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Moved mctp2rfc and mc2rfc to markov.py, added CycleMatrix to objects.py

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master
Per A Brodtkorb 8 years ago
parent 3472a720e1
commit f7754c2402
4 changed files with 285 additions and 454 deletions
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19
wafo/markov.py
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@ -211,23 +211,14 @@ def nt2cmat(nt, kind=1):
if kind == 1:
I = np.r_[0:n - 1]
J = np.r_[1:n]
c = nt[I + 1][:,
J - 1] - nt[I][:,
J - 1] - nt[I + 1][:,
J] + nt[I][:,
J]
c = nt[I + 1][:, J - 1] - nt[I][:, J - 1] - nt[I + 1][:, J] + nt[I][:, J]
c2 = np.vstack((c, np.zeros((n - 1))))
cmat = np.hstack((np.zeros((n, 1)), c2))
elif kind == 11: # same as def=1 but using for-loop
cmat = np.zeros((n, n))
j = np.r_[1:n]
for i in range(n - 1):
cmat[i,
j] = nt[i + 1,
j - 1] - nt[i,
j - 1] - nt[i + 1,
j] + nt[i,
j]
cmat[i, j] = nt[i + 1, j - 1] - nt[i, j - 1] - nt[i + 1, j] + nt[i, j]
else:
_raise_kind_error(kind)
return cmat
@ -894,7 +885,7 @@ def cmatplot(cmat, ux=None, uy=None, method=1, clevels=None):
plt.xlabel('min')
plt.ylabel('Max')
# view(-37.5-90,30);
#v = axis;
# v = axis;
# plt.axis([min(ux) max(ux) min(uy) max(uy) v[5:6]]);
elif method == 2: # surf
F = np.flipud(F.T) # Vrid cykelmatrisen for att plotta rett
@ -902,7 +893,7 @@ def cmatplot(cmat, ux=None, uy=None, method=1, clevels=None):
plt.xlabel('min')
plt.ylabel('Max')
# view(-37.5-90,30);
#v = axis;
# v = axis;
# plt.axis([min(ux) max(ux) min(uy) max(uy) v(5:6)]);
# elseif method == 3 # pcolor
# F = flipud(F');
@ -1195,7 +1186,7 @@ def arfm2mctp(Frfc):
F = np.zeros((n, n))
EYE = np.eye((n, n))
#fprintf(1,'Calculating row ');
# fprintf(1,'Calculating row ');
for k in range(n - 1): # k = subdiagonal
# fprintf(1,'-%1d',i);

455
wafo/misc.py
Unescape Escape View File

@ -11,7 +11,7 @@ from numpy import (
amax, logical_and, arange, linspace, atleast_1d,
asarray, ceil, floor, frexp, hypot,
sqrt, arctan2, sin, cos, exp, log, log1p, mod, diff,
inf, pi, interp, isscalar, zeros, ones, linalg,
inf, pi, interp, isscalar, zeros, ones,
sign, unique, hstack, vstack, nonzero, where, extract)
from scipy.special import gammaln
from scipy.integrate import trapz, simps
@ -1185,432 +1185,6 @@ def findrfc(tp, h=0.0, method='clib'):
return np.sort(ind[:ix]) + t_start
def _raise_kind_error(kind):
if kind in (-1, 0):
raise NotImplementedError('kind = {} not yet implemented'.format(kind))
else:
raise ValueError('kind = {}: not a valid value of kind'.format(kind))
def nt2cmat(nt, kind=1):
"""
Return cycle matrix from a counting distribution.
Parameters
----------
NT: 2D array
Counting distribution. [nxn]
kind = 1: causes peaks to be projected upwards and troughs
downwards to the closest discrete level (default).
= 0: causes peaks and troughs to be projected to
the closest discrete level.
= -1: causes peaks to be projected downwards and the
troughs upwards to the closest discrete level.
