Add a sampling info file (Exawind#1387)

* Add a sampling info file

* add doc

* add parsing of info to the amrex particle reader

* tweak doc

* linting

amr-wind/utilities/sampling/Sampling.H

@@ -109,6 +109,9 @@ protected:
      */
     virtual void write_ascii();
 
+    //! Output extra information for certain formats
+    void write_info_file(const std::string& fname);
+
     SamplingContainer& sampling_container() { return *m_scontainer; }
 
 private:

amr-wind/utilities/sampling/Sampling.cpp

@@ -398,6 +398,9 @@ void Sampling::impl_write_native()
             const SamplingContainer::SuperParticleType& p) {
             return p.id() > 0;
         });
+
+    const std::string info_name = name + "/sampling_info";
+    write_info_file(info_name);
 }
 
 void Sampling::write_ascii()
@@ -413,6 +416,32 @@ void Sampling::write_ascii()
 
     const std::string fname = post_dir + "/" + sname + ".txt";
     m_scontainer->WriteAsciiFile(fname);
+
+    const std::string info_name = post_dir + "/" + sname + "_info.txt";
+    write_info_file(info_name);
+}
+
+void Sampling::write_info_file(const std::string& fname)
+{
+    BL_PROFILE("amr-wind::Sampling::write_info_file");
+
+    // Only I/O processor writes the info file
+    if (!amrex::ParallelDescriptor::IOProcessor()) {
+        return;
+    }
+
+    if ((m_out_fmt != "native") && (m_out_fmt != "ascii")) {
+        amrex::Abort(
+            "write_info_file is implemented only for native and ascii formats");
+    }
+
+    std::ofstream fh(fname.c_str(), std::ios::out);
+    if (!fh.good()) {
+        amrex::FileOpenFailed(fname);
+    }
+
+    fh << "time " << m_sim.time().new_time() << std::endl;
+    fh.close();
 }
 
 void Sampling::prepare_netcdf_file()

docs/sphinx/user/inputs_Sampling.rst

@@ -100,7 +100,11 @@ where ``uid`` is the global probe id, ``set_id`` is the label id
 input order), ``probe_id`` is the local probe id to this label,
 ``*co`` are the coordinates of the probe, and the other columns are
 the user requested sampled fields. The same labels are seeing by other
-visualization tools such as ParaView.
+visualization tools such as ParaView. The directory also contains a
+``sampling_info`` file where additional information (e.g., time) is
+stored. This file is automatically parse by the provided particle
+reader tool and the information is stored in a dictionary that is a
+member variable of the class.
 
 Sampling along a line
 ``````````````````````

tools/amrex_particle.py

@@ -46,6 +46,7 @@ def __call__(self):
         """
         if not hasattr(self, "df"):
             self.parse_header()
+            self.parse_info()
             self.load_binary_data()
         return self.df
 
@@ -79,6 +80,14 @@ def parse_header(self):
                         [int(ix) for ix in fh.readline().strip().split()])
                 self.grid_info.append(ginfo)
 
+    def parse_info(self):
+        """Parse the sampling info file"""
+        self.info = {}
+        with open(self.pdir.parent / "sampling_info", 'r') as fh:
+            for line in fh:
+                (key, val) = line.split()
+                self.info[key] = float(val)
+
     def load_binary_data(self):
         """Read binary data into memory"""
         self.real_data = np.empty((self.num_particles,

tools/fcompare_particles.py

@@ -29,8 +29,11 @@ def main():
     assert Path(args.f0).is_dir()
     assert Path(args.f1).is_dir()
 
-    p0df = AmrexParticleFile(Path(args.f0) / "particles")()
-    p1df = AmrexParticleFile(Path(args.f1) / "particles")()
+    p0f = AmrexParticleFile(Path(args.f0) / "particles")
+    p1f = AmrexParticleFile(Path(args.f1) / "particles")
+    p0df = p0f()
+    p1df = p1f()
+    assert np.abs(p0f.info["time"] - p1f.info["time"]) <= args.abs_tol
     assert p0df.shape == p1df.shape
     p0df.sort_values(by=["uid"], inplace=True, kind="stable", ignore_index=True)
     p1df.sort_values(by=["uid"], inplace=True, kind="stable", ignore_index=True)