1 | /* |
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2 | * ----------------------------------------------------------------- |
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3 | * Programmer(s): Daniel Reynolds @ SMU |
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4 | * Based on code sundials_sptfqmr.h by: Aaron Collier @ LLNL |
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5 | * ----------------------------------------------------------------- |
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6 | * LLNS/SMU Copyright Start |
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7 | * Copyright (c) 2017, Southern Methodist University and |
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8 | * Lawrence Livermore National Security |
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9 | * |
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10 | * This work was performed under the auspices of the U.S. Department |
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11 | * of Energy by Southern Methodist University and Lawrence Livermore |
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12 | * National Laboratory under Contract DE-AC52-07NA27344. |
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13 | * Produced at Southern Methodist University and the Lawrence |
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14 | * Livermore National Laboratory. |
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15 | * |
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16 | * All rights reserved. |
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17 | * For details, see the LICENSE file. |
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18 | * LLNS/SMU Copyright End |
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19 | * ----------------------------------------------------------------- |
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20 | * This is the header file for the SPTFQMR implementation of the |
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21 | * SUNLINSOL module. The SPTFQMR algorithm is based on the |
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22 | * Scaled Preconditioned Transpose-free Quasi-Minimum Residual method. |
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23 | * |
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24 | * The SPTFQMR algorithm solves a linear system A x = b. |
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25 | * Preconditioning is allowed on the left, right, or both. |
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26 | * Scaling is allowed on both sides. |
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27 | * We denote the preconditioner and scaling matrices as follows: |
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28 | * P1 = left preconditioner |
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29 | * P2 = right preconditioner |
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30 | * S1 = diagonal matrix of scale factors for P1-inverse b |
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31 | * S2 = diagonal matrix of scale factors for P2 x |
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32 | * The matrices A, P1, and P2 are not required explicitly; only |
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33 | * routines that provide A, P1-inverse, and P2-inverse as |
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34 | * operators are required. |
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35 | * |
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36 | * In this notation, SPTFQMR applies the underlying TFQMR method to |
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37 | * the equivalent transformed system |
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38 | * Abar xbar = bbar , where |
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39 | * Abar = S1 (P1-inverse) A (P2-inverse) (S2-inverse) , |
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40 | * bbar = S1 (P1-inverse) b , and xbar = S2 P2 x . |
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41 | * |
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42 | * The scaling matrices must be chosen so that vectors S1 |
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43 | * P1-inverse b and S2 P2 x have dimensionless components. |
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44 | * If preconditioning is done on the left only (P2 = I), by a |
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45 | * matrix P, then S2 must be a scaling for x, while S1 is a |
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46 | * scaling for P-inverse b, and so may also be taken as a scaling |
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47 | * for x. Similarly, if preconditioning is done on the right only |
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48 | * (P1 = I, P2 = P), then S1 must be a scaling for b, while S2 is |
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49 | * a scaling for P x, and may also be taken as a scaling for b. |
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50 | * |
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51 | * The stopping test for the SPTFQMR iterations is on the L2 norm of |
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52 | * the scaled preconditioned residual: |
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53 | * || bbar - Abar xbar ||_2 < delta |
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54 | * with an input test constant delta. |
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55 | * |
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56 | * The usage of this SPTFQMR solver involves supplying up to three |
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57 | * routines and making a variety of calls. The user-supplied routines are |
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58 | * atimes (A_data, x, y) to compute y = A x, given x, |
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59 | * psolve (P_data, y, x, lr) to solve P1 x = y or P2 x = y for |
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60 | * x, given y, |
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61 | * psetup (P_data) to perform any 'setup' operations in |
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62 | * preparation for calling psolve. |
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63 | * The three user calls are: |
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64 | * SUNLinearSolver LS = SUNSPTFQMR(y, pretype, maxl); |
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65 | * to create the linear solver structure, |
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66 | * flag = SUNLinSolSetATimes(LS, A_data, atimes); |
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67 | * to set the matrix-vector product setup/apply routines, |
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68 | * flag = SUNLinSolSetPreconditioner(LS, P_data, psetup, psolve); |
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69 | * to *optionally* set the preconditioner setup/apply routines, |
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70 | * flag = SUNLinSolInitialize(LS); |
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71 | * to perform internal solver memory allocations, |
