def ComputeCorr(
Bodies,
direct='',
nbins=250
): #This Computes the correlation function for the bodies in the array Bodies.
X = np.zeros((len(Bodies), 3))
for i in range(len(Bodies)):
X[i] = Bodies[i].position
bins = np.logspace(-5, 2, int(nbins))
corr = two_point(
X, bins
) + 1 #This is where the two point correlation is computed and stored in an array named corr.
DATA = np.array(
[bins[1:], corr]
).T # This array contains the correlation function data as (r,corr) points.
DATA = DATA[~np.any(
np.isnan(DATA),
axis=1)] # Removes nan's because curve_fit doesn't handle them well.
np.savetxt(direct + 'Corr.txt', DATA, fmt='%f')
# a = np.loadtxt('Corr.txt') # To load the data form text
return DATA
def tp_corr(out_count, rbin_N):
path_dir = parent_dir + 'output/'
if os.path.isfile(path_dir + 'particle_' + str(out_count) + '.npy'):
out_data = np.load(path_dir + 'particle_' + str(out_count) + '.npy')
out_info = np.load(path_dir + 'info_' + str(out_count) + '.npy',
allow_pickle=True).item()
rbin = np.logspace(0.5, 2.5, num=rbin_N)
posn = out_data[:, 1:4]
corr = two_point(posn, rbin)
print(np.shape(corr))
print(corr)
rbin = rbin[:-1]
print(np.shape(rbin))
plt.figure()
plt.xscale('log')
plt.yscale('log')
plt.plot(rbin, corr)
plt.title('With expansion: 20000 particles')
plt.xlabel(r'r (in code units)')
plt.ylabel(r'$\xi$(r)')
plt.savefig(parent_dir + 'two_point_corr_' + str(out_count) + '.png')
plt.close()
def ac_astroML(self):
'''from two_point_angular() in astroML/correlation.py'''
from astroML.correlation import two_point, ra_dec_to_xyz, angular_dist_to_euclidean_dist
# 3d project
data = np.asarray(ra_dec_to_xyz(self.gal_ra, self.gal_dec),
order='F').T
data_R = np.asarray(ra_dec_to_xyz(self.ran_ra, self.ran_dec),
order='F').T
# convert spherical bins to cartesian bins
bins = 10**np.linspace(np.log10(1. / 60.), np.log10(6), 16)
bins_transform = angular_dist_to_euclidean_dist(bins)
w = two_point(data,
bins_transform,
method='landy-szalay',
data_R=data_R)
bin_centers = 0.5 * (bins[1:] + bins[:-1])
return bin_centers, w
def find_corr(ponds,random_fraction,bins):
random_points = np.random.rand(np.shape(ponds)[0],np.shape(ponds)[1]) < random_fraction
ponds_coordinates = np.array(np.nonzero(ponds*random_points)).T
corr = two_point(ponds_coordinates, bins)
loc = corr == corr
C = corr[loc]
d = bins[1:][loc]
C = np.hstack([1.,C,0.])
d = np.hstack([0.,d,np.inf])
Cd_interp = interp1d(C,d,kind = 'linear')
l0 = Cd_interp(np.exp(-1))
return_corr = np.hstack([1.,corr,0.])