Returns
-------
cmat = Cycle matrix. [nxn]
Example
--------
>>> import numpy as np
>>> cmat0 = np.round(np.triu(np.random.rand(4, 4), 1)*10)
>>> cmat0 = np.array([[ 0., 5., 6., 9.],
... [ 0., 0., 1., 7.],
... [ 0., 0., 0., 4.],
... [ 0., 0., 0., 0.]])
>>> nt = cmat2nt(cmat0)
>>> np.allclose(nt,
... [[ 0., 0., 0., 0.],
... [ 20., 15., 9., 0.],
... [ 28., 23., 16., 0.],
... [ 32., 27., 20., 0.]])
True
>>> cmat = nt2cmat(nt)
>>> np.allclose(cmat, [[ 0., 5., 6., 9.],
... [ 0., 0., 1., 7.],
... [ 0., 0., 0., 4.],
... [ 0., 0., 0., 0.]])
True
See also
--------
cmat2nt
"""
n = len(nt) # Number of discrete levels
if kind == 1:
I = np.r_[0:n - 1]
J = np.r_[1:n]
c = nt[I+1][:, J-1] - nt[I][:, J-1] - nt[I+1][:, J] + nt[I][:, J]
c2 = np.vstack((c, np.zeros((n - 1))))
cmat = np.hstack((np.zeros((n, 1)), c2))
elif kind == 11: # same as def=1 but using for-loop
cmat = np.zeros((n, n))
j = np.r_[1:n]
for i in range(n - 1):
cmat[i, j] = nt[i+1, j-1] - nt[i, j-1] - nt[i+1, j] + nt[i, j]
else:
_raise_kind_error(kind)
return cmat
def cmat2nt(cmat, kind=1):
"""
CMAT2NT Calculates a counting distribution from a cycle matrix.
Parameters
----------
cmat = Cycle matrix. [nxn]
kind = 1: causes peaks to be projected upwards and troughs
downwards to the closest discrete level (default).
= 0: causes peaks and troughs to be projected to
the closest discrete level.
= -1: causes peaks to be projected downwards and the
troughs upwards to the closest discrete level.
Returns
-------
NT: n x n array
Counting distribution.
Example
-------
>>> import numpy as np
>>> cmat0 = np.round(np.triu(np.random.rand(4, 4), 1)*10)
>>> cmat0 = np.array([[ 0., 5., 6., 9.],
... [ 0., 0., 1., 7.],
... [ 0., 0., 0., 4.],
... [ 0., 0., 0., 0.]])
>>> nt = cmat2nt(cmat0, kind=11)
>>> np.allclose(nt,
... [[ 0., 0., 0., 0.],
... [ 20., 15., 9., 0.],
... [ 28., 23., 16., 0.],
... [ 32., 27., 20., 0.]])
True
>>> cmat = nt2cmat(nt, kind=11)
>>> np.allclose(cmat, [[ 0., 5., 6., 9.],
... [ 0., 0., 1., 7.],
... [ 0., 0., 0., 4.],
... [ 0., 0., 0., 0.]])
True
See also
--------
nt2cmat
"""
n = len(cmat) # Number of discrete levels
nt = zeros((n, n))
if kind == 1:
csum = np.cumsum
flip = np.fliplr
nt[1:n, :n - 1] = flip(csum(flip(csum(cmat[:-1, 1:], axis=0)), axis=1))
elif kind == 11: # same as def=1 but using for-loop
# j = np.r_[1:n]
for i in range(1, n):
for j in range(n - 1):
nt[i, j] = np.sum(cmat[:i, j + 1:n])
else:
_raise_kind_error(kind)
return nt
def mctp2tc(f_Mm, utc, param, f_mM=None):
"""
MCTP2TC Calculates frequencies for the upcrossing troughs and crests
using Markov chain of turning points.
