io/adios2: support scalar attributes

Author: germasch

src/kg/include/kg/io/Engine.inl

@@ -93,7 +93,7 @@ inline void Engine::putVariable(const T* data, const Mode launch,
 template <typename T>
 inline void Engine::putAttribute(const T& datum)
 {
-  file_.putAttribute(prefix(), &datum, 1);
+  file_.putAttribute(prefix(), datum);
 }
 
 template <typename T>

src/kg/include/kg/io/File.h

@@ -41,6 +41,9 @@ class File
   template <typename T>
   void getAttribute(const std::string& name, T* data);
 
+  template <typename T>
+  void putAttribute(const std::string& name, const T& datum);
+
   template <typename T>
   void putAttribute(const std::string& name, const T* data, size_t size);
 

src/kg/include/kg/io/File.inl

@@ -61,6 +61,14 @@ inline void File::getAttribute(const std::string& name, T* data)
   impl_->getAttribute(name, dataVar);
 }
 
+template <typename T>
+inline void File::putAttribute(const std::string& name, const T& datum)
+{
+  assert(impl_);
+  FileBase::Type datumVar = datum;
+  impl_->putAttribute(name, datumVar);
+}
+
 template <typename T>
 inline void File::putAttribute(const std::string& name, const T* data,
                                size_t size)

src/kg/include/kg/io/FileAdios2.h

@@ -35,6 +35,7 @@ class FileAdios2 : public FileBase
   Dims shapeVariable(const std::string& name) const override;
 
   void getAttribute(const std::string& name, TypePointer data) override;
+  void putAttribute(const std::string& name, const Type& datum) override;
   void putAttribute(const std::string& name, TypeConstPointer data,
                     size_t size) override;
   size_t sizeAttribute(const std::string& name) const override;
@@ -44,6 +45,7 @@ class FileAdios2 : public FileBase
   struct GetVariable;
   struct GetAttribute;
   struct PutAttribute;
+  struct PutAttributeScalar;
 
   template <typename T>
   void putVariable(const std::string& name, const T* data, Mode launch,
@@ -57,6 +59,9 @@ class FileAdios2 : public FileBase
   template <typename T>
   void getAttribute(const std::string& name, T* data);
 
+  template <typename T>
+  void putAttribute(const std::string& name, const T& datum);
+
   template <typename T>
   void putAttribute(const std::string& name, const T* data, size_t size);
 

src/kg/include/kg/io/FileAdios2.inl

@@ -21,6 +21,7 @@ inline FileAdios2::FileAdios2(adios2::ADIOS& ad, const std::string& name,
     io_name_ = io_name;
   }
   io_ = ad.DeclareIO(io_name_);
+  // io_.SetEngine("BP4");
   adios2::Mode adios2_mode;
   if (mode == Mode::Read) {
     adios2_mode = adios2::Mode::Read;
@@ -179,6 +180,21 @@ inline Dims FileAdios2::shapeVariable(const std::string& name) const
   std::abort();
 }
 
+template <typename T>
+inline void FileAdios2::putAttribute(const std::string& name, const T& datum)
+{
+  // if (mpiRank() != 0) { // FIXME, should we do this?
+  //   return;
+  // }
+  auto attr = io_.InquireAttribute<T>(name);
+  if (attr) {
+    mprintf("attr '%s' already exists -- ignoring it!\n", name.c_str());
+  } else {
+    // FIXME? we're never using "single value", just an array of size 1
+    io_.DefineAttribute<T>(name, datum);
+  }
+}
+
 template <typename T>
 inline void FileAdios2::putAttribute(const std::string& name, const T* data,
                                      size_t size)
@@ -224,6 +240,27 @@ inline void FileAdios2::getAttribute(const std::string& name, TypePointer data)
   mpark::visit(GetAttribute{*this, name}, data);
 }
 
+struct FileAdios2::PutAttributeScalar
+{
+  PutAttributeScalar(FileAdios2& self, const std::string& name)
+    : self{self}, name{name}
+  {}
+
+  template <typename T>
+  void operator()(const T& datum)
+  {
+    self.putAttribute(name, datum);
+  }
+
+  FileAdios2& self;
+  const std::string& name;
+};
+
+inline void FileAdios2::putAttribute(const std::string& name, const Type& datum)
+{
+  mpark::visit(PutAttributeScalar{*this, name}, datum);
+}
+
 struct FileAdios2::PutAttribute
 {
   PutAttribute(FileAdios2& self, const std::string& name, size_t size)

src/kg/include/kg/io/FileBase.h

@@ -14,6 +14,8 @@ namespace io
 class FileBase
 {
 public:
+  using Type = mpark::variant<int, unsigned int, unsigned long,
+                              unsigned long long, float, double, std::string>;
   using TypePointer =
     mpark::variant<int*, unsigned int*, unsigned long*, unsigned long long*,
                    float*, double*, std::string*>;
@@ -41,6 +43,7 @@ class FileBase
   virtual Dims shapeVariable(const std::string& name) const = 0;
 
   virtual void getAttribute(const std::string& name, TypePointer data) = 0;
+  virtual void putAttribute(const std::string& name, const Type& datum) = 0;
   virtual void putAttribute(const std::string& name, TypeConstPointer data,
                             size_t size) = 0;
   virtual size_t sizeAttribute(const std::string& name) const = 0;

src/kg/testing/io/TestIOAdios2.cxx

@@ -76,6 +76,8 @@ TEST(IOAdios2, FilePutGetAttribute)
     file.beginStep(kg::io::StepMode::Append);
     auto dbl = std::vector<double>{1., 2., 3., 4., 5.};
     file.putAttribute("attr_dbl", dbl.data(), dbl.size());
+    double val = 99.;
+    file.putAttribute("attr_dbl_scalar", val);
     file.endStep();
   }
   {
@@ -84,7 +86,10 @@ TEST(IOAdios2, FilePutGetAttribute)
     auto size = file.sizeAttribute("attr_dbl");
     auto dbl = std::vector<double>(size);
     file.getAttribute("attr_dbl", dbl.data());
+    double val;
+    file.getAttribute("attr_dbl_scalar", &val);
     EXPECT_EQ(dbl, (std::vector<double>{1., 2., 3., 4., 5.}));
+    EXPECT_EQ(val, 99.);
     file.endStep();
   }
 }