python3"
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},
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"language_info": {
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"codemirror_mode": {
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"name": "ipython",
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"version": 3
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},
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"file_extension": ".py",
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"mimetype": "text/x-python",
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"name": "python",
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"nbconvert_exporter": "python",
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"pygments_lexer": "ipython3",
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"version": "3.9.13"
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},
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"orig_nbformat": 4
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},
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"nbformat": 4,
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"nbformat_minor": 2
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}
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