# Author: Alex Gezerlis

# Numerical Methods in Physics with Python (CUP, 2020)

from math import pi

import numpy as np

def f(x):

return np.exp(np.sin(2*x))

def generatedata(n,f):

dataxs = 2*pi*np.arange(n)/n

datays = f(dataxs)

return dataxs, datays

def computeparams(dataxs,datays):

n = dataxs.size

m = n//2

aparams = np.zeros(m+1)

bparams = np.zeros(m-1)

for k in range(m+1):

aparams[k] = [email protected](k*dataxs)/m

for k in range(1,m):

bparams[k-1] = [email protected](k*dataxs)/m

return aparams, bparams

def triginterp(aparams,bparams,x):

n = aparams.size + bparams.size

m = n//2

val = 0.5*(aparams[0] + aparams[-1]*np.cos(m*x))

for k in range(1,m):

val += aparams[k]*np.cos(k*x)

val += bparams[k-1]*np.sin(k*x)

return val

if __name__ == '__main__':

dataxs, datays = generatedata(8, f)

aparams, bparams = computeparams(dataxs, datays)

x = 0.3; pofx = triginterp(aparams, bparams, x)

print(x,pofx)