øving8

import imagestuff
import numpy as np

def coeff(n, funcvec):
    ret = 0.0
    L = len(funcvec)
    if n == 0:
        for i in xrange(0, L):
            ret += funcvec[i]
        ret /= float(L)
    else:
        for i in xrange(0, L):
            ret += funcvec[i] * (np.sin((n * np.pi * (i + 1)) / L) - np.sin((n * np.pi * i) / L))
        ret *= 2.0/ (n * np.pi)
    return ret

def coscoefficients(funcvec, n):
    ret = np.zeros(n)
    for i in xrange(0,n):
        ret[i] = coeff(i, funcvec)
    return ret

def cosseries(coeffvec, n):
    ret = np.zeros(n)
    for i in xrange(0, n):
        ret[i] = coeffvec[0]
        for j in xrange(1, len(coeffvec)):
            ret[i] += coeffvec[j] * np.cos((j * np.pi * i)/float(len(coeffvec)))
    return ret

def main():
    vec = [7, 1, 11, 2, 9]
    coeffs = (coscoefficients(vec, 10))
    apprseries = cosseries(coeffs, len(vec))
    print 'Vektor: ', vec
    print 'Koeffisienter: ', coeffs
    print 'Rekketiln: ', apprseries
    
main()