Add module docstrings Fix #7 (#38)

* init docstrings

* Add some more context

---------

Co-authored-by: Florian Rupprecht <33600480+nx10@users.noreply.github.com>

Author: tamsinrogers

rbc_qc_metrics_guide.md

@@ -53,12 +53,12 @@ import numpy as np
 def calculate_FD_J_from_rms(rms_file):
     """
     Calculate FD-Jenkinson from MCFLIRT *_rel.rms output.
-    
+
     Parameters
     ----------
     rms_file : str
         Path to *_rel.rms file from MCFLIRT
-    
+
     Returns
     -------
     fdj : np.ndarray
@@ -82,29 +82,29 @@ import numpy as np
 def calculate_FD_P(motion_params_file):
     """
     Calculate FD-Power from 6-parameter motion file.
-    
+
     Parameters
     ----------
     motion_params_file : str
         Path to motion parameters file (6 columns: 3 rotation, 3 translation)
         Format: [rot_x, rot_y, rot_z, trans_x, trans_y, trans_z] per row
-    
+
     Returns
     -------
     fd : np.ndarray
         Framewise displacement array
     """
     motion_params = np.genfromtxt(motion_params_file).T
-    
+
     # Rotations (first 3 params) - convert to mm using 50mm sphere radius
     rotations = np.transpose(np.abs(np.diff(motion_params[0:3, :])))
     # Translations (last 3 params)
     translations = np.transpose(np.abs(np.diff(motion_params[3:6, :])))
-    
+
     # FD = sum of translations + (50mm * pi/180) * sum of rotations
     fd = np.sum(translations, axis=1) + (50 * np.pi / 180) * np.sum(rotations, axis=1)
     fd = np.insert(fd, 0, 0)  # Prepend 0 for first volume
-    
+
     return fd
 ```
 
@@ -118,12 +118,12 @@ import numpy as np
 def calculate_rms_motion(motion_params_file):
     """
     Calculate RMS of translation parameters.
-    
+
     Parameters
     ----------
     motion_params_file : str
         Path to motion parameters (6 columns)
-    
+
     Returns
     -------
     mean_rms : float
@@ -132,10 +132,10 @@ def calculate_rms_motion(motion_params_file):
         Maximum RMS motion
     """
     mot = np.genfromtxt(motion_params_file).T
-    
+
     # RMS of translation parameters (columns 3, 4, 5 for x, y, z translation)
     rms = np.sqrt(mot[3]**2 + mot[4]**2 + mot[5]**2)
-    
+
     return np.mean(rms), np.max(rms)
 ```
 
@@ -156,14 +156,14 @@ import nibabel as nib
 def calculate_DVARS(func_file, mask_file):
     """
     Calculate DVARS (temporal derivative of RMS variance).
-    
+
     Parameters
     ----------
     func_file : str
         Path to 4D functional image
     mask_file : str
         Path to brain mask
-    
+
     Returns
     -------
     dvars : np.ndarray
@@ -173,22 +173,22 @@ def calculate_DVARS(func_file, mask_file):
     """
     func_data = nib.load(func_file).get_fdata().astype(np.float32)
     mask_data = nib.load(mask_file).get_fdata().astype(bool)
-    
+
     # Temporal difference (derivative)
     diff_data = np.diff(func_data, axis=3)
-    
+
     # Square of differences
     squared_diff = np.square(diff_data)
-    
+
     # Apply mask
     masked_data = squared_diff[mask_data]
-    
+
     # RMS across voxels for each timepoint
     dvars = np.sqrt(np.mean(masked_data, axis=0))
-    
+
     # Prepend 0 for first volume
     dvars = np.insert(dvars, 0, 0)
-    
+
     return dvars, np.mean(dvars)
 ```
 
@@ -207,33 +207,33 @@ import numpy as np
 def calculate_motion_dvars_correlation(dvars_file, fdj_file):
     """
     Calculate correlation between DVARS and FD-Jenkinson.
-    
+
     Note: DVARS has N-1 values (no derivative for first volume),
     so we correlate with FD[1:] (skipping first FD value).
-    
+
     Parameters
     ----------
     dvars_file : str
         Path to DVARS 1D file
     fdj_file : str
         Path to FD-Jenkinson 1D file
-    
+
     Returns
     -------
     correlation : float
         Pearson correlation coefficient
     """
     dvars = np.loadtxt(dvars_file)
     fdj = np.loadtxt(fdj_file)
-    
+
     # DVARS is 1 shorter than FD (or both have leading 0)
     # If both have leading 0, skip it
     if len(dvars) == len(fdj):
         dvars = dvars[1:]
         fdj = fdj[1:]
     elif len(dvars) == len(fdj) - 1:
         fdj = fdj[1:]
-    
+
     return np.corrcoef(dvars, fdj)[0, 1]
 ```
 
@@ -261,21 +261,21 @@ import nibabel as nib
 def dice_coefficient(mask1_file, mask2_file):
     """
     Calculate Dice coefficient between two binary masks.
-    
+
     DC = 2|A ∩ B| / (|A| + |B|)
-    
+
     Range: 0 (no overlap) to 1 (perfect overlap)
     """
     mask1 = nib.load(mask1_file).get_fdata().astype(bool)
     mask2 = nib.load(mask2_file).get_fdata().astype(bool)
-    
+
     intersection = np.count_nonzero(mask1 & mask2)
     size1 = np.count_nonzero(mask1)
     size2 = np.count_nonzero(mask2)
-    
+
     if size1 + size2 == 0:
         return 0.0
-    
+
     return 2.0 * intersection / (size1 + size2)
 ```
 
@@ -285,20 +285,20 @@ def dice_coefficient(mask1_file, mask2_file):
 def jaccard_coefficient(mask1_file, mask2_file):
     """
     Calculate Jaccard coefficient between two binary masks.
-    
+
     JC = |A ∩ B| / |A ∪ B|
-    
+
     Range: 0 (no overlap) to 1 (perfect overlap)
     """
     mask1 = nib.load(mask1_file).get_fdata().astype(bool)
     mask2 = nib.load(mask2_file).get_fdata().astype(bool)
-    
+
     intersection = np.count_nonzero(mask1 & mask2)
     union = np.count_nonzero(mask1 | mask2)
-    
+
     if union == 0:
         return 0.0
-    
+
     return intersection / union
 ```
 
