DAMASK_EICMD/processing/post/addDerivative.py

75 lines
2.7 KiB
Python
Executable File

#!/usr/bin/env python3
import os
import sys
from io import StringIO
from optparse import OptionParser
import numpy as np
import damask
scriptName = os.path.splitext(os.path.basename(__file__))[0]
scriptID = ' '.join([scriptName,damask.version])
def derivative(coordinates,what):
result = np.empty_like(what)
# use differentiation by interpolation
# as described in http://www2.math.umd.edu/~dlevy/classes/amsc466/lecture-notes/differentiation-chap.pdf
result[1:-1,:] = + what[1:-1,:] * (2.*coordinates[1:-1]-coordinates[:-2]-coordinates[2:]) / \
((coordinates[1:-1]-coordinates[:-2])*(coordinates[1:-1]-coordinates[2:])) \
+ what[2:,:] * (coordinates[1:-1]-coordinates[:-2]) / \
((coordinates[2:]-coordinates[1:-1])*(coordinates[2:]-coordinates[:-2])) \
+ what[:-2,:] * (coordinates[1:-1]-coordinates[2:]) / \
((coordinates[:-2]-coordinates[1:-1])*(coordinates[:-2]-coordinates[2:])) \
result[0,:] = (what[0,:] - what[1,:]) / \
(coordinates[0] - coordinates[1])
result[-1,:] = (what[-1,:] - what[-2,:]) / \
(coordinates[-1] - coordinates[-2])
return result
# --------------------------------------------------------------------
# MAIN
# --------------------------------------------------------------------
parser = OptionParser(option_class=damask.extendableOption, usage='%prog options [ASCIItable(s)]', description = """
Add column(s) containing numerical derivative of requested column(s) with respect to given coordinates.
""", version = scriptID)
parser.add_option('-c','--coordinates',
dest = 'coordinates',
type = 'string', metavar='string',
help = 'heading of coordinate column')
parser.add_option('-l','--label',
dest = 'labels',
action = 'extend', metavar = '<string LIST>',
help = 'heading of column(s) to differentiate')
(options,filenames) = parser.parse_args()
if filenames == []: filenames = [None]
if options.coordinates is None:
parser.error('no coordinate column specified.')
if options.labels is None:
parser.error('no data column specified.')
for name in filenames:
damask.util.report(scriptName,name)
table = damask.Table.load(StringIO(''.join(sys.stdin.read())) if name is None else name)
for label in options.labels:
table = table.add('d({})/d({})'.format(label,options.coordinates),
derivative(table.get(options.coordinates),table.get(label)),
scriptID+' '+' '.join(sys.argv[1:]))
table.save((sys.stdout if name is None else name), legacy=True)