diff --git a/fluents/lib/engines.py b/fluents/lib/engines.py
index 8f529e5..219f1ce 100644
--- a/fluents/lib/engines.py
+++ b/fluents/lib/engines.py
@@ -13,9 +13,8 @@ try:
     from symeig import symeig
 except:
     has_sym = False
-has_sym=False
 
-def pca(a, aopt,scale='scores',mode='normal',center_axis=-1):
+def pca(a, aopt,scale='scores',mode='normal',center_axis=0):
     """ Principal Component Analysis.
 
     Performs PCA on given matrix and returns results in a dictionary.
@@ -26,7 +25,7 @@ def pca(a, aopt,scale='scores',mode='normal',center_axis=-1):
         aopt : int
     Number of components to use, aopt<=min(samples, variables)
 
-    :Returns:  
+    :Returns:
     results : dict
         keys -- values,  T -- scores, P -- loadings, E -- residuals,
         lev --leverages, ssq -- sum of squares, expvar -- cumulative
@@ -42,14 +41,15 @@ def pca(a, aopt,scale='scores',mode='normal',center_axis=-1):
         - pcr : other blm
         - pls : other blm
         - lpls : other blm
- 
+
     Notes
     -----
 
     Uses kernel speed-up if m>>n or m<<n.
 
     If residuals turn rank deficient, a lower number of component than given
-    in input will be used. The number of components used is given in results-dict. 
+    in input will be used. The number of components used is given in
+    results-dict.
     
     Examples
     --------
@@ -57,7 +57,7 @@ def pca(a, aopt,scale='scores',mode='normal',center_axis=-1):
     >>> import scipy,engines
     >>> a=scipy.asarray([[1,2,3],[2,4,5]])
     >>> dat=engines.pca(a, 2)
-    >>> dat['expvar']
+    >>> dat['expvarx']
     array([0.,99.8561562,  100.])
 
     """
@@ -76,7 +76,6 @@ def pca(a, aopt,scale='scores',mode='normal',center_axis=-1):
     aopt = minimum(aopt, eff_rank)
     T = u*s
     s = s[:aopt]
-    e = e[:aopt]
     T = T[:,:aopt]
     P = v[:,:aopt]
     
@@ -91,7 +90,6 @@ def pca(a, aopt,scale='scores',mode='normal',center_axis=-1):
         E = empty((aopt, m, n))
         ssq = []
         lev = []
-        expvarx = empty((aopt, aopt+1))
         for ai in range(aopt):
             E[ai,:,:] = a - dot(T[:,:ai+1], P[:,:ai+1].T)
             ssq.append([(E[ai,:,:]**2).sum(0), (E[ai,:,:]**2).sum(1)])
@@ -99,9 +97,6 @@ def pca(a, aopt,scale='scores',mode='normal',center_axis=-1):
                 lev.append([((s*T)**2).sum(1), (P**2).sum(1)])
             else:
                 lev.append([(T**2).sum(1), ((s*P)**2).sum(1)])
-        
-            expvarx[ai,:] = r_[0, 100*e.cumsum()/e.sum()]
-        
     else:
         # residuals
         E = a - dot(T, P.T)
@@ -112,9 +107,9 @@ def pca(a, aopt,scale='scores',mode='normal',center_axis=-1):
             lev = [(1./m)+(T**2).sum(1), (1./n)+((P/s)**2).sum(1)]
         else:
             lev = [(1./m)+((T/s)**2).sum(1), (1./n)+(P**2).sum(1)]
-        # variances        
-        expvarx = r_[0, 100*e.cumsum()/e.sum()]
-        
+        # variances
+    expvarx = r_[0, 100*e.cumsum()/e.sum()][:aopt+1]
+    
     return {'T':T, 'P':P, 'E':E, 'expvarx':expvarx, 'levx':lev, 'ssqx':ssq, 'aopt':aopt}
 
 def pcr(a, b, aopt, scale='scores',mode='normal',center_axis=0):
@@ -130,7 +125,7 @@ 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
@@ -143,7 +138,7 @@ def pcr(a, b, aopt, scale='scores',mode='normal',center_axis=0):
         Center along given axis. If neg.: no centering (-inf,..., matrix modes)
   
     :SeeAlso:
-        - pcr : other blm
+        - pca : other blm
         - pls : other blm
         - lpls : other blm
  
@@ -161,8 +156,9 @@ def pcr(a, b, aopt, scale='scores',mode='normal',center_axis=0):
     
     >>> import scipy,engines
     >>> a=scipy.asarray([[1,2,3],[2,4,5]])
-    >>> dat=engines.pca(a, 2)
-    >>> dat['expvar']
+    >>> b=scipy.asarray([[1,1],[2,3]])
+    >>> dat=engines.pcr(a, 2)
+    >>> dat['expvarx']
     array([0.,99.8561562,  100.])
 
