def iahistogram(f):
""" o Purpose
Image histogram.
o Synopsis
h = iahistogram(f)
o Input
f:
o Output
h:
o Description
o Examples
f = iaread('woodlog.pgm')
iashow(f)
h = iahistogram(f)
g,d = iaplot(h)
g('set data style boxes')
g.plot(d)
showfig(h)
"""
from Numeric import asarray,searchsorted,sort,ravel,concatenate,product
f = asarray(f)
n = searchsorted(sort(ravel(f)), range(max(ravel(f))+1))
n = concatenate([n, [product(f.shape)]])
h = n[1:]-n[:-1]
return h
def column_degeneracy(a,cutoff=.5):
"""Returns the number of characters that's needed to cover >= cutoff
a: Numeric array
cutoff: number that should be covered in the array
Example:
[ [.1 .8 .3],
[.3 .2 .3],
[.6 0 .4]]
if cutoff = .75: column_degeneracy -> [2,1,3]
if cutoff = .45: column_degeneracy -> [1,1,2]
WARNING: watch out with floating point numbers.
if the cutoff= 0.9 and in the array is also 0.9, it might not be found
>>> searchsorted(cumsum(array([.6,.3,.1])),.9)
2
>>> searchsorted(cumsum(array([.5,.4,.1])),.9)
1
If the cutoff value is not found, the result is clipped to the
number of rows in the array.
"""
if not a:
return []
b = cumsum(sort(a,0)[::-1])
try:
degen = [searchsorted(b[:,idx],cutoff) for idx in range(len(b[0]))]
except TypeError:
raise ValueError, "Array has to be two dimensional"
#degen contains now the indices at which the cutoff was hit
#to change to the number of characters, add 1
return clip(array(degen)+1,0,a.shape[0])
def row_degeneracy(a,cutoff=.5):
"""Returns the number of characters that's needed to cover >= cutoff
a: Numeric array
cutoff: number that should be covered in the array
Example:
[ [.1 .3 .4 .2],
[.5 .3 0 .2],
[.8 0 .1 .1]]
if cutoff = .75: row_degeneracy -> [3,2,1]
if cutoff = .95: row_degeneracy -> [4,3,3]
WARNING: watch out with floating point numbers.
if the cutoff= 0.9 and in the array is also 0.9, it might not be found
>>> searchsorted(cumsum(array([.6,.3,.1])),.9)
2
>>> searchsorted(cumsum(array([.5,.4,.1])),.9)
1
If the cutoff value is not found, the result is clipped to the
number of columns in the array.
"""
if not a:
return []
try:
b = cumsum(sort(a)[:,::-1],1)
except IndexError:
raise ValueError, "Array has to be two dimensional"
degen = [searchsorted(aln_pos,cutoff) for aln_pos in b]
#degen contains now the indices at which the cutoff was hit
#to change to the number of characters, add 1
return clip(array(degen)+1,0,a.shape[1])
def rotationalConstants(self, conf=None):
"""Returns a sorted array of rotational constants A, B, C
in internal units."""
from Numeric import sort
from Units import h, pi
com, i = self.centerAndMomentOfInertia(conf)
pmi = i.eigenvalues()
return sort(h / (8.*pi*pi*pmi))[::-1]
