return double datasets as numpy arrays using numpy.i and safe API

src/pytrexio.i

@@ -46,6 +46,22 @@
 #define TREXIO_HDF5 0
 #define TREXIO_TEXT 0
 */
+
+/* This is an attempt to make SWIG treat double * dset_out, const uint64_t dim_out pattern 
+   as a special case in order to return the NumPy array to Python from C pointer to array
+   provided by trexio_read_safe_[dset_num] function.
+   NOTE: numpy.i is currently not part of SWIG but included in the numpy distribution (under numpy/tools/swig/numpy.i)
+         This means that the interface file have to be provided to SWIG upon compilation either by 
+         copying it to the local working directory or by providing -l/path/to/numpy.i flag upon SWIG compilation
+*/
+%include "numpy.i"
+
+%init %{
+import_array();
+%}
+
+%apply (double* ARGOUT_ARRAY1, int DIM1) {(double * const dset_out, const uint64_t dim_out)};
+
 /* This tells SWIG to treat char ** dset_in pattern as a special case 
    Enables access to trexio_[...]_write_dset_str set of functions directly, i.e.
    by converting input list of strings from Python into char ** of C
@@ -79,7 +95,7 @@
 
 /* [WIP] This is an attempt to make SWIG treat char ** dset_out as a special case 
    In order to return list of string to Python from C-native char ** dset_out,
-   which is modified (but not allocated) within the trexio_[...}read_dset_str function
+   which is modified (but not allocated) within the trexio_[...]_read_dset_str function
 */
 %typemap(in, numinputs=0) char ** dset_out (char * temp) {
   /*temp = (char *) malloc(1028*sizeof(char));*/

src/test.py

@@ -1,5 +1,6 @@
 import os
 import shutil
+#import numpy as np
 
 from pytrexio import *
 
@@ -95,9 +96,26 @@ assert rc==TREXIO_SUCCESS
 for i in range(nucleus_num):
     assert charges2[i]==charges[i]
 
+#charge_numpy = np.zeros(nucleus_num, dtype=np.float64) 
+#print(charge_numpy)
+
+rc, charge_numpy = trexio_read_safe_nucleus_charge(test_file2, 12)
+
+print(charge_numpy)
+print(charge_numpy[11])
+assert rc==TREXIO_SUCCESS
+
+# unsafe call to read_safe should not only have return code = TREXIO_UNSAFE_ARRAY_DIM
+# but also should not return numpy array filled with garbage
+rc, charge_numpy = trexio_read_safe_nucleus_charge(test_file2, 12*5)
+
+#print(charge_numpy)
+assert rc==TREXIO_UNSAFE_ARRAY_DIM
+
 # [WIP]: ideally, the list of strings should be returned as below
 #rc, label_2d = trexio_read_nucleus_label(test_file2, 10)
 # [WIP]: currently only low-level routines (return one long string instead of an array of strings) work
+
 rc, labels_1d = trexio_read_nucleus_label_low(test_file2, 10)
 assert rc==TREXIO_SUCCESS
 
@@ -109,5 +127,13 @@ for i in range(nucleus_num):
 rc = trexio_close(test_file2)
 assert rc==TREXIO_SUCCESS
 
+try:
+    if TEST_TREXIO_BACKEND == TREXIO_HDF5:
+        os.remove(output_filename)
+    elif TEST_TREXIO_BACKEND == TREXIO_TEXT:
+        shutil.rmtree(output_filename)
+except:
+    print (f'No output file {output_filename} has been produced')
+
 #==========================================================#