     """
@@ -171,12 +167,11 @@ def pcr(a, b, aopt, scale='scores',mode='normal',center_axis=0):
         b = b - expand_dims(b.mean(center_axis), center_axis)
     dat = pca(a, aopt=aopt, scale=scale, mode=mode, center_axis=center_axis)
     T = dat['T']
-    weights = apply_along_axis(vnorm, 0, T)
+    weights = apply_along_axis(vnorm, 0, T)**2
     if scale=='loads':
-        # fixme: check weights
-        Q = dot(b.T, T*weights**2)
+        Q = dot(b.T, T*weights)
     else:
-        Q = dot(b.T, T/weights**2)
+        Q = dot(b.T, T/weights)
 
     if mode=='fast':
         dat.update({'Q':Q})
@@ -187,43 +182,96 @@ def pcr(a, b, aopt, scale='scores',mode='normal',center_axis=0):
             F[i,:,:] = b - dot(T[:,:i+1], Q[:,:i+1].T)
     else:
         F = b - dot(T, Q.T)
-    #fixme: explained variance in Y + Y-var leverages
-    dat.update({'Q':Q, 'F':F})
+    expvary = r_[0,  100*((T**2).sum(0)*(Q**2).sum(0)/(b**2).sum()).cumsum()[:aopt]]
+    #fixme: Y-var leverages
+    dat.update({'Q':Q, 'F':F, 'expvary':expvary})
     return dat
 
-def pls(a, b, aopt=2, scale='scores', mode='normal', ab=None):
+def pls(a, b, aopt=2, scale='scores', mode='normal', ax_center=0, ab=None):
     """Partial Least Squares Regression.
 
-    Applies plsr to given matrices and returns results in a dictionary.
+    Performs PLS on given matrix and returns results in a dictionary.
+
+    :Parameters:
+        a : array
+    Data measurement matrix, (samples x variables)
+        b : array
+    Data response matrix, (samples x responses)
+        aopt : int
+    Number of components to use, aopt<=min(samples, variables)
+
+    :Returns:
+    results : dict
+        keys -- values,  T -- scores, P -- loadings, E -- residuals,
+        levx -- leverages, ssqx -- sum of squares, expvarx -- cumulative
+        explained variance of descriptors, expvary -- cumulative explained
+        variance of responses, aopt -- number of components used
+    
+    :OtherParameters:
+    mode : str
+        Amount of info retained, ('fast', 'normal', 'detailed')
+    center_axis : int
+        Center along given axis. If neg.: no centering (-inf,..., matrix modes)
+    
+    :SeeAlso:
+        - pca : other blm
+        - pcr : other blm
+        - lpls : other blm
+ 
+    Notes
+    -----
+
+    Uses kernel speed-up if m>>n or m<<n.
+
+    If residuals turn rank deficient, a lower number of component than given
+    in input will be used. The number of components used is given in results-dict.
+
+    Examples
+    --------
+    
+    >>> import scipy,engines
+    >>> a=scipy.asarray([[1,2,3],[2,4,5]])
+    >>> b=scipy.asarray([[1,1],[2,3]])
+    >>> dat=engines.pls(a, b, 2)
+    >>> dat['expvarx']
+    array([0.,99.8561562,  100.])
 
