dg::RealMPIGrid2d< real_type > Struct Template Reference

The simplest implementation of aRealMPITopology2d. More...

Inheritance diagram for dg::RealMPIGrid2d< real_type >:

Public Member Functions
	RealMPIGrid2d (real_type x0, real_type x1, real_type y0, real_type y1, unsigned n, unsigned Nx, unsigned Ny, MPI_Comm comm)
	Equal polynomial coefficients. More...
	RealMPIGrid2d (real_type x0, real_type x1, real_type y0, real_type y1, unsigned n, unsigned Nx, unsigned Ny, bc bcx, bc bcy, MPI_Comm comm)
	Equal polynomial coefficients. More...
	RealMPIGrid2d (RealGrid1d< real_type > gx, RealGrid1d< real_type > gy, MPI_Comm comm)
	Construct a 2d grid as the product of two 1d grids. More...
	RealMPIGrid2d (const aRealMPITopology2d< real_type > &src)
	allow explicit type conversion from any other topology More...
Public Member Functions inherited from dg::aRealMPITopology2d< real_type >
real_type	x0 () const
	Return global x0. More...
real_type	x1 () const
	Return global x1. More...
real_type	y0 () const
	Return global y0. More...
real_type	y1 () const
	Return global y1. More...
real_type	lx () const
	Return global lx. More...
real_type	ly () const
	Return global ly. More...
real_type	hx () const
	Return global hx. More...
real_type	hy () const
	Return global hy. More...
unsigned	n () const
	Return n. More...
unsigned	nx () const
	number of polynomial coefficients in x More...
unsigned	ny () const
	number of polynomial coefficients in y More...
unsigned	Nx () const
	Return the global number of cells. More...
unsigned	Ny () const
	Return the global number of cells. More...
bc	bcx () const
	global x boundary More...
bc	bcy () const
	global y boundary More...
MPI_Comm	communicator () const
	Return mpi cartesian communicator that is used in this grid. More...
const DLT< real_type > &	dltx () const
	discrete legendre transformation in x More...
const DLT< real_type > &	dlty () const
	discrete legendre transformation in y More...
unsigned	size () const
	The total global number of points. More...
unsigned	local_size () const
	The total local number of points. More...
void	display (std::ostream &os=std::cout) const
	Display global and local grid. More...
int	pidOf (real_type x, real_type y) const
	Returns the pid of the process that holds the local grid surrounding the given point. More...
void	multiplyCellNumbers (real_type fx, real_type fy)
	Multiply the number of cells with a given factor. More...
void	set (unsigned new_n, unsigned new_Nx, unsigned new_Ny)
	Set the number of polynomials and cells. More...
void	set (unsigned new_nx, unsigned new_Nx, unsigned new_ny, unsigned new_Ny)
	Set the number of polynomials and cells. More...
bool	local2globalIdx (int localIdx, int PID, int &globalIdx) const
	Map a local index plus the PID to a global vector index. More...
bool	global2localIdx (int globalIdx, int &localIdx, int &PID) const
	Map a global vector index to a local vector Index and the corresponding PID. More...
const RealGrid2d< real_type > &	local () const
	Return a non-MPI grid local for the calling process. More...
const RealGrid2d< real_type > &	global () const
	Return the global non-MPI grid. More...

Additional Inherited Members
Public Types inherited from dg::aRealMPITopology2d< real_type >
using	value_type = real_type
using	host_vector = MPI_Vector< thrust::host_vector< real_type > >
	The host vector type used by host functions like evaluate. More...
using	host_grid = RealMPIGrid2d< real_type >
Protected Member Functions inherited from dg::aRealMPITopology2d< real_type >
	~aRealMPITopology2d ()=default
	disallow deletion through base class pointer More...
	aRealMPITopology2d (RealGrid1d< real_type > gx, RealGrid1d< real_type > gy, MPI_Comm comm)
	Construct a 2d grid as the product of two 1d grids. More...
	aRealMPITopology2d (const aRealMPITopology2d &src)=default
aRealMPITopology2d &	operator= (const aRealMPITopology2d &src)=default
virtual void	do_set (unsigned new_nx, unsigned new_Nx, unsigned new_ny, unsigned new_Ny)=0
	This function has an implementation. More...

Detailed Description

template<class real_type>
struct dg::RealMPIGrid2d< real_type >

The simplest implementation of aRealMPITopology2d.

This code snippet demonstrates how to discretize and compute the norm of a function on a distributed memory system

//define the function to integrate
double function(double x, double y, double amp){
    return amp*exp(x)*exp(y);
}
 
// create a grid of the domain [0,2]x[0,2] with 20 cells in x and y and 3 polynomial coefficients
//... use MPI_Cart_create to create 2d Cartesian communicator
dg::MPIGrid2d g2d( 0, 2, 0, 2, 3, 20, 20, comm2d);
 
// create the Gaussian weights (volume form) for the integration
const dg::MHVec w2d = dg::create::weights( g2d);
 
// our function needs to depend only on x and y so let's fix the amplitude to 2
using namespace std::placeholders; //for _1, _2
auto functor = std::bind( function, _1, _2, 2.);
 
// discretize the function on the grid
const dg::MHVec vec = dg::evaluate( functor, g2d);
 
// multiply and sum the results
double norm = dg::blas2::dot( vec, w2d, vec);
 
// norm is now: (e^4-1)^2

Constructor & Destructor Documentation

RealMPIGrid2d() [1/4]

template<class real_type >

dg::RealMPIGrid2d< real_type >::RealMPIGrid2d ( real_type  x0, real_type  x1, real_type  y0, real_type  y1, unsigned  n, unsigned  Nx, unsigned  Ny, MPI_Comm  comm  )

inline

Equal polynomial coefficients.

Parameters

x0	left boundary in x
x1	right boundary in x
y0	lower boundary in y
y1	upper boundary in y
n	# of polynomial coefficients for both x and y dimension (1<=n<=20)
Nx	# of points in x
Ny	# of points in y
comm	a two-dimensional Cartesian communicator

Note

the paramateres given in the constructor are global parameters

RealMPIGrid2d() [2/4]

template<class real_type >

dg::RealMPIGrid2d< real_type >::RealMPIGrid2d ( real_type  x0, real_type  x1, real_type  y0, real_type  y1, unsigned  n, unsigned  Nx, unsigned  Ny, bc  bcx, bc  bcy, MPI_Comm  comm  )

inline

Equal polynomial coefficients.

Parameters

x0	left boundary in x
x1	right boundary in x
y0	lower boundary in y
y1	upper boundary in y
n	# of polynomial coefficients for both x and y dimension (1<=n<=20)
Nx	# of points in x
Ny	# of points in y
bcx	boundary condition in x
bcy	boundary condition in y
comm	a two-dimensional Cartesian communicator

Note

the paramateres given in the constructor are global parameters

RealMPIGrid2d() [3/4]

template<class real_type >

dg::RealMPIGrid2d< real_type >::RealMPIGrid2d ( RealGrid1d< real_type >  gx, RealGrid1d< real_type >  gy, MPI_Comm  comm  )

inline

Construct a 2d grid as the product of two 1d grids.

dg::Grid2d g2d( {x0,x1,nx,Nx,bcx},{y0,y1,ny,Ny,bcy});

Parameters

gx	a Grid in x - direction
gy	a Grid in y - direction
comm	a two-dimensional Cartesian communicator

Note

the paramateres given in the constructor are global parameters

RealMPIGrid2d() [4/4]

template<class real_type >

dg::RealMPIGrid2d< real_type >::RealMPIGrid2d ( const aRealMPITopology2d< real_type > &  src )

inlineexplicit

allow explicit type conversion from any other topology

---

The documentation for this struct was generated from the following file:

• topology/mpi_grid.h