/*
 * -----------------------------------------------------------------
 * $Revision: 4923 $
 * $Date: 2016-09-19 14:35:51 -0700 (Mon, 19 Sep 2016) $
 * ----------------------------------------------------------------- 
 * Programmer(s): Aaron Collier and Radu Serban @ LLNL
 * -----------------------------------------------------------------
 * LLNS Copyright Start
 * Copyright (c) 2014, Lawrence Livermore National Security
 * This work was performed under the auspices of the U.S. Department 
 * of Energy by Lawrence Livermore National Laboratory in part under 
 * Contract W-7405-Eng-48 and in part under Contract DE-AC52-07NA27344.
 * Produced at the Lawrence Livermore National Laboratory.
 * All rights reserved.
 * For details, see the LICENSE file.
 * LLNS Copyright End
 * -----------------------------------------------------------------
 * This is the implementation file for the CVSPTFQMR linear solver.
 * -----------------------------------------------------------------
 */

#include <stdio.h>
#include <stdlib.h>

#include <cvodes/cvodes_sptfqmr.h>
#include "cvodes_spils_impl.h"
#include "cvodes_impl.h"

#include <sundials/sundials_sptfqmr.h>
#include <sundials/sundials_math.h>

/* Constants */

#define ZERO RCONST(0.0)
#define ONE  RCONST(1.0)

/* CVSPTFQMR linit, lsetup, lsolve, and lfree routines */

static int CVSptfqmrInit(CVodeMem cv_mem);

static int CVSptfqmrSetup(CVodeMem cv_mem, int convfail, N_Vector ypred,
                          N_Vector fpred, booleantype *jcurPtr, N_Vector vtemp1,
                          N_Vector vtemp2, N_Vector vtemp3);

static int CVSptfqmrSolve(CVodeMem cv_mem, N_Vector b, N_Vector weight,
                          N_Vector ynow, N_Vector fnow);

static int CVSptfqmrFree(CVodeMem cv_mem);

/* CVSPTFQMR lfreeB function */

static int CVSptfqmrFreeB(CVodeBMem cvB_mem);

/* 
 * ================================================================
 *
 *                   PART I - forward problems
 *
 * ================================================================
 */

/* Readability Replacements */

#define tq           (cv_mem->cv_tq)
#define nst          (cv_mem->cv_nst)
#define tn           (cv_mem->cv_tn)
#define gamma        (cv_mem->cv_gamma)
#define gammap       (cv_mem->cv_gammap)
#define f            (cv_mem->cv_f)
#define user_data    (cv_mem->cv_user_data)
#define ewt          (cv_mem->cv_ewt)
#define errfp        (cv_mem->cv_errfp)
#define mnewt        (cv_mem->cv_mnewt)
#define linit        (cv_mem->cv_linit)
#define lsetup       (cv_mem->cv_lsetup)
#define lsolve       (cv_mem->cv_lsolve)
#define lfree        (cv_mem->cv_lfree)
#define lmem         (cv_mem->cv_lmem)
#define vec_tmpl     (cv_mem->cv_tempv)
#define setupNonNull (cv_mem->cv_setupNonNull)

#define sqrtN       (cvspils_mem->s_sqrtN)   
#define ytemp       (cvspils_mem->s_ytemp)
#define x           (cvspils_mem->s_x)
#define ycur        (cvspils_mem->s_ycur)
#define fcur        (cvspils_mem->s_fcur)
#define delta       (cvspils_mem->s_delta)
#define deltar      (cvspils_mem->s_deltar)
#define npe         (cvspils_mem->s_npe)
#define nli         (cvspils_mem->s_nli)
#define nps         (cvspils_mem->s_nps)
#define ncfl        (cvspils_mem->s_ncfl)
#define nstlpre     (cvspils_mem->s_nstlpre)
#define njtimes     (cvspils_mem->s_njtimes)
#define nfes        (cvspils_mem->s_nfes)
#define spils_mem   (cvspils_mem->s_spils_mem)

#define jtimesDQ    (cvspils_mem->s_jtimesDQ)
#define jtimes      (cvspils_mem->s_jtimes)
#define j_data      (cvspils_mem->s_j_data)

#define last_flag   (cvspils_mem->s_last_flag)

