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doc: Corrections to IFEM rst manual
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Change-Id: I5f7a829b6c06ecf71b159329f815f4d3c9e8cf6a
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@mprobson @evan-charmworks
mprobson authored and evan-charmworks committed Feb 20, 2019
1 parent 0bc6c31 commit 9d7a746
Showing 1 changed file with 72 additions and 71 deletions.
143 changes: 72 additions & 71 deletions doc/ifem/manual.rst
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Original file line number Diff line number Diff line change
Expand Up @@ -117,24 +117,26 @@ IFEM_Solve_shared

::

void IFEM_Solve_shared(ILSI_Solver s,ILSI_Param *p, int fem_mesh, int
fem_entity,int length,int width, IFEM_Matrix_product_c A, void *ptr,
void IFEM_Solve_shared(ILSI_Solver s, ILSI_Param *p, int fem_mesh, int
fem_entity, int length, int width, IFEM_Matrix_product_c A, void *ptr,
const double *b, double *x);

.. code-block:: fortran
subroutine IFEM_Solve_shared(s,p,fem_mesh,fem_entity,length,width,A,ptr,b,x)
subroutine IFEM_Solve_shared(s, p, fem_mesh, fem_entity, length, width, A, ptr, b, x)
external solver subroutine :: s
double precision, intent(inout) :: p(ILSI PARAM)
integer, intent(in) :: fem mesh, fem entity, length,width external matrix-vector product subroutine :: A TYPE(varies), pointer :: ptr
integer, intent(in) :: fem mesh, fem entity, length, width
external matrix-vector product subroutine :: A
TYPE(varies), pointer :: ptr
double precision, intent(in) :: b(width,length)
double precision, intent(inout) :: x(width,length)
This routine solves the linear system :math:`A x = b` for the unknown
vector :math:`x`. s and p give the particular linear solver to use,
and are described in more detail in Section :numref:`sec:solver`.
fem_mesh and fem_entity give the FEM framework mesh (often
FEM_Mesh_default_read()) and entity (often FEM_NODE) with which the
``FEM_Mesh_default_read()``) and entity (often ``FEM_NODE``) with which the
known and unknown vectors are listed.

width gives the number of degrees of freedom (entries in the vector) per
Expand All @@ -157,47 +159,47 @@ and the output values of the solver parameters p will have been written.
::

// C++ Example
int mesh=FEM_Mesh_default_read();
int nNodes=FEM_Mesh_get_length(mesh,FEM_NODE);
int width=3; //A 3D problem
ILSI_Param solverParam;
struct myProblemData myData;
int mesh=FEM_Mesh_default_read();
int nNodes=FEM_Mesh_get_length(mesh,FEM_NODE);
int width=3; //A 3D problem
ILSI_Param solverParam;
struct myProblemData myData;

double *b=new double[nNodes*width];
double *x=new double[nNodes*width];
... prepare solution target b and guess x ...
double *b=new double[nNodes*width];
double *x=new double[nNodes*width];
... prepare solution target b and guess x ...

ILSI_Param_new(&solverParam);
solverParam.maxResidual=1.0e-4;
solverParam.maxIterations=500;
ILSI_Param_new(&solverParam);
solverParam.maxResidual=1.0e-4;
solverParam.maxIterations=500;

IFEM_Solve_shared(IFEM_CG_Solver,&solverParam,
mesh,FEM_NODE, nNodes,width,
myMatrixVectorProduct, &myData, b,x);
IFEM_Solve_shared(IFEM_CG_Solver,&solverParam,
mesh,FEM_NODE,nNodes,width,
myMatrixVectorProduct,&myData,b,x);

.. code-block:: fortran
! F90 Example
include 'ifemf.h'
INTEGER :: mesh, nNodes,width
DOUBLE PRECISION, ALLOCATABLE :: b(:,:), x(:,:)
DOUBLE PRECISION :: solverParam(ILSI_PARAM)
TYPE(myProblemData) :: myData
include 'ifemf.h'
INTEGER :: mesh, nNodes,width
DOUBLE PRECISION, ALLOCATABLE :: b(:,:), x(:,:)
DOUBLE PRECISION :: solverParam(ILSI_PARAM)
TYPE(myProblemData) :: myData
mesh=FEM_Mesh_default_read()
nNodes=FEM_Mesh_get_length(mesh,FEM_NODE)
width=3 ! A 3D problem
mesh=FEM_Mesh_default_read()
nNodes=FEM_Mesh_get_length(mesh,FEM_NODE)
width=3 ! A 3D problem
ALLOCATE(b(width,nNodes), x(width,nNodes))
... prepare solution target b and guess x ..
ALLOCATE(b(width,nNodes), x(width,nNodes))
... prepare solution target b and guess x ..
ILSI_Param_new(&solverParam);
solverParam(1)=1.0e-4;
solverParam(2)=500;
ILSI_Param_new(&solverParam);
solverParam(1)=1.0e-4;
solverParam(2)=500;
IFEM_Solve_shared(IFEM_CG_Solver,solverParam,
mesh,FEM_NODE, nNodes,width,
myMatrixVectorProduct, myData, b,x);
IFEM_Solve_shared(IFEM_CG_Solver,solverParam,
mesh,FEM_NODE,nNodes,width,
myMatrixVectorProduct,myData,b,x);
.. _sec:mvp:

