Add a per process cache to avoid reading the same data multiple time

xsocs/process/fit/peak_fit.py

@@ -187,6 +187,7 @@ class PeakFitter(Thread):
         self.__set_status(self.RUNNING)
 
         pool = multiprocessing.Pool(self.__n_proc)
+
         fit_results = []
         for result in pool.imap(
                 functools.partial(_fit_process,
@@ -256,6 +257,10 @@ class PeakFitter(Thread):
         return results
 
 
+# Per process cache for fit process
+_per_process_cache = None
+
+
 def _fit_process(index,
                  qspace_f,
                  fit_type=FitTypes.GAUSSIAN,
@@ -278,11 +283,17 @@ def _fit_process(index,
     :return: Fit results as a list of results for dim0, dim1 and dim2
     :rtype: List[List[Union[float,bool]]]
     """
-    # Read data from file
-    with QSpaceH5.QSpaceH5(qspace_f) as qspace_h5:
-        axes = qspace_h5.qspace_dimension_values
-        hits = qspace_h5.histo
-        qspace = qspace_h5.qspace_slice(index)
+    global _per_process_cache
+    if _per_process_cache is None:  # Initialize per process cache
+        qspace_h5 = QSpaceH5.QSpaceH5(qspace_f)
+        _per_process_cache = (
+            qspace_h5, qspace_h5.qspace_dimension_values, qspace_h5.histo)
+
+    # Retrieve data/file from cache
+    qspace_h5, axes, hits = _per_process_cache
+
+    # Load qspace
+    qspace = qspace_h5.qspace_slice(index)
 
     # apply Qspace ROI
     if roiIndices is not None: