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Mostly clean ups

This commit is contained in:
Arnar Flatberg 2007-11-27 15:05:19 +00:00
parent 2951ca4088
commit 4c809674bb
2 changed files with 98 additions and 84 deletions

View File

@ -12,7 +12,7 @@ from numpy.random import shuffle
from engines import nipals_lpls as lpls
def lpls_val(X, Y, Z, a_max=2, nsets=None,alpha=.5, mean_ctr=[2,0,2], zorth=False, verbose=True):
def lpls_val(X, Y, Z, a_max=2, nsets=None,alpha=.5, mean_ctr=[2,0,2], zorth=False, verbose=False):
"""Performs crossvalidation for generalisation error in lpls.
The L-PLS crossvalidation is estimated just like an ordinary pls
@ -80,11 +80,11 @@ def lpls_val(X, Y, Z, a_max=2, nsets=None,alpha=.5, mean_ctr=[2,0,2], zorth=Fals
if mean_ctr[0] != 1:
xi = X[val,:] - dat['mnx']
else:
xi = X[val] - X[val].mean(1)[:,newaxis]
xi = X[val] - X[cal].mean(1)[:,newaxis]
if mean_ctr[2] != 1:
ym = dat['mny']
else:
ym = Y[val].mean(1)[:,newaxis] #???: check this
ym = Y[cal].mean(1)[:,newaxis]
# predictions
for a in range(a_max):
Yhat[a,val,:] = atleast_2d(ym + dot(xi, dat['B'][a]))
@ -113,7 +113,7 @@ def lpls_val(X, Y, Z, a_max=2, nsets=None,alpha=.5, mean_ctr=[2,0,2], zorth=Fals
def pca_jk(a, aopt, n_blocks=None):
"""Returns jack-knife segements from PCA.
Parameters:
*Parameters*:
a : {array}
data matrix (n x m)
@ -122,21 +122,15 @@ def pca_jk(a, aopt, n_blocks=None):
nsets : {integer}
number of segments
Returns:
*Returns*:
Pcv : {array}
Loadings collected in a three way matrix (n_segments, m, aopt)
Notes:
- The loadings are scaled with the (1/samples)*eigenvalues.
*Notes*:
- Crossvalidation method is currently set to random blocks of samples.
- todo: add support for T
- fixme: more efficient to add this in validation loop?
"""
if nsets == None:
nsets = a.shape[0]
@ -305,6 +299,7 @@ def cv(N, K, randomise=True, sequential=False):
of length ~N/K, *without* replacement.
*Parameters*:
N : {integer}
Total number of samples
K : {integer}

View File

@ -12,13 +12,14 @@ minimum
from numpy.linalg import inv,svd
from scipy.sandbox import arpack
def pca(X, aopt, scale='scores', mode='normal', center_axis=0):
""" Principal Component Analysis.
PCA is a low rank bilinear aprroximation to a data matrix that sequentially
extracts orthogonal components of maximum variance.
Parameters:
*Parameters*:
X : {array}
Data measurement matrix, (samples x variables)
@ -27,7 +28,7 @@ def pca(X, aopt, scale='scores', mode='normal', center_axis=0):
center_axis : {integer}
Center along given axis. If neg.: no centering (-inf,..., matrix modes)
Returns:
*Returns*:
T : {array}
Scores, (samples, components)
@ -47,7 +48,7 @@ def pca(X, aopt, scale='scores', mode='normal', center_axis=0):
leverage : {array}
Leverages, (samples,)
OtherParameters:
*OtherParameters*:
scale : {string}, optional
Where to put the weights [['scores'], 'loadings']
@ -55,7 +56,7 @@ def pca(X, aopt, scale='scores', mode='normal', center_axis=0):
Amount of info retained, [['normal'], 'fast', 'detailed']
:SeeAlso:
*SeeAlso*:
`center` : Data centering
@ -78,9 +79,11 @@ def pca(X, aopt, scale='scores', mode='normal', center_axis=0):
"""
m, n = X.shape
assert(aopt<=min(m,n))
min_aopt = min(m, n)
if center_axis >= 0:
X = X - expand_dims(X.mean(center_axis), center_axis)
min_aopt = min_aopt - 1
assert(aopt <= min_aopt)
if m > (n+100) or n > (m+100):
u, s, v = esvd(X, aopt)
else:
@ -139,7 +142,7 @@ def pcr(a, b, aopt, scale='scores',mode='normal',center_axis=0):
Performs PCR on given matrix and returns results in a dictionary.
Parameters:
*Parameters*:
a : array
Data measurement matrix, (samples x variables)
@ -148,18 +151,18 @@ def pcr(a, b, aopt, scale='scores',mode='normal',center_axis=0):
aopt : int
Number of components to use, aopt<=min(samples, variables)
Returns:
*Returns*:
results : dict
keys -- values, T -- scores, P -- loadings, E -- residuals,
levx -- leverages, ssqx -- sum of squares, expvarx -- cumulative
explained variance, aopt -- number of components used
OtherParameters:
*OtherParameters*:
mode : str
mode : {string}
Amount of info retained, ('fast', 'normal', 'detailed')
center_axis : int
center_axis : {integer}
Center along given axis. If neg.: no centering (-inf,..., matrix modes)
SeeAlso:
@ -284,7 +287,7 @@ def pls(X, Y, aopt=2, scale='scores', mode='normal', center_axis=-1):
*SeeAlso*:
`center` : data centering
`center` - data centering
*Notes*
@ -311,13 +314,15 @@ def pls(X, Y, aopt=2, scale='scores', mode='normal', center_axis=-1):
Y = atleast_2d(Y).T
k, l = Y.shape
assert(m == k)
assert(aopt<min(m, n))
mnx, mny = 0, 0
min_aopt = min(m, n)
if center_axis >= 0:
mnx = expand_dims(X.mean(center_axis), center_axis)
X = X - mnx
min_aopt = min_aopt - 1
mny = expand_dims(Y.mean(center_axis), center_axis)
Y = Y - mny
assert(aopt > 0 and aopt < min_aopt)
W = empty((n, aopt))
P = empty((n, aopt))
@ -356,7 +361,7 @@ def pls(X, Y, aopt=2, scale='scores', mode='normal', center_axis=-1):
T[:,i] = t.ravel()
W[:,i] = w.ravel()
if mode=='fast' and i==aopt-1:
if mode == 'fast' and i == (aopt - 1):
if scale == 'loads':
tnorm = sqrt(tt)
T = T/tnorm
@ -495,7 +500,7 @@ def nipals_lpls(X, Y, Z, a_max, alpha=.7, mean_ctr=[2, 0, 2], scale='scores', zo
m, n = X.shape
k, l = Y.shape
u, o = Z.shape
max_rank = min(m, n)
max_rank = min(m, n) + 1
assert (a_max > 0 and a_max < max_rank), "Number of comp error:\
tried: %d, max_rank: %d" %(a_max, max_rank)
@ -617,6 +622,20 @@ def nipals_lpls(X, Y, Z, a_max, alpha=.7, mean_ctr=[2, 0, 2], scale='scores', zo
return {'T':T, 'W':W, 'P':P, 'Q':Q, 'U':U, 'L':L, 'K':K, 'B':B, 'E': E, 'F': F, 'G': G, 'evx':evx, 'evy':evy, 'evz':evz,'mnx': mnX, 'mny': mnY, 'mnz': mnZ}
def lpls_predict(model_dict, x, aopt):
"""Predict lpls reponses from existing model on new data.
"""
try:
m, n = x.shape
except:
x = atleast_2d(x.shape)
m, n = x.shape
if 'B0' in model_dict.keys():
y = model_dict['B0'] + dot()
def vnorm(a):
"""Returns the norm of a vector.
@ -714,19 +733,19 @@ def _scale(a, axis):
return a - sc, sc
def esvd(data, a_max=None):
""" SVD with kernel calculation
"""SVD with kernel calculation.
Calculate subspaces of X'X or XX' depending on the shape
of the matrix.
Parameters:
*Parameters*:
data : {array}
Data matrix
a_max : {integer}
Number of components to extract
Returns:
*Returns*:
u : {array}
Right hand eigenvectors
@ -735,9 +754,9 @@ def esvd(data, a_max=None):
v : {array}
Left hand eigenvectors
notes:
*Notes*:
Uses Anoldi iterations (ARPACK)
Uses Anoldi iterations for the symmetric eigendecomp (ARPACK)
"""