Expand All @@ -210,16 +212,16 @@ subroutine name, but it must take these arguments:

::

void IFEM_Matrix_product(void *ptr,int length,int width, const double
void IFEM_Matrix_product(void *ptr, int length, int width, const double
*src, double *dest);

.. code-block:: fortran
subroutine IFEM_Matrix_product(ptr,length,width,src,dest)
subroutine IFEM_Matrix_product(ptr, length, width, src, dest)
TYPE(varies), pointer :: ptr
integer, intent(in) :: length,width
double precision, intent(in) :: src(width,length)
double precision, intent(out) :: dest(width,length)
integer, intent(in) :: length, width
double precision, intent(in) :: src(width, length)
double precision, intent(out) :: dest(width, length)
The framework calls this user-written routine when it requires a
Expand Down Expand Up @@ -271,11 +273,11 @@ consistent global matrix-vector product.
.. code-block:: fortran
! F90 Example
TYPE(myProblemData)
INTEGER :: nElements
INTEGER, ALLOCATABLE :: conn(2,:)
DOUBLE PRECISION :: k
END TYPE
TYPE(myProblemData)
INTEGER :: nElements
INTEGER, ALLOCATABLE :: conn(2,:)
DOUBLE PRECISION :: k
END TYPE
SUBROUTINE myMatrixVectorProduct(d,nNodes,dofPerNode,src,dest)
include 'ifemf.h'
Expand All @@ -300,15 +302,15 @@ IFEM_Solve_shared_bc

::

void IFEM_Solve_shared_bc(ILSI_Solver s,ILSI_Param *p, int fem_mesh,
int fem_entity,int length,int width, int bcCount, const int *bcDOF,
void IFEM_Solve_shared_bc(ILSI_Solver s, ILSI_Param *p, int fem_mesh,
int fem_entity, int length, int width, int bcCount, const int *bcDOF,
const double *bcValue, IFEM_Matrix_product_c A, void *ptr, const
double *b, double *x);

.. code-block:: fortran
subroutine IFEM_Solve_shared_bc(s,p,
fem_mesh,fem_entity,length,width, bcCount,bcDOF,bcValue, A,ptr,b,x)
subroutine IFEM_Solve_shared_bc(s, p, fem_mesh, fem_entity, length, width,
bcCount, bcDOF, bcValue, A, ptr, b, x)
external solver subroutine :: s
double precision, intent(inout) :: p(ILSI_PARAM)
integer, intent(in) :: fem_mesh, fem_entity, length,width
Expand All @@ -320,7 +322,7 @@ IFEM_Solve_shared_bc
double precision, intent(in) :: b(width,length)
double precision, intent(inout) :: x(width,length)
Like IFEM_Solve_shared, this routine solves the linear system
Like ``IFEM_Solve_shared``, this routine solves the linear system
:math:`A x = b` for the unknown vector :math:`x`. This routine,
however, adds support for boundary conditions associated with
:math:`x`. These so-called "essential" boundary conditions restrict
Expand All @@ -342,27 +344,28 @@ to 7.3 like this:
::

// C++ Example
int bcCount=2;
int bcDOF[bcCount];
double bcValue[bcCount];
// Fix node ny's y coordinate
bcDOF[0]=ny*width+1; // y is coordinate 1
bcValue[0]=4.6;
// Fix node nz's z coordinate
bcDOF[1]=nz*width+2; // z is coordinate 2
bcValue[1]=2.0;
int bcCount=2;
int bcDOF[bcCount];
double bcValue[bcCount];
// Fix node ny's y coordinate
bcDOF[0]=ny*width+1; // y is coordinate 1
bcValue[0]=4.6;
// Fix node nz's z coordinate
bcDOF[1]=nz*width+2; // z is coordinate 2
bcValue[1]=2.0;

.. code-block:: fortran
! F90 Example
// C++ Example
integer :: bcCount=2;
integer :: bcDOF(bcCount);
double precision :: bcValue(bcCount);
// Fix node ny's y coordinate
bcDOF(1)=(ny-1)*width+2; // y is coordinate 2
bcValue(1)=4.6;
// Fix node nz's z coordinate
bcDOF(2)=(nz-1)*width+3; // z is coordinate 3
bcValue(2)=2.0;
integer :: bcCount=2;
integer :: bcDOF(bcCount);
double precision :: bcValue(bcCount);
// Fix node ny's y coordinate
bcDOF(1)=(ny-1)*width+2; // y is coordinate 2
bcValue(1)=4.6;
// Fix node nz's z coordinate
bcDOF(2)=(nz-1)*width+3; // z is coordinate 3
bcValue(2)=2.0;
Mathematically, what is happening is we are splitting the partially
unknown vector :math:`x` into a completely unknown portion :math:`y` and
Expand All @@ -384,5 +387,3 @@ subroutine.
One important missing feature is the ability to specify general linear
constraints on the unknowns, rather than imposing specific values.

Index
=====

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