Parameters
----------
f_Mm = the frequency matrix for the Max2min cycles,
utc = the reference level,
param = a vector defining the discretization used to compute f_Mm,
note that f_mM has to be computed on the same grid as f_mM.
f_mM = the frequency matrix for the min2Max cycles.
Returns
-------
f_tc = the matrix with frequences of upcrossing troughs and crests,
Example
-------
>>> fmM = np.array([[ 0.0183, 0.0160, 0.0002, 0.0000, 0],
... [0.0178, 0.5405, 0.0952, 0, 0],
... [0.0002, 0.0813, 0, 0, 0],
... [0.0000, 0, 0, 0, 0],
... [ 0, 0, 0, 0, 0]])
>>> param = (-1, 1, len(fmM))
>>> utc = 0
>>> f_tc = mctp2tc(fmM, utc, param)
>>> np.allclose(f_tc,
... [[ 0.0, 1.59878359e-02, -1.87345256e-04, 0.0, 0.0],
... [ 0.0, 5.40312726e-01, 3.86782958e-04, 0.0, 0.0],
... [ 0.0, 0.0, 0.0, 0.0, 0.0],
... [ 0.0, 0.0, 0.0, 0.0, 0.0],
... [ 0.0, 0.0, 0.0, 0.0, 0.0]])
True
"""
def _check_ntc(ntc, n):
if ntc > n - 1:
raise IndexError('index for mean-level out of range, stop')
def _check_discretization(param, ntc):
if not (1 < ntc < param[2]):
raise ValueError('the reference level out of range, stop')
def _normalize_rows(arr):
n = len(arr)
for i in range(n):
rowsum = np.sum(arr[i])
if rowsum != 0:
arr[i] = arr[i] / rowsum
return arr
def _make_tempp(P, Ph, i, ntc):
Ap = P[i:ntc - 1, i + 1:ntc]
Bp = Ph[i + 1:ntc, i:ntc - 1]
dim_p = ntc - 1 - i
tempp = zeros((dim_p, 1))
I = np.eye(len(Ap))
if i == 1:
e = Ph[i + 1:ntc, 0]
else:
e = np.sum(Ph[i + 1:ntc, :i - 1], axis=1)
if max(abs(e)) > 1e-10:
if dim_p == 1:
tempp[0] = (Ap / (1 - Bp * Ap) * e)
else:
rh = I - np.dot(Bp, Ap)
tempp = np.dot(Ap, linalg.solve(rh, e))
# end
# end
return tempp
def _make_tempm(P, Ph, j, ntc, n):
Am = P[ntc-1:j, ntc:j+1]
Bm = Ph[ntc:j+1, ntc-1:j]
dim_m = j - ntc + 1
tempm = zeros((dim_m, 1))
Im = np.eye(len(Am))
if j == n - 1:
em = P[ntc-1:j, n]
else:
em = np.sum(P[ntc-1:j, j + 1:n], axis=1)
# end
if max(abs(em)) > 1e-10:
if dim_m == 1:
tempm[0] = (Bm / (1 - Am * Bm) * em)
else:
rh = Im - np.dot(Am, Bm)
tempm = np.dot(Bm, linalg.lstsq(rh, em)[0])
# end
# end
return tempm
if f_mM is None:
f_mM = np.copy(f_Mm) * 1.0
u = np.linspace(*param)
udisc = u[::-1] # np.fliplr(u)
ntc = np.sum(udisc >= utc)
n = len(f_Mm)
_check_ntc(ntc, n)
_check_discretization(param, ntc)
# normalization of frequency matrices
f_Mm = _normalize_rows(f_Mm)
P = np.fliplr(f_Mm)
Ph = np.rot90(np.fliplr(f_mM*1.0), -1)
Ph = _normalize_rows(Ph)
Ph = np.fliplr(Ph)
F = np.zeros((n, n))
F[:ntc - 1, :(n - ntc)] = f_mM[:ntc - 1, :(n - ntc)]
F = cmat2nt(F)
for i in range(1, ntc):
for j in range(ntc-1, n - 1):