-    Fast pls for calibration. Only inefficient for many Y-vars.
     """
-    m, n = a.shape
+    
+    m, n = m_shape(a)
     if ab!=None:
-        mm, ll = m_shape(ab)
+        mm, l = m_shape(ab)
+        assert(m==mm)
     else:
          k, l = m_shape(b)
-    assert(m==mm)
-    assert(l==ll)
+    
     W = empty((n, aopt))
     P = empty((n, aopt))
     R = empty((n, aopt))
     Q = empty((l, aopt))
     T = empty((m, aopt))
     B = empty((aopt, n, l))
-
+    
     if ab==None:
         ab = dot(a.T, b)
     for i in range(aopt):
         if ab.shape[1]==1:
             w = ab.reshape(n, l)
+            w = w/vnorm(w)
+        elif n<l:
+            if has_sym:
+                s, u = symeig(dot(ab.T, ab),range=[l,l],overwrite=True)
+            else:
+                u, s, vh = svd(dot(ab, ab.T))
+            w = u[:,0]
         else:
-            u, s, vh = svd(dot(ab.T, ab))
-            w = dot(ab, u[:,:1])
-
-        w = w/vnorm(w)
+            if has_sym:
+                s, u = symeig(dot(ab.T, ab),range=[l,l],overwrite=True)
+            else:
+                u, s, vh = svd(dot(ab.T, ab))
+            w = dot(ab, u)
         r = w.copy()
-        if i>0: # recursive estimate to 
+        if i>0:
             for j in range(0, i, 1):
                 r = r - dot(P[:,j].T, w)*R[:,j][:,newaxis]
         t = dot(a, r)
@@ -233,8 +281,6 @@ def pls(a, b, aopt=2, scale='scores', mode='normal', ab=None):
         ab = ab - dot(p, q.T)*tt
         T[:,i] = t.ravel()
         W[:,i] = w.ravel()
-        P[:,i] = p.ravel()
-        R[:,i] = r.ravel()
 
         if mode=='fast' and i==aopt-1:
             if scale=='loads':
@@ -243,6 +289,8 @@ def pls(a, b, aopt=2, scale='scores', mode='normal', ab=None):
                 W = W*tnorm
             return {'T':T, 'W':W}
 
+        P[:,i] = p.ravel()
+        R[:,i] = r.ravel()
         Q[:,i] = q.ravel()
         B[i] = dot(R[:,:i+1], Q[:,:i+1].T)
 
@@ -272,14 +320,14 @@ def w_simpls(aat, b, aopt):
     """
     bb = b.copy()
     m, m = aat.shape
-    U = empty((m, aopt))
+    U = empty((m, aopt)) # W
     T = empty((m, aopt))
-    H = empty((m, aopt)) #just like W in simpls
-    PROJ = empty((m, aopt)) #just like R in simpls
+    H = empty((m, aopt)) # R
+    PROJ = empty((m, aopt)) # P?
 
     for i in range(aopt):
-        u, s, vh = svd(dot(dot(b.T, aat), b), full_matrices=0)
-        u = dot(b, u[:,:1]) #y-factor scores
+        q, s, vh = svd(dot(dot(b.T, aat), b), full_matrices=0)
+        u = dot(b, q[:,:1]) #y-factor scores
         U[:,i] = u.ravel()
         t = dot(aat, u)
         t = t/vnorm(t)
@@ -293,6 +341,38 @@ def w_simpls(aat, b, aopt):
 
     return {'T':T, 'U':U, 'Q':C, 'H':H}
 
+def w_pls(aat, b, aopt):
+    """ Pls for wide matrices.
+    Fast pls for crossval, used in calc rmsep for wide X
+    There is no P or W.  T is normalised
+    """
+    bb = b.copy()
+    m, m = aat.shape
+    U = empty((m, aopt)) # W
+    T = empty((m, aopt))
+    R = empty((m, aopt)) # R
+    PROJ = empty((m, aopt)) # P?
+
+    for i in range(aopt):
+        if has_sym:
+            pass
+        else:
+            q, s, vh = svd(dot(dot(b.T, aat), b), full_matrices=0)
+            q = q[:,:1]
+        u = dot(b , q) #y-factor scores
+        U[:,i] = u.ravel()
+        t = dot(aat, u)
+        t = t/vnorm(t)
+        T[:,i] = t.ravel()
+        r = dot(aat, t) #score-weights
+        R[:,i] = r.ravel()
+        PROJ[:,: i+1] = dot(T[:,:i+1], inv(dot(T[:,:i+1].T, R[:,:i+1])) )
+        if i<aopt:
+            b = b - dot(PROJ[:,:i+1], dot(R[:,:i+1].T,b) )
+    C = dot(bb.T, T)
+
+    return {'T':T, 'U':U, 'Q':C, 'H':H}
+
 def bridge(a, b, aopt, scale='scores', mode='normal', r=0):
     """Undeflated Ridged svd(X'Y)
     """
diff --git a/fluents/lib/select_generators.py b/fluents/lib/select_generators.py
index d791402..ac94c26 100644
--- a/fluents/lib/select_generators.py
+++ b/fluents/lib/select_generators.py
@@ -16,8 +16,9 @@ def w_pls_gen(aat,b,n_blocks=None,center=True,index_out=False):
      Returns:
          -- aat_in,aat_out,b_in,b_out,[out]
      """
-     m,n = aat.shape
+     m, n = aat.shape
      index = randperm(m)
+     if n_blocks==None: n_blocks = m
      nValuesInBlock = m/n_blocks
      if n_blocks==m:
          index = arange(m)
@@ -31,7 +32,7 @@ def w_pls_gen(aat,b,n_blocks=None,center=True,index_out=False):
           b_out = b[out,:]
           if center:
                aat_in, mn = outerprod_centering(aat_in)
-               aat_out = aat_out - mn
+               b_in = b_in - b_in.mean(0) # b_in + b_out/(b_in.shape[0])
           if index_out:
                yield aat_in,aat_out,b_in,b_out,out
           else:
@@ -217,7 +218,7 @@ def outerprod_centering(aat, ret_mn=True):
     mn_a = h + h.T # beauty of broadcasting
     aatc = aat - mn_a
     if ret_mn:
-        return aatc, mn_a
+        return aatc, h
     return aatc
      
