separation.py

Go to the documentation of this file.

 
r"""
Contains functionality to separate cracks and set transfer lengths.
\author Bertram Richter
\date 2022
"""
 
import copy
import numpy as np
 
from fosanalysis import utils
 
from . import cracks
 
class CrackLengths(utils.base.Task):
    r"""
    Assigns the transfer length to a all \ref cracks.Crack objects in a \ref cracks.CrackList.
    """
    def __init__(self, **methods: dict):
        r"""
        Constructs a CrackLength object.
        \param methods \copybrief methods For more, see \ref methods.
        """
        
        self.methods = methods if methods else {"min": True, "length": 0.2, "reset": "inner"}
    def _first_index_leq_threshold(self, data, threshold) -> int:
        r"""
        Return the index of the first entry in `data`, that is less or equal than the given threshold and `None`, if no entry fulfills this condition.
        """
        for i, x in enumerate(data):
            if x <= threshold:
                return i
        return None
    def run(self,
            x,
            strain,
            crack_list: cracks.CrackList) -> cracks.CrackList:
        r"""
        Estimates the transfer length of all cracks according to \ref methods.
        Limits that are `None` are replaced by \f$-\infty\f$ for the left and \f$\infty\f$ right limit prior to the assignments
        \param x Positional x values.
        \param strain List of strain values.
        \param crack_list \ref cracks.CrackList with \ref cracks.Crack objects, that already have assigned locations.
        \return Returns a \ref cracks.CrackList object.
        """
        crack_list.sort()
        for crack in crack_list:
            crack.x_l = crack.x_l if crack.x_l is not None else -np.inf
            crack.x_r = crack.x_r if crack.x_r is not None else np.inf
        methods = copy.deepcopy(self.methods)
        reset = methods.pop("reset", None)
        if reset is not None:
            for i, crack in enumerate(crack_list):
                if i < len(crack_list)-1 or reset == "all":
                    crack.x_r = np.inf
                if i > 0 or reset == "all":
                    crack.x_l = -np.inf
        for method, value in methods.items():
            for i, crack in enumerate(crack_list):
                if method == "middle":
                    if i > 0:
                        middle = (crack_list[i-1].location + crack.location)/2
                        crack.x_l = max(middle, crack.x_l)
                        crack_list[i-1].x_r = min(middle, crack_list[i-1].x_r)
                elif method == "min":
                    if i > 0:
                        left_peak_index = crack_list[i-1].index
                        right_peak_index = crack.index
                        left_valley = strain[left_peak_index:right_peak_index]
                        min_index = np.argmin(left_valley) + left_peak_index
                        crack.x_l = max(x[min_index], crack.x_l)
                        crack_list[i-1].x_r = min(x[min_index], crack_list[i-1].x_r)
                elif method == "threshold":
                    left_peak_index = crack_list[i-1].index if i > 1 else 0
                    right_peak_index = crack.index[i+1] if i < len(x) - 1 else len(len(x) - 1)
                    left_valley = strain[left_peak_index:crack.index+1].reverse()
                    right_valley = strain[crack.index:right_peak_index+1]
                    l_index = self._first_index_leq_threshold(left_valley, value)
                    r_index = self._first_index_leq_threshold(right_valley, value)
                    if l_index is not None:
                        crack.x_l = x[crack.index - l_index]
                    if r_index is not None:
                        crack.x_r = x[crack.index + r_index]
                elif method == "length":
                    crack.x_l = max(crack.location - value, crack.x_l)
                    crack.x_r = min(crack.location + value, crack.x_r)
                else:
                    raise ValueError("No such option '{}' known for `method`.".format(method))
        return crack_list