if i < ntc-1:
tempp = _make_tempp(P, Ph, i, ntc)
b = np.dot(np.dot(tempp.T, f_mM[i:ntc - 1, n - j - 2::-1]),
ones((n - j - 1, 1)))
# end
if j > ntc-1:
tempm = _make_tempm(P, Ph, j, ntc, n)
c = np.dot(np.dot(ones((1, i)),
f_mM[:i, n - ntc-1:n - j - 2:-1]),
tempm)
# end
if (j > ntc-1) and (i < ntc-1):
a = np.dot(np.dot(tempp.T,
f_mM[i:ntc - 1, n - ntc - 1:-1:n - j + 1]),
tempm)
F[i, n - j - 1] = F[i, n - j - 1] + a + b + c
# end
if (j == ntc-1) and (i < ntc-1):
F[i, n - ntc] = F[i, n - ntc] + b
for k in range(ntc):
F[i, n - k - 1] = F[i, n - ntc]
# end
# end
if (j > ntc-1) and (i == ntc-1):
F[i, n - j - 1] = F[i, n - j - 1] + c
for k in range(ntc-1, n):
F[k, n - j - 1] = F[ntc-1, n - j - 1]
# end
# end
# end
# end
# fmax=max(max(F));
# contour (u,u,flipud(F),...
# fmax*[0.005 0.01 0.02 0.05 0.1 0.2 0.4 0.6 0.8])
# axis([param(1) param(2) param(1) param(2)])
# title('Crest-trough density')
# ylabel('crest'), xlabel('trough')
# axis('square')
# if mlver>1, commers, end
return nt2cmat(F)
def mctp2rfc(fmM, fMm=None):
'''
Return Rainflow matrix given a Markov chain of turning points
computes f_rfc = f_mM + F_mct(f_mM).
Parameters
----------
fmM = the min2max Markov matrix,
fMm = the max2min Markov matrix,
Returns
-------
f_rfc = the rainflow matrix,
Example:
-------
>>> fmM = np.array([[ 0.0183, 0.0160, 0.0002, 0.0000, 0],
... [0.0178, 0.5405, 0.0952, 0, 0],
... [0.0002, 0.0813, 0, 0, 0],
... [0.0000, 0, 0, 0, 0],
... [ 0, 0, 0, 0, 0]])
>>> np.allclose(mctp2rfc(fmM),
... [[ 2.669981e-02, 7.799700e-03, 4.906077e-07, 0.0, 0.0],
... [ 9.599629e-03, 5.485009e-01, 9.539951e-02, 0.0, 0.0],
... [ 5.622974e-07, 8.149944e-02, 0.0, 0.0, 0.0],
... [ 0.0, 0.0, 0.0, 0.0, 0.0],
... [ 0.0, 0.0, 0.0, 0.0, 0.0]], 1.e-7)
True
'''
def _get_PMm(AA1, MA, nA):
PMm = AA1.copy()
for j in range(nA):
norm = MA[j]
if norm != 0:
PMm[j, :] = PMm[j, :] / norm
PMm = np.fliplr(PMm)
return PMm
if fMm is None:
fmM = np.atleast_1d(fmM)
fMm = fmM
else:
fmM, fMm = np.atleast_1d(fmM, fMm)
f_mM, f_Mm = fmM.copy(), fMm.copy()
N = max(f_mM.shape)
f_max = np.sum(f_mM, axis=1)
f_min = np.sum(f_mM, axis=0)
f_rfc = zeros((N, N))
f_rfc[N - 2, 0] = f_max[N - 2]
f_rfc[0, N - 2] = f_min[N - 2]
for k in range(2, N - 1):
for i in range(1, k):
AA = f_mM[N - 1 - k:N - 1 - k + i, k - i:k]
AA1 = f_Mm[N - 1 - k:N - 1 - k + i, k - i:k]
RAA = f_rfc[N - 1 - k:N - 1 - k + i, k - i:k]
nA = max(AA.shape)
MA = f_max[N - 1 - k:N - 1 - k + i]
mA = f_min[k - i:k]
SA = AA.sum()
SRA = RAA.sum()
DRFC = SA - SRA
NT = min(mA[0] - sum(RAA[:, 0]), MA[0] - sum(RAA[0, :])) # check!