/*
 * -----------------------------------------------------------------
 * Function : CVSptfqmr
 * -----------------------------------------------------------------
 * This routine initializes the memory record and sets various function
 * fields specific to the Sptfqmr linear solver module. CVSptfqmr first
 * calls the existing lfree routine if this is not NULL. It then sets
 * the cv_linit, cv_lsetup, cv_lsolve, cv_lfree fields in (*cvode_mem)
 * to be CVSptfqmrInit, CVSptfqmrSetup, CVSptfqmrSolve, and CVSptfqmrFree,
 * respectively. It allocates memory for a structure of type
 * CVSpilsMemRec and sets the cv_lmem field in (*cvode_mem) to the
 * address of this structure. It sets setupNonNull in (*cvode_mem),
 * and sets various fields in the CVSpilsMemRec structure.
 * Finally, CVSptfqmr allocates memory for ytemp and x, and calls
 * SptfqmrMalloc to allocate memory for the Sptfqmr solver.
 * -----------------------------------------------------------------
 */

int CVSptfqmr(void *cvode_mem, int pretype, int maxl)
{
  CVodeMem cv_mem;
  CVSpilsMem cvspils_mem;
  SptfqmrMem sptfqmr_mem;
  int mxl;

  /* Return immediately if cvode_mem is NULL */
  if (cvode_mem == NULL) {
    cvProcessError(NULL, CVSPILS_MEM_NULL, "CVSPTFQMR", "CVSptfqmr", MSGS_CVMEM_NULL);
    return(CVSPILS_MEM_NULL);
  }
  cv_mem = (CVodeMem) cvode_mem;

  /* Check if N_VDotProd is present */
  if (vec_tmpl->ops->nvdotprod == NULL) {
    cvProcessError(cv_mem, CVSPILS_ILL_INPUT, "CVSPTFQMR", "CVSptfqmr", MSGS_BAD_NVECTOR);
    return(CVSPILS_ILL_INPUT);
  }

  if (lfree != NULL) lfree(cv_mem);

  /* Set four main function fields in cv_mem */
  linit  = CVSptfqmrInit;
  lsetup = CVSptfqmrSetup;
  lsolve = CVSptfqmrSolve;
  lfree  = CVSptfqmrFree;

  /* Get memory for CVSpilsMemRec */
  cvspils_mem = NULL;
  cvspils_mem = (CVSpilsMem) malloc(sizeof(struct CVSpilsMemRec));
  if (cvspils_mem == NULL) {
    cvProcessError(cv_mem, CVSPILS_MEM_FAIL, "CVSPTFQMR", "CVSptfqmr", MSGS_MEM_FAIL);
    return(CVSPILS_MEM_FAIL);
  }

  /* Set ILS type */
  cvspils_mem->s_type = SPILS_SPTFQMR;

  /* Set Sptfqmr parameters that have been passed in call sequence */
  cvspils_mem->s_pretype = pretype;
  mxl = cvspils_mem->s_maxl = (maxl <= 0) ? CVSPILS_MAXL : maxl;

  /* Set defaults for Jacobian-related fileds */
  jtimesDQ = TRUE;
  jtimes   = NULL;
  j_data   = NULL;

  /* Set defaults for preconditioner-related fields */
  cvspils_mem->s_pset   = NULL;
  cvspils_mem->s_psolve = NULL;
  cvspils_mem->s_pfree  = NULL;
  cvspils_mem->s_P_data = cv_mem->cv_user_data;

  /* Set default values for the rest of the Sptfqmr parameters */
  cvspils_mem->s_eplifac   = CVSPILS_EPLIN;

  cvspils_mem->s_last_flag = CVSPILS_SUCCESS;

  cvSpilsInitializeCounters(cvspils_mem);

  setupNonNull = FALSE;

  /* Check for legal pretype */ 
  if ((pretype != PREC_NONE) && (pretype != PREC_LEFT) &&
      (pretype != PREC_RIGHT) && (pretype != PREC_BOTH)) {
    cvProcessError(cv_mem, CVSPILS_ILL_INPUT, "CVSPTFQMR", "CVSptfqmr", MSGS_BAD_PRETYPE);
    free(cvspils_mem); cvspils_mem = NULL;
    return(CVSPILS_ILL_INPUT);
  }

  /* Allocate memory for ytemp and x */
  ytemp = N_VClone(vec_tmpl);
  if (ytemp == NULL) {
    cvProcessError(cv_mem, CVSPILS_MEM_FAIL, "CVSPTFQMR", "CVSptfqmr", MSGS_MEM_FAIL);
    free(cvspils_mem); cvspils_mem = NULL;
    return(CVSPILS_MEM_FAIL);
  }
  x = N_VClone(vec_tmpl);
  if (x == NULL) {
    cvProcessError(cv_mem, CVSPILS_MEM_FAIL, "CVSPTFQMR", "CVSptfqmr", MSGS_MEM_FAIL);
    N_VDestroy(ytemp);
    free(cvspils_mem); cvspils_mem = NULL;
    return(CVSPILS_MEM_FAIL);
  }