return_dist = np.hstack([0.,bins[1:],np.inf])
return return_corr,return_dist,l0
N = 500
offset = 60.0
noise = 3.0
BAO = 20.0
for i in xrange(100):
N1 = np.random.randint(N/10.0, N)
N2 = np.random.randint(N/10.0, N)
r1 = (np.random.random(N1)-0.5)*noise* np.random.random()
r2 = BAO + (np.random.random(N2)-0.5)*noise* np.random.random()
x_off = 2*offset*(np.random.random() - 0.5)
y_off = 2*offset*(np.random.random() - 0.5)
z_off = 2*offset*(np.random.random() - 0.5)
theta1 = np.random.random(N1) * np.pi
phi1 = np.random.random(N1) * 2 * np.pi
c1 = np.vstack( (r1*np.sin(theta1)*np.cos(phi1)+x_off, r1*np.sin(theta1)*np.sin(phi1)+y_off, r1*np.cos(theta1)+z_off ))
theta2 = np.random.random(N2) * np.pi
phi2 = np.random.random(N2) * 2 * np.pi
c2 = np.vstack( (r2*np.sin(theta2)*np.cos(phi2)+x_off, r2*np.sin(theta2)*np.sin(phi2)+y_off, r2*np.cos(theta2)+z_off ))
c = np.hstack( (c,c1,c2) )
fig = plt.figure()
ax = fig.add_subplot(111, projection='3d')
np.random.shuffle(c)
ax.scatter(c[0][:], c[1][:], c[2][:])
plt.show()
cor = two_point(c.T, np.linspace(int(BAO)/10.0, int(BAO)*2, int(BAO)*2), method='landy-szalay')
plt.plot(cor)
plt.show()
def two_point_corr(xyz, xyz_rand):
bins = np.linspace(bin_min, bin_max, nbins)
corr = cor.two_point(xyz.T, bins, method='landy-szalay', data_R = xyz_rand.T)
print corr
s_ls = bins[:-1]+(bin_max-bin_min)/(2*nbins)
plt.plot(s_ls, s_ls**2 * corr)
def two_point_corr(xyz):
bins = np.linspace(0, 1, 51)
corr = cor.two_point(xyz.T, bins, method='landy-szalay')
print corr
plt.plot(corr)
def new_bootstrap_two_point_angular(ra_G,dec_G, bins, method='standard',\
ra_R=None,dec_R=None, Nbootstraps=10,\
random_state=None):
"""Angular two-point correlation function
A separate function is needed because angular distances are not
euclidean, and random sampling needs to take into account the
spherical volume element.
Parameters
----------
ra_G, dec_G : array_like
Observed galaxy ra,dec
bins : array_like
bins within which to compute the 2-point correlation.
shape = Nbins + 1
method : string
"standard" or "landy-szalay".
ra_R, dec_R : array_like
Random catlogue of ra,dec
Nbootstraps : int
number of bootstrap resamples
Returns
-------
corr : ndarray
the estimate of the correlation function within each bin
shape = Nbins
dcorr : ndarray
error estimate on dcorr (sample standard deviation of
bootstrap resamples)
bootstraps : ndarray
The full sample of bootstraps used to compute corr and dcorr
"""
data = np.asarray(ra_dec_to_xyz(ra_G, dec_G), order='F').T
n_samples, n_features = data.shape
if random_state is None:
rng= np.random.RandomState()
if ra_R is None or dec_R is None:
print('Creating random sample')
data_R = data.copy()
for i in range(n_features - 1):
rng.shuffle(data_R[:, i])
else:
data_R = np.asarray(ra_dec_to_xyz(ra_R, dec_R), order='F').T
if (data_R.ndim != 2) or (data_R.shape[-1] != n_features):
raise ValueError('data_R must have same n_features as data')
bins = np.asarray(bins)
Nbins = len(bins) - 1
if method not in ['standard', 'landy-szalay']:
raise ValueError("method must be 'standard' or 'landy-szalay'")
if bins.ndim != 1:
raise ValueError("bins must be a 1D array")
if data.ndim == 1:
data = data[:, np.newaxis]
elif data.ndim != 2:
raise ValueError("data should be 1D or 2D")
# convert spherical bins to cartesian bins
bins_transform = angular_dist_to_euclidean_dist(bins)
bootstraps = []
# Bootstrap sample data_R, hold data fixed
#R_samples, R_features = data_R.shape
#for i in range(Nbootstraps):
# # Sample with replacement
# #inds= rng.randint(R_samples, size=R_samples) #np.random.randint
# ind = rng.randint(0, R_samples, R_samples)
# new_R= data_R[ind,:]
# print('WARNING: look in code, is new_R shape correct?')
# bootstraps.append(two_point(data, bins_transform, method=method,
# data_R=new_R, random_state=rng))
# Now, bootstrap sample data, hold data_R
for i in range(Nbootstraps):
print('Computing bootstrap: %d' % (i+1,))
ind = rng.randint(0, n_samples, n_samples)
new_G= data[ind,:]
bootstraps.append(two_point(new_G, bins_transform, method=method,
data_R=data_R, random_state=rng))
bootstraps = np.asarray(bootstraps)
corr = np.mean(bootstraps, 0)
corr_err = np.std(bootstraps, 0, ddof=1)
return corr, corr_err, bootstraps