NT = max(NT, 0) # ??check
if NT > 1e-6 * max(MA[0], mA[0]):
NN = MA - np.sum(AA, axis=1) # T
e = (mA - np.sum(AA, axis=0)) # T
e = np.flipud(e)
PmM = np.rot90(AA.copy())
for j in range(nA):
norm = mA[nA - 1 - j]
if norm != 0:
PmM[j, :] = PmM[j, :] / norm
e[j] = e[j] / norm
# end
# end
fx = 0.0
if (max(np.abs(e)) > 1e-6 and
max(np.abs(NN)) > 1e-6 * max(MA[0], mA[0])):
PMm = _get_PMm(AA1, MA, nA)
A = PMm
B = PmM
if nA == 1:
fx = NN * (A / (1 - B * A) * e)
else:
rh = np.eye(A.shape[0]) - np.dot(B, A)
# least squares
fx = np.dot(NN, np.dot(A, linalg.solve(rh, e)))
# end
# end
f_rfc[N - 1 - k, k - i] = fx + DRFC
# check2=[ DRFC fx]
# pause
else:
f_rfc[N - 1 - k, k - i] = 0.0
# end
# end
m0 = max(0, f_min[0] - np.sum(f_rfc[N - k + 1:N, 0]))
M0 = max(0, f_max[N - 1 - k] - np.sum(f_rfc[N - 1 - k, 1:k]))
f_rfc[N - 1 - k, 0] = min(m0, M0)
# n_loops_left=N-k+1
# end
for k in range(1, N):
M0 = max(0, f_max[0] - np.sum(f_rfc[0, N - k:N]))
m0 = max(0, f_min[N - 1 - k] - np.sum(f_rfc[1:k + 1, N - 1 - k]))
f_rfc[0, N - 1 - k] = min(m0, M0)
# end
# clf
# subplot(1,2,2)
# pcolor(levels(paramm),levels(paramM),flipud(f_mM))
# title('Markov matrix')
# ylabel('max'), xlabel('min')
# axis([paramm(1) paramm(2) paramM(1) paramM(2)])
# axis('square')
#
# subplot(1,2,1)
# pcolor(levels(paramm),levels(paramM),flipud(f_rfc))
# title('Rainflow matrix')
# ylabel('max'), xlabel('rfc-min')
# axis([paramm(1) paramm(2) paramM(1) paramM(2)])
# axis('square')
return f_rfc
def rfcfilter(x, h, method=0):
"""
Rainflow filter a signal.
@ -2431,7 +2005,7 @@ def discretize(fun, a, b, tol=0.005, n=5, method='linear'):
tol : real, scalar
absoute error tolerance
n : scalar integer
number of values
number of values to start the discretization with.