  /* Compute sqrtN from a dot product */
  N_VConst(ONE, ytemp);
  sqrtN = SUNRsqrt(N_VDotProd(ytemp, ytemp));

  /* Call SptfqmrMalloc to allocate workspace for Sptfqmr */
  sptfqmr_mem = NULL;
  sptfqmr_mem = SptfqmrMalloc(mxl, vec_tmpl);
  if (sptfqmr_mem == NULL) {
    cvProcessError(cv_mem, CVSPILS_MEM_FAIL, "CVSPTFQMR", "CVSptfqmr", MSGS_MEM_FAIL);
    N_VDestroy(ytemp);
    N_VDestroy(x);
    free(cvspils_mem); cvspils_mem = NULL;
    return(CVSPILS_MEM_FAIL);
  }
  
  /* Attach SPTFQMR memory to spils memory structure */
  spils_mem = (void *) sptfqmr_mem;

  /* Attach linear solver memory to integrator memory */
  lmem = cvspils_mem;

  return(CVSPILS_SUCCESS);
}

/* Additional readability replacements */

#define pretype (cvspils_mem->s_pretype)
#define eplifac (cvspils_mem->s_eplifac)
#define maxl    (cvspils_mem->s_maxl)
#define psolve  (cvspils_mem->s_psolve)
#define pset    (cvspils_mem->s_pset)
#define P_data  (cvspils_mem->s_P_data)

/*
 * -----------------------------------------------------------------
 * Function : CVSptfqmrInit
 * -----------------------------------------------------------------
 * This routine does remaining initializations specific to the Sptfqmr
 * linear solver.
 * -----------------------------------------------------------------
 */

static int CVSptfqmrInit(CVodeMem cv_mem)
{
  CVSpilsMem cvspils_mem;
  SptfqmrMem sptfqmr_mem;

  cvspils_mem = (CVSpilsMem) lmem;
  sptfqmr_mem = (SptfqmrMem) spils_mem;

  /* Initialize counters */
  cvSpilsInitializeCounters(cvspils_mem);

  /* Check for legal combination pretype - psolve */
  if ((pretype != PREC_NONE) && (psolve == NULL)) {
    cvProcessError(cv_mem, -1, "CVSPTFQMR", "CVSptfqmrInit", MSGS_PSOLVE_REQ);
    last_flag = CVSPILS_ILL_INPUT;
    return(-1);
  }

  /* Set setupNonNull = TRUE iff there is preconditioning
     (pretype != PREC_NONE)  and there is a preconditioning
     setup phase (pset != NULL) */
  setupNonNull = (pretype != PREC_NONE) && (pset != NULL);

  /* Set Jacobian-related fields, based on jtimesDQ */
  if (jtimesDQ) {
    jtimes = CVSpilsDQJtimes;
    j_data = cv_mem;
  } else {
    j_data = user_data;
  }

  /*  Set maxl in the SPTFQMR memory in case it was changed by the user */
  sptfqmr_mem->l_max  = maxl;

  last_flag = CVSPILS_SUCCESS;
  return(0);
}

/*
 * -----------------------------------------------------------------
 * Function : CVSptfqmrSetup
 * -----------------------------------------------------------------
 * This routine does the setup operations for the Sptfqmr linear solver.
 * It makes a decision as to whether or not to signal for reevaluation
 * of Jacobian data in the pset routine, based on various state
 * variables, then it calls pset. If we signal for reevaluation,
 * then we reset jcur = *jcurPtr to TRUE, regardless of the pset output.
 * In any case, if jcur == TRUE, we increment npe and save nst in nstlpre.
 * -----------------------------------------------------------------
 */

static int CVSptfqmrSetup(CVodeMem cv_mem, int convfail, N_Vector ypred,
			  N_Vector fpred, booleantype *jcurPtr, N_Vector vtemp1,
			  N_Vector vtemp2, N_Vector vtemp3)
{
  booleantype jbad, jok;
  realtype dgamma;
  int  retval;
  CVSpilsMem cvspils_mem;

  cvspils_mem = (CVSpilsMem) lmem;

  /* Use nst, gamma/gammap, and convfail to set J eval. flag jok */
  dgamma = SUNRabs((gamma/gammap) - ONE);
  jbad = (nst == 0) || (nst > nstlpre + CVSPILS_MSBPRE) ||
      ((convfail == CV_FAIL_BAD_J) && (dgamma < CVSPILS_DGMAX)) ||
      (convfail == CV_FAIL_OTHER);
  *jcurPtr = jbad;
  jok = !jbad;

