public static unsafe extern int MPI_Address(IntPtr location, out MPI_Aint address);
public static unsafe extern int MPI_Type_extent(MPI_Datatype datatype, out MPI_Aint extent);
public static unsafe extern int MPI_Type_struct(int count, int[] array_of_blocklengths, MPI_Aint[] array_of_displacements, MPI_Datatype[] array_of_types, out MPI_Datatype newtype);
public static unsafe extern int MPI_Type_hindexed(int count, int[] array_of_blocklengths, MPI_Aint[] array_of_displacements, MPI_Datatype oldtype, out MPI_Datatype newtype);
public static unsafe extern int MPI_Type_hvector(int count, int blocklength, MPI_Aint stride, MPI_Datatype oldtype, out MPI_Datatype newtype);
public static extern unsafe int MPI_Alloc_mem(MPI_Aint size, MPI_Info info, out IntPtr baseptr);
/// <summary>
/// Builds a new MPI datatype by using reflection on the given type.
/// </summary>
private static MPI_Datatype BuildDatatype(Type type)
{
// Try to build an MPI datatype using reflection, and return that value.
FieldInfo[] fields = type.GetFields(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance);
int[] blocklens = new int[fields.Length];
MPI_Aint[] indices = new MPI_Aint[fields.Length];
MPI_Datatype[] types = new MPI_Datatype[fields.Length];
int actualLength = 0;
// Walk the fields of the data structure, computing offsets and types
// for the MPI datatype
foreach (FieldInfo field in fields)
{
// Only include non-static, serialized fields
if (!field.IsStatic && !field.IsNotSerialized)
{
Type fieldType = field.FieldType; // The type stored in the field
int fieldLength = 1; // Number of elements in this field. > 1 only for "fixed" fields
// Handle "fixed" arrays in structures, such as:
//
// struct Dimensions
// {
// public unsafe fixed float values[11];
// }
//
// .NET 2.0 uses a synthesized type whose name contains "__FixedBuffer" for this
// field. The type itself has size = sizeof(float)*11, and contains a field
// named "FixedElementType", whose type is "float".
if (fieldType.Name.Contains("__FixedBuffer"))
{
// Dig out the inner field
FieldInfo innerField = fieldType.GetFields()[0];
// Determine the number of elements
fieldLength = Marshal.SizeOf(fieldType) / Marshal.SizeOf(innerField.FieldType);
// Pull out the type of the fixed array
fieldType = innerField.FieldType;
}
// Find the field's MPI datatype
MPI_Datatype fieldDatatype = GetDatatype(fieldType);
if (fieldDatatype == Unsafe.MPI_DATATYPE_NULL)
{
// There is no MPI datatype for this field, so we cannot build a
// datatype for this struct. Note this failure and return.
return(Unsafe.MPI_DATATYPE_NULL);
}
// Compute the offset of this field
int fieldOffset = (int)Marshal.OffsetOf(type, field.Name);
// Record this field
blocklens[actualLength] = fieldLength;
indices[actualLength] = new IntPtr(fieldOffset);
types[actualLength] = fieldDatatype;
++actualLength;
}
}
// Create the MPI datatype
MPI_Datatype datatype;
unsafe
{
// Build the MPI datatype as a "structure"
int errorCode = Unsafe.MPI_Type_struct(actualLength, blocklens, indices, types, out datatype);
if (errorCode != Unsafe.MPI_SUCCESS)
{
throw Environment.TranslateErrorIntoException(errorCode);
}
// Commit the newly-constructed MPI datatype
errorCode = Unsafe.MPI_Type_commit(ref datatype);
if (errorCode != Unsafe.MPI_SUCCESS)
{
throw Environment.TranslateErrorIntoException(errorCode);
}
}
return(datatype);
}