method : string
defining method of gridding, options are 'linear' and 'adaptive'
@ -2482,7 +2056,7 @@ def _discretize_linear(fun, a, b, tol=0.005, n=5):
x = linspace(a, b, n)
y = fun(x)
y00 = interp(x, x0, y0)
err = 0.5 * amax(np.abs((y00 - y) / (np.abs(y00 + y) + _TINY)))
err = 0.5 * amax(np.abs(y00 - y) / (np.abs(y00) + np.abs(y) + _TINY + tol))
num_tries += int(abs(err - err0) <= tol/2)
return x, y
@ -2500,27 +2074,32 @@ def _discretize_adaptive(fun, a, b, tol=0.005, n=5):
err = erri.max()
err0 = inf
num_tries = 0
reltol = abstol = tol
for j in range(50):
if num_tries < 5 and np.any(erri > tol):
if num_tries < 5 and err > tol:
err0 = err
# find top errors
I, = where(erri > tol)
ix, = where(erri > tol)
# double the sample rate in intervals with the most error
y = (vstack(((x[I] + x[I - 1]) / 2,
(x[I + 1] + x[I]) / 2)).T).ravel()
y = (vstack(((x[ix] + x[ix - 1]) / 2,
(x[ix + 1] + x[ix]) / 2)).T).ravel()
fy = fun(y)
fy0 = interp(y, x, fx)
erri = 0.5 * (np.abs((fy0 - fy) / (np.abs(fy0 + fy) + _TINY)))
abserr = np.abs(fy0 - fy)
erri = 0.5 * (abserr / (np.abs(fy0) + np.abs(fy) + _TINY + tol))
# abserr = np.abs(fy0 - fy)
# converged = abserr <= np.maximum(abseps, releps * abs(fy))
# converged = abserr <= np.maximum(tol, tol * abs(fy))
err = erri.max()
x = hstack((x, y))
I = x.argsort()
x = x[I]
erri = hstack((zeros(len(fx)), erri))[I]
fx = hstack((fx, fy))[I]
ix = x.argsort()
x = x[ix]
erri = hstack((zeros(len(fx)), erri))[ix]
fx = hstack((fx, fy))[ix]
num_tries += int(abs(err - err0) <= tol/2)
else:
break

260
wafo/objects.py
Unescape Escape View File

@ -609,6 +609,23 @@ class LevelCrossings(PlotData):
return estimate._trdata_lc(self, mean, sigma)
class CycleMatrix(PlotData):
"""
Container class for Cycle Matrix data objects in WAFO
"""
def __init__(self, *args, **kwds):
self.kind = kwds.pop('kind', 'min2max')
self.sigma = kwds.pop('sigma', None)
self.mean = kwds.pop('mean', None)
self.time = kwds.pop('time', 1)
options = dict(title=self.kind + ' cycle matrix',
xlab='min', ylab='max',
plot_args=['b.'])
options.update(**kwds)
super(CycleMatrix, self).__init__(*args, **options)
class CyclePairs(PlotData):
'''
Container class for Cycle Pairs data objects in WAFO
@ -797,6 +814,249 @@ class CyclePairs(PlotData):
return LevelCrossings(dcount, levels, mean=self.mean, sigma=self.sigma,
ylab=ylab, intensity=intensity)
def _smoothcmat(F, method=1, h=None, NOsubzero=0, alpha=0.5):
"""
SMOOTHCMAT Smooth a cycle matrix using (adaptive) kernel smoothing
CALL: Fsmooth = smoothcmat(F,method);
Fsmooth = smoothcmat(F,method,[],NOsubzero);
Fsmooth = smoothcmat(F,2,h,NOsubzero,alpha);
Input:
F = Cycle matrix. [nxn]
method = 1: Kernel estimator (constant bandwidth). (Default)
2: Adaptiv kernel estimator (local bandwidth).
h = Bandwidth (Optional, Default='automatic choice')
NOsubzero = Number of subdiagonals that are zero
(Optional, Default = 0, only the diagonal is zero)
alpha = Parameter for method (2) (Optional, Default=0.5).
A number between 0 and 1.
alpha=0 implies constant bandwidth (method 1).
alpha=1 implies most varying bandwidth.
Output:
F = Smoothed cycle matrix. [nxn]
h = Selected bandwidth.