  /* Call pset routine and possibly reset jcur */
  retval = pset(tn, ypred, fpred, jok, jcurPtr, gamma, P_data, 
                vtemp1, vtemp2, vtemp3);
  if (retval < 0) {
    cvProcessError(cv_mem, SPTFQMR_PSET_FAIL_UNREC, "CVSPTFQMR", "CVSptfqmrSetup", MSGS_PSET_FAILED);
    last_flag = SPTFQMR_PSET_FAIL_UNREC;
  }
  if (retval > 0) {
    last_flag = SPTFQMR_PSET_FAIL_REC;
  }

  if (jbad) *jcurPtr = TRUE;

  /* If jcur = TRUE, increment npe and save nst value */
  if (*jcurPtr) {
    npe++;
    nstlpre = nst;
  }

  last_flag = SPTFQMR_SUCCESS;

  /* Return the same value that pset returned */
  return(retval);
}

/*
 * -----------------------------------------------------------------
 * Function : CVSptfqmrSolve
 * -----------------------------------------------------------------
 * This routine handles the call to the generic solver SptfqmrSolve
 * for the solution of the linear system Ax = b with the SPTFQMR method.
 * The solution x is returned in the vector b.
 *
 * If the WRMS norm of b is small, we return x = b (if this is the first
 * Newton iteration) or x = 0 (if a later Newton iteration).
 *
 * Otherwise, we set the tolerance parameter and initial guess (x = 0),
 * call SptfqmrSolve, and copy the solution x into b. The x-scaling and
 * b-scaling arrays are both equal to weight.
 *
 * The counters nli, nps, and ncfl are incremented, and the return value
 * is set according to the success of SptfqmrSolve. The success flag is
 * returned if SptfqmrSolve converged, or if this is the first Newton
 * iteration and the residual norm was reduced below its initial value.
 * -----------------------------------------------------------------
 */

static int CVSptfqmrSolve(CVodeMem cv_mem, N_Vector b, N_Vector weight,
			  N_Vector ynow, N_Vector fnow)
{
  realtype bnorm, res_norm;
  CVSpilsMem cvspils_mem;
  SptfqmrMem sptfqmr_mem;
  int nli_inc, nps_inc, retval;
  
  cvspils_mem = (CVSpilsMem) lmem;

  sptfqmr_mem = (SptfqmrMem) spils_mem;

  /* Test norm(b); if small, return x = 0 or x = b */
  deltar = eplifac * tq[4]; 

  bnorm = N_VWrmsNorm(b, weight);
  if (bnorm <= deltar) {
    if (mnewt > 0) N_VConst(ZERO, b); 
    return(0);
  }

  /* Set vectors ycur and fcur for use by the Atimes and Psolve routines */
  ycur = ynow;
  fcur = fnow;

  /* Set inputs delta and initial guess x = 0 to SptfqmrSolve */  
  delta = deltar * sqrtN;
  N_VConst(ZERO, x);
  
  /* Call SptfqmrSolve and copy x to b */
  retval = SptfqmrSolve(sptfqmr_mem, cv_mem, x, b, pretype, delta,
                        cv_mem, weight, weight, CVSpilsAtimes, CVSpilsPSolve,
                        &res_norm, &nli_inc, &nps_inc);

  N_VScale(ONE, x, b);
  
  /* Increment counters nli, nps, and ncfl */
  nli += nli_inc;
  nps += nps_inc;
  if (retval != SPTFQMR_SUCCESS) ncfl++;

  /* Interpret return value from SpgmrSolve */

  last_flag = retval;

  switch(retval) {

  case SPTFQMR_SUCCESS:
    return(0);
    break;
  case SPTFQMR_RES_REDUCED:
    if (mnewt == 0) return(0);
    else            return(1);
    break;
  case SPTFQMR_CONV_FAIL:
    return(1);
    break;
  case SPTFQMR_PSOLVE_FAIL_REC:
    return(1);
    break;
  case SPTFQMR_ATIMES_FAIL_REC:
    return(1);
    break;
  case SPTFQMR_MEM_NULL:
    return(-1);
    break;
  case SPTFQMR_ATIMES_FAIL_UNREC:
    cvProcessError(cv_mem, SPTFQMR_ATIMES_FAIL_UNREC, "CVSPTFQMR", "CVSptfqmrSolve", MSGS_JTIMES_FAILED);    
    return(-1);
    break;
  case SPTFQMR_PSOLVE_FAIL_UNREC:
    cvProcessError(cv_mem, SPTFQMR_PSOLVE_FAIL_UNREC, "CVSPTFQMR", "CVSptfqmrSolve", MSGS_PSOLVE_FAILED);
    return(-1);
    break;
  }

  return(0);  

