Source code for PyMca5.PyMcaMath.SpecArithmetic
#/*##########################################################################
#
# The PyMca X-Ray Fluorescence Toolkit
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# Copyright (c) 2004-2014 European Synchrotron Radiation Facility
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__author__ = "V.A. Sole - ESRF Data Analysis"
__contact__ = "sole@esrf.fr"
__license__ = "MIT"
__copyright__ = "European Synchrotron Radiation Facility, Grenoble, France"
__doc__ = """
This module implements several mathematical functions:
- peak search
- center of mass search
- fwhm search
WARNING : array are numpy.ndarray objects.
"""
import numpy
[docs]def search_peak(xdata, ydata):
"""
Search a peak and its position in arrays xdata ad ydata.
Return three integer:
- peak position
- peak value
- index of peak position in array xdata
This result may accelerate the fwhm search.
"""
ymax = max(ydata)
idx = __give_index(ymax,ydata)
return xdata[idx],ymax,idx
[docs]def search_com(xdata,ydata):
"""
Return the center of mass in arrays xdata and ydata
"""
num = numpy.sum(xdata*ydata)
denom = numpy.sum(ydata).astype(numpy.float)
try:
result = num/denom
except ZeroDivisionError:
result = 0
return result
[docs]def search_fwhm(xdata,ydata,peak=None,index=None):
"""
Search a fwhm and its center in arrays xdata and ydatas.
If no fwhm is found, (0,0) is returned.
peak and index which are coming from search_peak result, may
accelerate calculation
"""
if peak is None or index is None:
x,mypeak,index_peak = search_peak(xdata,ydata)
else:
mypeak = peak
index_peak = index
hm = mypeak/2
idx = index_peak
try:
while ydata[idx] >= hm:
idx = idx-1
x0 = xdata[idx]
x1 = xdata[idx+1]
y0 = ydata[idx]
y1 = ydata[idx+1]
lhmx = (hm*(x1-x0) - (y0*x1)+(y1*x0)) / (y1-y0)
except ZeroDivisionError:
lhmx = 0
except IndexError:
lhmx = xdata[0]
idx = index_peak
try:
while ydata[idx] >= hm:
idx = idx+1
x0 = xdata[idx]
x1 = xdata[idx+1]
y0 = ydata[idx]
y1 = ydata[idx+1]
uhmx = (hm*(x1-x0) - (y0*x1)+(y1*x0)) / (y1-y0)
except ZeroDivisionError:
uhmx = 0
except IndexError:
uhmx = xdata[-1]
FWHM = uhmx - lhmx
CFWHM = (uhmx+lhmx)/2
return FWHM,CFWHM
def __give_index(elem,array):
"""
Return the index of elem in array
"""
mylist = array.tolist()
return mylist.index(elem)
if __name__ == '__main__':
test()