See also
cc2cmat, tp2rfc, tp2mm, dat2tp
"""
aut_h = h is None
if method not in [1, 2]:
raise ValueError('Input argument "method" should be 1 or 2')
n = len(F) # Size of matrix
N = np.sum(F) # Total number of cycles
Fsmooth = np.zeros((n,n))
if method == 1 or method == 2: # Kernel estimator
d = 2 # 2-dim
x = np.arange(n)
I, J = np.meshgrid(x, x)
# Choosing bandwidth
# This choice is optimal if the sample is from a normal distr.
# The normal bandwidth usualy oversmooths,
# therefore we choose a slightly smaller bandwidth
if aut_h == 1:
h_norm = smoothcmat_hnorm(F,NOsubzero);
h = 0.7*h_norm # Don't oversmooth
#h0 = N^(-1/(d+4));
#FF = F+F';
#mean_F = sum(sum(FF).*(1:n))/N/2;
#s2 = sum(sum(FF).*((1:n)-mean_F).^2)/N/2;
#s = sqrt(s2); % Mean of std in each direction
#h_norm = s*h0; % Optimal for Normal distr.
#h = h_norm; % Test
# endif
# Calculating kernel estimate
# Kernel: 2-dim normal density function
for i in range(n-1):
for j in range(i+1,n):
if F(i,j) != 0:
F1 = exp(-1/(2*h**2)*((I-i)**2+(J-j)**2)); # Gaussian kernel
F1 = F1+F1.T; # Mirror kernel in diagonal
F1 = np.triu(F1,1+NOsubzero); # Set to zero below and on diagonal
F1 = F[i,j] * F1/np.sum(F1) # Normalize
Fsmooth = Fsmooth+F1;
# endif
# endfor
# endfor
# endif method 1 or 2
if method == 2:
Fpilot = Fsmooth/N;
Fsmooth = np.zeros(n,n);
[I1,I2] = find(F>0);
logg = 0;
for i in range(len(I1)): # =1:length(I1):
logg = logg + F(I1(i),I2(i)) * log(Fpilot(I1(i),I2(i)));
#endfor
g = np.exp(logg/N);
lamda = (Fpilot/g)**(-alpha);
for i in range(n-1): # = 1:n-1
for j in range(i+1, n): # = i+1:n
if F[i,j] != 0:
hi = h*lamda[i,j]
F1 = np.exp(-1/(2*hi**2)*((I-i)**2+(J-j)**2)); # Gaussian kernel
F1 = F1+F1.T; # Mirror kernel in diagonal
F1 = np.triu(F1,1+NOsubzero); # Set to zero below and on diagonal
F1 = F[i,j] * F1/np.sum(F1); # Normalize
Fsmooth = Fsmooth+F1;
# endif
# endfor
# endfor
#endif method 2
return Fsmooth,h
def cycle_matrix(self, param=(), ddef=1, method=0, h=None, NOsubzero=0, alpha=0.5):
"""CC2CMAT Calculates the cycle count matrix from a cycle count.
using (0) Histogram, (1) Kernel smoothing, (2) Kernel smoothing.
CALL: [F,h] = cc2cmat(param,cc,ddef,method,h,NOsubzero,alpha);
Input:
param = Parameter vector, [a b n], defines the grid.
cc = Cycle count with minima in column 1 and maxima in column 2. [nx2]
ddef = 1: causes peaks to be projected upwards and troughs
downwards to the closest discrete level (default).
= 0: causes peaks and troughs to be projected
the closest discrete level.
= -1: causes peaks to be projected downwards and the
troughs upwards to the closest discrete level.
method = 0: Histogram. (Default)
1: Kernel estimator (constant bandwidth).
2: Adaptiv kernel estimator (local bandwidth).
h = Bandwidth (Optional, Default='automatic choice')
NOsubzero = Number of subdiagonals that are set to zero
(Optional, Default = 0, only the diagonal is zero)
alpha = Parameter for method (2) (Optional, Default=0.5).
A number between 0 and 1.
alpha=0 implies constant bandwidth (method 1).
alpha=1 implies most varying bandwidth.
Output:
F = Estimated cycle matrix.
h = Selected bandwidth.
