biomomentum 0.1.6

Mach-1 Analysis Functions

© Biomomentum Inc - All rights reserved

Biomomentum-functions

This repository contains multiple python scripts used for data analysis in mechanical testing with mach-1 testers from Biomomentum. To use this library, it recommended to use conda environments.

Installation

1. Install Anaconda on your computer.
2. Open Anaconda Powershell Prompt by searching in the taskbar.
3. Create a new environment using the following command on an Anaconda Powershell Prompt (use python 3.11 for most stable release):

conda create --name env python=3.11

3. From the /dist directory of this repository, download the WHL file
4. Activate the newly created environment:

conda activate env

5. Install directly from PIP:

pip install "biomomentum"

6. Import the library into a Python script or notebook:

Import biomomentum

Testing

A jupyter notebook is provided for testing some functions. Follow these steps to try out the notebook on your computer.

1. Open Anaconda Powershell Prompt by searching in the taskbar.
2. Activate the newly created environment:

conda activate env

3. Install jupyter package in the created environment using

conda install jupyter

4. Install matplotlib package in the created environment using

conda install matplotlib

5. Download and install VsCode
6. On the left tab of the software go to extensions and download Python and Jupyter.
7. Download the folder \examples to test the library.

Documentation

The following section presents each function incorporated into the biomomentum Python library.

Utils

sorted_alphanumeric

def sorted_alphanumeric(files) -> list

Sorts alpha numerically files from directory.

Arguments:

• files list - Files from directory to sort.

Returns:

• list - Files from directory to sort.

get_super

def get_super(x) -> str

Insert super script char on string

Arguments:

• x str - Character to super script.

Returns:

• str - Char in super script format.

inDict

def inDict(dict, key) -> Bool

Checks if key is in dictionary.

Arguments:

• dict Dict - Dictionary to check keys.
• key str - Key to check if is in dictionary.

Returns:

• Bool - True if key is in dictionary, false otherwise.

select_data_file

def select_data_file(file_extension = ".txt") -> str

Function that brings a pop up prompt to select the mach-1 file or MAP file.

Arguments:

• file_extension str - File extention from file either .txt (Mach-1 files) or .map (MAP files).

Returns:

• filename str - Directory of the selected file.

select_data_file_dir

def select_data_file_dir(keyword = None, read_MAP = False) -> List

Function that brings a pop up prompt to select a folder contaning multiple mach-1 files or MAP files.

Arguments:

• keyword str - String Name of group of mach-1 files to load in folder.
• read_MAP Bool - Bool to indicate whether to select mach_1 files or MAP files.
  Returns:
• files list - Files of the mach-1 from the folder or MAP files.

stats

ResidualStandardError

def ResidualStandardError(x, xfit, predictors) -> float

Insert super script char on string

Arguments:

• x np.array - Independent variable values (assumed to be error-free).
• xfit np.array - Signal fit of xfit.
• predictor int - Number of predictors of the function.

Returns:

• ser float - Standard residual error.

rsquared

def rsquared(Y, mse, poly_order) -> float

Extracts statistical R-squared.

Arguments:

• Y np.array - Signal Fitted .
• mse np.array - Mean Squared Error of the fit.
• poly_order int - Number of predictors of the function.

Returns:

• Rsq_adj int - Adjusted R-squared.

interpolation

linear_least_square

def linear_least_square(x,y)

Least square algorithm.

Arguments:

• x np.array - independent variable (data units).
• y np.array - dependent variable (data units).

Returns:

• A np.array - Parameters of linear model (A[0] slope, A[1] intercept).
• curveFit np.array - Linear fit.
• Rsq_adj float - Adjusted R-squared.

interpolateMAP

def interpolateMAP(subSurfaces, interpolate_to_bounds = False, smooth_data = False, threshold = 4, keyword = "")

Function to apply 2D linear interpolation into the data.

