src/libs/ck-libs/ifem/ilsic.h

   1 /**
   2 Iterative Linear Solvers: C-callable interface.
   3
   4 Orion Sky Lawlor, olawlor@acm.org, 1/16/2003
   5 */
   6 #ifndef __UIUC_CHARM_ILSI_C_H
   7 #define __UIUC_CHARM_ILSI_C_H
   8
   9 #ifdef __cplusplus
  10 extern "C" {
  11 #endif
  12
  13 /**
  14  * This struct gives the input and output parameters
  15  * for an IDXL_Solver. Because of fortran, it must be
  16  * layout-compatible with an array of 20 doubles,
  17  */
  18 typedef struct {
  19 /* Input parameters: */
  20   double maxResidual; /* (1) If nonzero, upper bound on total residual error. */
  21   double maxIterations; /* (2) If nonzero, upper bound on number of iterations to take. */
  22   double solverIn[8]; /* Solver-specific input parameters (normally 0) */
  23 /* Output parameters: */
  24   double residual; /* (11) Residual error of final solution (estimate) */
  25   double iterations; /* (12) Number of iterations actually taken. */
  26   double solverOut[8]; /* Solver-specific output parameters (normally 0) */
  27 } ILSI_Param;
  28
  29 /** Set default values for solver parameters. */
  30 void ILSI_Param_new(ILSI_Param *param);
  31
  32
  33 /** An ILSI_Comm is actually a C++ class--see ilsi.h */
  34 typedef struct ILSI_Comm ILSI_Comm;
  35
  36
  37 /**
  38  * An ILSI_Solver is a routine that computes, in parallel,
  39  * the solution x to the linear equation A x = b.
  40  * ILSI_Solvers must be written in C++, since ILSI_Comm is C++.
  41  *
  42  *   @param param Assorted input and output parameters for solver.
  43  *   @param comm The partitioned parallel matrix A and
  44  *                communication system for the solver.
  45  *   @param n The length of the local part of the solution vectors.
  46  *   @param b The local part of the known vector.  Never modified.
  47  *   @param x On input, the initial guess for the solution.
  48  *            During execution, the intermediate solution values.
  49  *            On output, the final solution.
  50  */
  51 typedef void (*ILSI_Solver)(ILSI_Param *param, ILSI_Comm *comm,
  52         int n, const double *b, double *x);
  53
  54 /** Conjugate-gradient solver: requires symmetric positive definite matrix */
  55 void ILSI_CG_Solver(ILSI_Param *param, ILSI_Comm *comm,
  56         int n, const double *b, double *x);
  57
  58
  59 #ifdef __cplusplus
  60 }
  61 #endif
  62
  63 #endif
  64