See also
dcc2cmat, cc2dcc, smoothcmat
"""
if not 0 <= method <= 2:
raise ValueError('Input argument "method" should be 0, 1 or 2')
u = np.linspace(*param) # Discretization levels
n = param[2] # size of matrix
# Compute Histogram
dcp = self._discretize_cycle_pairs(param, ddef)
F = self._dcp2cmat(dcp, n)
# Smooth by using Kernel estimator ?
#if method >= 1:
# F, h = smoothcmat(F,method, h, NOsubzero, alpha)
return CycleMatrix(F, u, u)
def _dcp2cmat(self, dcp, n):
"""
DCP2CMAT Calculates the cycle matrix for a discrete cycle pairs.
CALL: F = dcc2cmat(dcc,n);
F = Cycle matrix
dcc = a two column matrix with a discrete cycle count.
n = Number of discrete levels.
The discrete cycle count takes values from 1 to n.
A cycle count is transformed into a discrete cycle count by
using the function CC2DCC.
See also cc2cmat, cc2dcc, cmatplot
"""
F = np.zeros((n, n));
cp1, cp2 = dcp
for i, j in zip(cp1, cp2):
F[i, j] += 1
return F
def _discretize_cycle_pairs(self, param, ddef=1):
"""
Discretize a cycle pairs.
Parameters
----------
param = the parameter matrix.
ddef = 1 causes peaks to be projected upwards and troughs
downwards to the closest discrete level (default).
= 0 causes peaks and troughs to be projected to
the closest discrete level.
=-1 causes peaks to be projected downwards and the
troughs upwards to the closest discrete level.
Returns
-------
dcc = a two column matrix with discrete classes.
Example:
x = load('sea.dat');
tp = dat2tp(x);
rfc = tp2rfc(tp);
param = [-2, 2, 41];
dcc = cc2dcc(param,rfc);
u = levels(param);
Frfc = dcc2cmat(dcc,param(3));
cmatplot(u,u,{Frfc}, 4);
close all;
See also cc2cmat, dcc2cmat, dcc2cc
"""
cp1, cp2 = np.copy(self.args), np.copy(self.data)
# Make so that minima is in first column
ix = np.flatnonzero(cp1>cp2)
if np.any(ix):
cp1[ix], cp2[ix] = cp2[ix], cp1[ix]
# Make discretization
a, b, n = param
delta = (b-a)/(n-1) # Discretization step
cp1 = (cp1-a)/delta + 1
cp2 = (cp2-a)/delta + 1
if ddef == 0:
cp1 = np.clip(np.round(cp1), 0, n-1)
cp2 = np.clip(np.round(cp2), 0, n-1)
elif ddef == +1:
cp1 = np.clip(np.floor(cp1), 0, n-2)
cp2 = np.clip(np.ceil(cp2), 1, n-1)
elif ddef == -1:
cp1 = np.clip(np.ceil(cp1), 1, n-1)
cp2 = np.clip(np.floor(cp2), 0, n-2)
else:
raise ValueError('Undefined discretization definition, ddef = {}'.format(ddef))
if np.any(ix):
cp1[ix], cp2[ix] = cp2[ix], cp1[ix]
return np.asarray(cp1, type=int), np.asarray(cp2, type=int)
class TurningPoints(PlotData):

5
wafo/spectrum/core.py
Unescape Escape View File

@ -18,8 +18,9 @@ from ..objects import TimeSeries, mat2timeseries
from ..interpolate import stineman_interp
from ..wave_theory.dispersion_relation import w2k # , k2w
from ..containers import PlotData, now
from ..misc import sub_dict_select, nextpow2, discretize, JITImport, mctp2tc
from ..misc import meshgrid, gravity, cart2polar, polar2cart, mctp2rfc
from ..misc import sub_dict_select, nextpow2, discretize, JITImport
from ..misc import meshgrid, gravity, cart2polar, polar2cart
from ..markov import mctp2rfc, mctp2tc
from ..kdetools import qlevels
# from wafo.transform import TrData

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