Arguments:

• subSurfaces dict - Dictionary of all the surfaces identified in the MAP file.
• threshold float - threshold standard deviation to control smoothing.
• interpolate_to_bounds bool - Flag to indicate whether to extrapolate values to surface bound.
• threshold float - threshold standard deviation to control smoothing.
• keyword str - Name given to the measurements in the MAP file.

Returns:

• QP_2D list of np.array - List of 2D array of the interpolated values into the subSurface.
• triangles list of scipy.Delaunay - List of Triangles used for the interpolation (see Delaunay).
• grid_X list of np.array - List of 2D array of the X values used to construct the interpolation.
• grid_Y list of np.array - List of 2D array of the Y values used to construct the interpolation.

smoothMAP

def smoothMAP(QP, triangles, threshold)

Function to smooth data for interpolation.

Arguments:

• QP np.array - independent variable (data units).
• triangles list[list] - list of lists, each sublist contains the indices of neighbors for each data point.
• threshold np.array - threshold standard deviation to control smoothing.

Returns:

• smoothed_map np.array - Smoothed data.

ios

read_mach_1_file

def read_mach_1_file(file_path: Union[str, Path], read_data: bool = True, data_headers: Optional[List[str]] = None, show_progress: bool = True) -> Dict[str, Any]

Parse a Mach-1 Motion .txt file into a nested dictionary structure.

Arguments:

• file_path str - .txt file name generated by Mach-1 Motion .
• read_data int - Integer indicating if the numerical data in the Mach-1 .txt file should be read. Default value is 1. 0: Read only the infos.
• data_headers list - List of specific data headers to load.
• show_progress bool - Flag to show progress bar on command prompt.

Returns:

• result dict - A mapping from function instance keys to a dictionary containing:
  • <INFO>: core info key-values1
  • <FunctionName>: metadata for each function
  • <DATA>: parsed measurement data (numpy arrays)

read_mach_1_files

def read_mach_1_files(sources: Union[str, Path, List[Tuple[Path, str]]], read_data: bool = True, data_headers: Optional[List[str]] = None, pattern: str = "*.txt", show_progress: bool = True, use_multiprocessing: bool = False) -> Tuple[Dict[str, Any], Path]

Read Mach-1 .txt files into a dictionary using the refactored reader.

Arguments:

• read_data int - Integer indicating if the numerical data in the Mach-1 .txt file should be read. Default value is 1. 0: Read only the infos.
• data_headers List - List of specific data headers to load.
• show_progress Bool - Flag to show progress bar on command prompt.
• use_multiprocessing Bool - Flag to indicate whether to use multiprocessing to load mach-1 files.

Returns:

• Tuple:
  • Dict mapping each key to its parsed content.
  • Path of the processed directory (parent of first file).

get_subSurfaces

def get_subSurfaces(MAP_file, keyword = "", scanFlag = False) -> dict

Function to separate surfaces from MAP in dictionary.

Arguments:

• MAP_file str - Map file directory.
• keyword str - Name given to the measurements in the MAP file.
• scanFlag bool - Indicate whether MAP file contains scan data

Returns:

• subSurfaces dict - Dictionary of all the surfaces identified in the MAP file.

analysis_static

compliance_correction

def compliance_correction(displacement, load, criteria = 1, interval = None) -> float

Extracts compliance correction factor for compression tests in mach-1.

Arguments:

• displacement np.array - Displacement of sample in mm.
• load np.array - Load of sample in N.
• criteria float - Criteria to select data.
• interval list - Interval to extract correction factor.

Returns:

• correction_factor float - Correction for compliance.

HayesElasticModel

def HayesElasticModel(posZ, loadZ, gf_flag, maxStrain, R, v, Rsq_req, sampleThickness = None, origin_set=False, eqModulus=False, spherical_indenter=False)

Extracts Elastic Properties from Indentation.

Arguments:

• posZ np.array - Array Z-position (mm).
• loadZ np.array - Array Z-load (gf or N).
• gf_flag Bool - Indicate whether loadZ units is gf.
• maxStrain float - Radius of indenter in mm.
• R flaot - Poisson's ratio.
• v float - Interval to extract correction factor.
• Rsq_req float - Required fit R square value (usually 0.95).
• sampleThickness float - Sample thickness in mm.
• origin_set bool - Indicate whether signal starts at origin.
• eqModulus bool - Indicate whether signal only fits 2 points.
• spherical_indenter bool - Indicate wheter to use cylinder Hayes model or spherical model.

