def compare_eigen_methods():
""" timing of different eigensolver methods"""
import scipy.linalg as linalg
print '\n *** diagonalize a real symmetric band matrix by different methods ***\n'
mt=mytimer.create(10)
try:
N=float(sys.argv[1])
S=float(sys.argv[2])
except:
sys.exit('supply N S (command line arguments): matrix dimension N and and number of super-diagonals S ')
np.random.seed(1)
a=np.random.random((N,N))
ab=GMatrix(np.random.random((S+1,N)),storage='upper_banded')
mt[0].start('lapack symmetric upper banded')
print ab.store+'\n',ab.eigvals()[:5]
mt[0].stop()
a=ab.restore('full')
mt[1].start('lapack symmetric full')
print a.store+'\n',a.eigvals()[:5]
mt[1].stop()
print 'lingalg'
mt[2].start('linalg general')
print np.sort(linalg.eigvals(a.m).real)[:5]
mt[2].stop()
mytimer.table()
#! /usr/bin/env python
# inverse iteration
import sys
import numpy as np
from math import *
import scipy.linalg as la
import mytimer as mt
# get timer
t=mt.create(10)
eps_machine=1.e-14 # just guessing...
# numpy print style
np.set_printoptions(precision=12,suppress=True,linewidth=132)
# parameters
M=1
Klu=20
Kpower=1
# input
try: N=int(sys.argv[1])
except: N=100
try: eguess=float(sys.argv[2])
except: eguess=5.
if M>N: exit('M>N')
