public static SVMProblem Convert(svm_problem x)
{
double[] y_array = new double[x.l];
Marshal.Copy(x.y, y_array, 0, y_array.Length);
List<SVMNode[]> x_array = new List<SVMNode[]>();
IntPtr i_ptr_x = x.x;
for (int i = 0; i < x.l; i++)
{
IntPtr ptr_nodes = (IntPtr)Marshal.PtrToStructure(i_ptr_x, typeof(IntPtr));
SVMNode[] nodes = SVMNode.Convert(ptr_nodes);
x_array.Add(nodes);
i_ptr_x = IntPtr.Add(i_ptr_x, Marshal.SizeOf(typeof(IntPtr)));
}
SVMProblem y = new SVMProblem();
for (int i = 0; i < x.l; i++)
{
y.Add(x_array[i], y_array[i]);
}
return y;
}
public static IntPtr Allocate(SVMProblem x)
{
if (x == null || x.X == null || x.Y == null || x.Length < 1)
{
return IntPtr.Zero;
}
svm_problem y = new svm_problem();
y.l = x.Length;
// Allocate problem.y
y.y = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(double)) * x.Y.Count);
Marshal.Copy(x.Y.ToArray(), 0, y.y, x.Y.Count);
// Allocate problem.x
y.x = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(IntPtr)) * x.X.Count);
IntPtr i_ptr_x = y.x;
for (int i = 0; i < x.X.Count; i++)
{
// Prepare each node array
// 1) All nodes containing zero value is removed
// 2) A node which index is -1 is added to the end
List<SVMNode> temp = x.X[i].Where(a => a.Value != 0).ToList();
temp.Add(new SVMNode(-1, 0));
SVMNode[] nodes = temp.ToArray();
// Allocate node array
IntPtr ptr_nodes = SVMNode.Allocate(nodes);
Marshal.StructureToPtr(ptr_nodes, i_ptr_x, true);
i_ptr_x = IntPtr.Add(i_ptr_x, Marshal.SizeOf(typeof(IntPtr)));
}
// Allocate the problem
int size = Marshal.SizeOf(y);
IntPtr ptr = Marshal.AllocHGlobal(size);
Marshal.StructureToPtr(y, ptr, true);
return ptr;
}
public static void Free(svm_problem x)
{
Marshal.FreeHGlobal(x.y);
x.y = IntPtr.Zero;
IntPtr i_ptr_x = x.x;
for (int i = 0; i < x.l; i++)
{
IntPtr ptr_nodes = (IntPtr)Marshal.PtrToStructure(i_ptr_x, typeof(IntPtr));
SVMNode.Free(ptr_nodes);
i_ptr_x = IntPtr.Add(i_ptr_x, Marshal.SizeOf(typeof(IntPtr)));
}
Marshal.FreeHGlobal(x.x);
x.x = IntPtr.Zero;
}