@@ -311,7 +311,7 @@ def cross_correlation(mask1_file, mask2_file):
     """
     mask1 = nib.load(mask1_file).get_fdata().astype(bool).flatten()
     mask2 = nib.load(mask2_file).get_fdata().astype(bool).flatten()
-    
+
     return np.corrcoef(mask1, mask2)[0, 1]
 ```
 
@@ -321,18 +321,18 @@ def cross_correlation(mask1_file, mask2_file):
 def coverage(mask1_file, mask2_file):
     """
     Calculate coverage: intersection / smaller mask.
-    
+
     Measures how much of the smaller mask is covered by the overlap.
     """
     mask1 = nib.load(mask1_file).get_fdata().astype(bool)
     mask2 = nib.load(mask2_file).get_fdata().astype(bool)
-    
+
     intersection = np.count_nonzero(mask1 & mask2)
     smaller_size = min(np.count_nonzero(mask1), np.count_nonzero(mask2))
-    
+
     if smaller_size == 0:
         return 0.0
-    
+
     return intersection / smaller_size
 ```
 
@@ -348,7 +348,7 @@ Number of volumes flagged for censoring based on motion/DVARS thresholds.
 def count_censored_volumes(fd, dvars, fd_threshold=0.2, dvars_threshold=None):
     """
     Count volumes exceeding motion thresholds.
-    
+
     Parameters
     ----------
     fd : np.ndarray
@@ -359,7 +359,7 @@ def count_censored_volumes(fd, dvars, fd_threshold=0.2, dvars_threshold=None):
         FD threshold (RBC uses 0.2 mm)
     dvars_threshold : float, optional
         DVARS threshold
-    
+
     Returns
     -------
     n_censored : int
@@ -368,10 +368,10 @@ def count_censored_volumes(fd, dvars, fd_threshold=0.2, dvars_threshold=None):
         Indices of censored volumes
     """
     censor_mask = fd > fd_threshold
-    
+
     if dvars_threshold is not None:
         censor_mask |= dvars > dvars_threshold
-    
+
     return np.sum(censor_mask), np.where(censor_mask)[0].tolist()
 ```
 
@@ -407,7 +407,7 @@ def generate_xcp_qc(
 ):
     """
     Generate XCP-style QC metrics TSV.
-    
+
     Returns
     -------
     qc_dict : dict
@@ -416,46 +416,46 @@ def generate_xcp_qc(
     # Motion metrics
     fdj = np.loadtxt(fd_jenkinson_file)
     mean_fd = np.mean(fdj)
-    
+
     mot = np.genfromtxt(motion_params_file).T
     rms = np.sqrt(mot[3]**2 + mot[4]**2 + mot[5]**2)
-    
+
     # DVARS
     dvars_init = np.loadtxt(dvars_before_file)
     dvars_final = np.loadtxt(dvars_after_file)
-    
+
     # Motion-DVARS correlation
     def dvcorr(dvars, fd):
         if len(dvars) == len(fd):
             return np.corrcoef(dvars[1:], fd[1:])[0, 1]
         return np.corrcoef(dvars, fd[1:])[0, 1]
-    
+
     # Registration metrics
     def load_mask(f):
         return nib.load(f).get_fdata().astype(bool)
-    
+
     def dice(m1, m2):
         inter = np.count_nonzero(m1 & m2)
         return 2.0 * inter / (np.count_nonzero(m1) + np.count_nonzero(m2))
-    
+
     def jaccard(m1, m2):
         return np.count_nonzero(m1 & m2) / np.count_nonzero(m1 | m2)
-    
+
     def crosscorr(m1, m2):
         return np.corrcoef(m1.flatten(), m2.flatten())[0, 1]
-    
+
     def coverage(m1, m2):
         inter = np.count_nonzero(m1 & m2)
         return inter / min(np.count_nonzero(m1), np.count_nonzero(m2))
-    
+
     # Load masks
     coreg_m1, coreg_m2 = load_mask(bold2t1w_mask), load_mask(t1w_mask)
     norm_m1, norm_m2 = load_mask(bold2template_mask), load_mask(template_mask)
-    
+
     # Volume counts
     orig_nvols = nib.load(original_func).shape[3]
     final_nvols = nib.load(final_func).shape[3]
-    
+
     return {
         'sub': sub, 'ses': ses, 'task': task, 'run': run,
         'desc': desc, 'regressors': regressors, 'space': space,
@@ -496,22 +496,22 @@ From the RBC paper (Shafiei et al., Neuron 2025):
 def passes_rbc_qc(qc_dict, fd_timeseries):
     """
     Apply RBC recommended QC thresholds.
-    
+
     Parameters
     ----------
     qc_dict : dict
         Output from generate_xcp_qc
     fd_timeseries : np.ndarray
         Full FD timeseries (for median calculation)
-    
+
     Returns
     -------
     passes : bool
         True if scan passes QC
     """
     median_fd = np.median(fd_timeseries)
     norm_cc = qc_dict['normCrossCorr']
-    
+
     return (median_fd <= 0.2) and (norm_cc >= 0.8)
 ```