# Going from MEP to ASE-NEB

Good afternoon everyone,

I’m working on a nudged elastic band project. Our team previously used MEP tools to plot the pathway. We could set our boundaries and Import energies from a .txt file. Unfortunately, the author is no longer maintaining the project and referred us to ASE. From my reading, I’m unable to resolve if ASE-NEB supports our needs. I’ve attached a copy of the python script we use for MEP. If anyone could help translate this to ASE that would be wonderful.

``````from mep.path import Path
from mep.neb import NEB
from mep.models import LEPS
from collections import deque
import numpy as np
from scipy import optimize
from tas_class import *
import matplotlib.pyplot as plt

# finds the minimum energy pathway
# requires python3 with TASMANIAN and mep to run (both available through pip)

# boundaries for each variable for SLSQP optimization
bnds = ((-20,200),(-100,100))
#tbnds = ((0.6,4.0),(60,180))

# number of images for neb calculations
nimage = 50

# set starting point x0 and end point x1
tassurf = TasSurf()
x0 = optimize.minimize(tassurf.grideval,[0, 0], method='SLSQP',bounds=bnds).x # minima one
x1 = optimize.minimize(tassurf.grideval,[180, 0], method='SLSQP',bounds=bnds).x # minima two
#x0 = [0, 70]
#x1 = [180, 70]
print(x0)
print(x1)

path = Path.from_linear_end_points(x0, x1, nimage, 3)  # and k=1
neb =NEB(tassurf, path) # initialize NEB
history = neb.run(verbose=True, n_steps=200) # run
hislen=len(history.history)
print(hislen)
x=[]
y=[]
fp = open('neb_history.txt','w')
for i in range(hislen):
j=i+1
#fp.write('step %d\n' % j)
for hisarr in history.history[i]:
for hishisarr in hisarr:
for point in hishisarr:
fp.write('%.8f    ' % point)
fp.write('\n')
x.append(hisarr[:,0])
y.append(hisarr[:,1])
fp.write('\n')
plt.scatter(x,y)
plt.xlim(-20,200)
plt.ylim(-100,100)
#plt.show()
filename = f'images/frame_{i}.png'
plt.savefig(filename, dpi=96)
plt.close()
x=[]
y=[]
fp.close()

type or paste code here
``````