      
diff --git a/fluents/lib/validation.py b/fluents/lib/validation.py
index 1049b1f..eb49197 100644
--- a/fluents/lib/validation.py
+++ b/fluents/lib/validation.py
@@ -61,7 +61,6 @@ def w_pls_cv_val(X, Y, amax, n_blocks=None, algo='simpls'):
     V = w_pls_gen(XXt, Y, n_blocks=n_blocks, center=True)
     for Din, Doi, Yin, Yout in V:
         ym = -sum(Yout, 0)[newaxis]/(1.0*Yin.shape[0])
-        Yin = Yin - ym
         PRESS[:,0] = PRESS[:,0] + ((Yout - ym)**2).sum(0)
         if algo=='simpls':
             dat = w_simpls(Din, Yin, amax)
@@ -74,15 +73,14 @@ def w_pls_cv_val(X, Y, amax, n_blocks=None, algo='simpls'):
         for j in range(l):
             TQ = dot(That, triu(dot(Q[j,:][:,newaxis], ones((1,amax)))) )
             E = Yout[:,j][:,newaxis] - TQ
-            E = E + sum(E, 0)/Din.shape[0]
+            E = E + sum(E, 0)/Din.shape[0] 
             PRESS[j,1:] = PRESS[j,1:] + sum(E**2, 0)
-    Yhat = Y - dot(That,Q.T)
-    rmsep = sqrt(PRESS/Y.shape[0])
-    aopt = find_aopt_from_sep(rmsep)
-    return rmsep, Yhat, aopt
+    #Yhat = Yin - dot(That,Q.T)
+    msep = PRESS/(Y.shape[0])
+    aopt = find_aopt_from_sep(msep)
+    return sqrt(msep)
 
 def pls_val(X, Y, amax=2, n_blocks=10, algo='pls', metric=None):
-    
     k, l = m_shape(Y)
     PRESS = zeros((l, amax+1), dtype='<f8')
     EE = zeros((amax, k, l), dtype='<f8')
@@ -105,9 +103,10 @@ def pls_val(X, Y, amax=2, n_blocks=10, algo='pls', metric=None):
             EE[a,out,:] = E
             PRESS[:,a+1] = PRESS[:,a+1] + sum(E**2,0)
 
-    rmsep = sqrt(PRESS/(k-1.))
-    aopt = find_aopt_from_sep(rmsep)
-    return rmsep, Yhat, aopt
+    #rmsep = sqrt(PRESS/(k-1.))
+    msep = PRESS
+    aopt = find_aopt_from_sep(msep)
+    return msep, Yhat, aopt
 
 def lpls_val(X, Y, Z, a_max=2, nsets=None,alpha=.5):
     """Performs crossvalidation to get generalisation error in lpls"""
@@ -270,7 +269,7 @@ def lpls_jk(X, Y, Z, a_max, nsets=None, alpha=.5):
 def find_aopt_from_sep(sep, method='75perc'):
     """Returns an estimate of optimal number of components from rmsecv.
     """
-
+    sep = sep.copy()
     if method=='vanilla':
         # min rmsep
         rmsecv = sqrt(sep.mean(0))
@@ -282,7 +281,7 @@ def find_aopt_from_sep(sep, method='75perc'):
         med = median(sep)
         prc_75 = []
         for col in sep.T:
-            col.sort()
+            col.sort() #this is inplace -> ruins sep, so we are doing a copy
             prc_75.append(col[int(ind)])
         prc_75 = array(prc_75)
         for i in range(1, sep.shape[1], 1):