Returns:

• G float - Indentation Shear Modulus in MPa.
• E float - Indentation Elastic Modulus in MPa.
• Fit np.array - Fit for posZ and loadZ using Hayes spherical model 1972.
• Rsq_adj float - Adjusted R-squared for the fit.

relaxation_constant

def relaxation_constant(data, time, startIdx) -> float

Extracts Relaxation Constant from time data.

Arguments:

• data np.array - Data to extract tau.
• time np.array - Time (s).
• startIdx int - Index to indicate where to start the analysis.

Returns:

• tau float - Time constant.

stressrelaxation_fit

def stressrelaxation_fit(t, sz, r0, e0, vm, t0in = None, filemat = None

Function to fit stress relaxation curves and extract mechanical properties.

Arguments:

• t np.array - Data array (s).
• sz np.array - Stress array (MPa).
• r0 Bool - Disk radius (mm).
• e0 float - Disk stress.
• vm flaot - Poisson's ratio.
• t0in float - Compression time (s).
• filemat float - Matlab file (sveff_tab.mat).

Returns:

• szfit np.array - Stress array fit (MPa).
• ef float - Elastic Fibril Modulus (MPa).
• k0 float - Hydraulic permeability (mm2/MPa.s).
• e33 float - Elastic Equilibrium Modulus (MPa).
• t0 float - Compression time (s).
• S11 float - Elastic Modulus S11 (MPa).
• szequ float - Equilibrium stress (MPa).
• K float - Coefficient (MPa.s).
• tau float - Time constant (s).
• em float - Elastic Modulus of isotropic matrix (MPa).
• nm float - Poisson coefficient of isotropic matrix.
• mse float - Mean quadratic error .

get_cartilage_index

def get_cartilage_index(Fz, Time) -> np.array

Function to extract cartilage index from signal

Arguments:

• Fz np.array - Normal force from automatic thickness indentation.
• Time np.array - Time (s).

Returns:

• index_interest_mean np.array - Begin and end of cartilage layer of surface.

analysis_dynamic

FitSinusoid

def FitSinusoid(time, freq, data_1, data_2 = None, method = "trf", lossType = "soft_l1", fscale = 0.001, trim_data = False)

Sinusoid fit on data using least-squares and extract dynamic modulus.

Arguments:

• time np.array - time vector (s).
• freq float - frequency guess (Hz).
• data_1 np.array - data vector (data units) .
• data_2 np.array - data vector (data units) to sync with data_1 (None by default).
• method np.array - method for the least-squares (least_squares).
• lossType np.array - loss for the method applied (least_squares).
• fscale np.array - weight for the loss function (least_squares).
• trim_data bool - bool to indicate whether to trim the data or not.

Returns:

• Params structure - If data_2 is not given then.
  • Params[0] float - Sin offset of data_1.
  • Params[1] float - Sin amplitude of data_1.
  • Params[2] float - Sin frequency of data_1.
  • Params[3] float - Sin phase of data_1.
• Params structure - If data_2 is given then.
  • Params[2] float - Sin frequency of data_1 and data_2.
  • Params[4] float - Sin offset of data_2.
  • Params[5] float - Sin amplitude of data_2.
  • Params[6] float - Sin phase of data_2.
• data_sin np.array - Sin fit into data_1.
• data_sin_2 np.array - Sin fit into data_2 (if passed in arguments).
• data_extra np.array - Data trimmed if flag passed (for plotting) for data_1.
• data_extra_2 np.array - Data trimmed if flag passed (for plotting) for data_2 (if passed in arguments).
• ser_data float - Residual standard error of the fit for data_1.
• ser_data_2 float - Residual standard error of the fit for data_2 (if passed in arguments).