}

/*
 * -----------------------------------------------------------------
 * Function : CVSptfqmrFree
 * -----------------------------------------------------------------
 * This routine frees memory specific to the Sptfqmr linear solver.
 * -----------------------------------------------------------------
 */

static int CVSptfqmrFree(CVodeMem cv_mem)
{
  CVSpilsMem cvspils_mem;
  SptfqmrMem sptfqmr_mem;
    
  cvspils_mem = (CVSpilsMem) lmem;

  N_VDestroy(ytemp);
  N_VDestroy(x);

  sptfqmr_mem = (SptfqmrMem) spils_mem;
  SptfqmrFree(sptfqmr_mem);

  if (cvspils_mem->s_pfree != NULL) (cvspils_mem->s_pfree)(cv_mem);

  free(cvspils_mem);
  cv_mem->cv_lmem = NULL;

  return(0);
}

/* 
 * ================================================================
 *
 *                   PART II - backward problems
 *
 * ================================================================
 */
      
/* Additional readability replacements */

#define pset_B      (cvspilsB_mem->s_psetB)
#define psolve_B    (cvspilsB_mem->s_psolveB)
#define jtimes_B    (cvspilsB_mem->s_jtimesB)
#define P_data_B    (cvspilsB_mem->s_P_dataB)

/*
 * CVSptfqmrB
 *
 * Wrapper for the backward phase
 */

int CVSptfqmrB(void *cvode_mem, int which, int pretypeB, int maxlB)
{
  CVodeMem cv_mem;
  CVadjMem ca_mem;
  CVodeBMem cvB_mem;
  void *cvodeB_mem;
  CVSpilsMemB cvspilsB_mem;
  int flag;

  /* Check if cvode_mem exists */
  if (cvode_mem == NULL) {
    cvProcessError(NULL, CVSPILS_MEM_NULL, "CVSPTFQMR", "CVSptfqmrB", MSGS_CVMEM_NULL);
    return(CVSPILS_MEM_NULL);
  }
  cv_mem = (CVodeMem) cvode_mem;

  /* Was ASA initialized? */
  if (cv_mem->cv_adjMallocDone == FALSE) {
    cvProcessError(cv_mem, CVSPILS_NO_ADJ, "CVSPTFQMR", "CVSptfqmrB", MSGS_NO_ADJ);
    return(CVSPILS_NO_ADJ);
  } 
  ca_mem = cv_mem->cv_adj_mem;

  /* Check which */
  if ( which >= ca_mem->ca_nbckpbs ) {
    cvProcessError(cv_mem, CVSPILS_ILL_INPUT, "CVSPTFQMR", "CVSptfqmrB", MSGS_BAD_WHICH);
    return(CVSPILS_ILL_INPUT);
  }

  /* Find the CVodeBMem entry in the linked list corresponding to which */
  cvB_mem = ca_mem->cvB_mem;
  while (cvB_mem != NULL) {
    if ( which == cvB_mem->cv_index ) break;
    cvB_mem = cvB_mem->cv_next;
  }

  cvodeB_mem = (void *) (cvB_mem->cv_mem);

  /* Get memory for CVSpilsMemRecB */
  cvspilsB_mem = NULL;
  cvspilsB_mem = (CVSpilsMemB) malloc(sizeof(struct CVSpilsMemRecB));
  if (cvspilsB_mem == NULL) {
    cvProcessError(cv_mem, CVSPILS_MEM_FAIL, "CVSPTFQMR", "CVSptfqmrB", MSGS_MEM_FAIL);
    return(CVSPILS_MEM_FAIL);
  }

  pset_B = NULL;
  psolve_B = NULL;
  P_data_B = NULL;

  /* initialize Jacobian function */
  jtimes_B = NULL;

  /* attach lmemB and lfreeB */
  cvB_mem->cv_lmem = cvspilsB_mem;
  cvB_mem->cv_lfree = CVSptfqmrFreeB;

  flag = CVSptfqmr(cvodeB_mem, pretypeB, maxlB);

  if (flag != CVSPILS_SUCCESS) {
    free(cvspilsB_mem); 
    cvspilsB_mem = NULL;
  }

  return(flag);
}

/*
 * CVSptfqmrFreeB 
 */


static int CVSptfqmrFreeB(CVodeBMem cvB_mem)
{
  CVSpilsMemB cvspilsB_mem;

  cvspilsB_mem = (CVSpilsMemB) (cvB_mem->cv_lmem);

  free(cvspilsB_mem);

  return(0);
}