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72 | * flag = SUNLinSolSetup(LS, NULL); |
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73 | * to call the psetup routine (if non-NULL); |
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74 | * flag = SUNLinSolSolve(LS, NULL, x, b, w, tol); |
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75 | * to solve the linear system to the tolerance 'tol' |
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76 | * long int nli = SUNLinSolNumIters(LS); |
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77 | * to *optionally* retrieve the number of linear iterations |
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78 | * performed by the solver, |
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79 | * long int lastflag = SUNLinSolLastFlag(LS); |
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80 | * to *optionally* retrieve the last internal solver error flag, |
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81 | * flag = SUNLinSolFree(LS); |
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82 | * to free the solver memory. |
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83 | * Complete details for specifying atimes, psetup and psolve |
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84 | * and for the usage calls are given below. |
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85 | * |
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86 | * ----------------------------------------------------------------- |
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87 | * |
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88 | * Part I contains declarations specific to the SPTFQMR implementation |
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89 | * of the supplied SUNLINSOL module. |
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90 | * |
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91 | * Part II contains the prototype for the constructor |
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92 | * SUNSPTFQMR as well as implementation-specific prototypes |
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93 | * for various useful solver operations. |
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94 | * |
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95 | * Notes: |
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96 | * |
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97 | * - The definition of the generic SUNLinearSolver structure can |
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98 | * be found in the header file sundials_linearsolver.h. |
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99 | * |
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100 | * ----------------------------------------------------------------- |
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101 | */ |
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102 | |
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103 | #ifndef _SUNLINSOL_SPTFQMR_H |
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104 | #define _SUNLINSOL_SPTFQMR_H |
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105 | |
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106 | #include <sundials/sundials_linearsolver.h> |
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107 | #include <sundials/sundials_matrix.h> |
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108 | #include <sundials/sundials_nvector.h> |
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109 | #include <sundials/sundials_sptfqmr.h> |
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110 | |
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111 | #ifdef __cplusplus /* wrapper to enable C++ usage */ |
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112 | extern "C" { |
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113 | #endif |
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114 | |
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115 | /* Default SPTFQMR solver parameters */ |
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116 | #define SUNSPTFQMR_MAXL_DEFAULT 5 |
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117 | |
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118 | /* |
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119 | * ----------------------------------------------------------------- |
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120 | * PART I: SPTFQMR implementation of SUNLinearSolver |
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121 | * |
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122 | * The SPTFQMR implementation of the SUNLinearSolver 'content' |
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123 | * structure contains: |
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124 | * maxl -- number of BiCGStab iterations to allow |
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125 | * pretype -- flag for type of preconditioning to employ |
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126 | * numiters -- number of iterations from most-recent solve |
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127 | * resnorm -- final linear residual norm from most-recent solve |
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128 | * last_flag -- last error return flag from internal setup/solve |
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129 | * ATimes -- function pointer to ATimes routine |
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130 | * ATData -- pointer to structure for ATimes |
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131 | * Psetup -- function pointer to preconditioner setup routine |
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132 | * Psolve -- function pointer to preconditioner solve routine |
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133 | * PData -- pointer to structure for Psetup/Psolve |
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134 | * s1, s2 -- vector pointers for supplied scaling matrices |
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135 | * r_star -- a vector (type N_Vector) which holds the initial |
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136 | * scaled, preconditioned linear system residual |
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137 | * q, d, v, p and u -- vectors (type N_Vector) used for |
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138 | * workspace by the SPTFQMR algorithm |
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139 | * r -- array of vectors (type N_Vector) used for workspace |
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140 | * within the SPTFQMR algorithm |
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141 | * vtemp1/vtemp2/vtemp3 -- scratch vectors (type N_Vector) used |
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142 | * as temporary vector storage during calculations. |
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143 | * ----------------------------------------------------------------- |
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144 | */ |
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145 | |
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146 | struct _SUNLinearSolverContent_SPTFQMR { |
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147 | int maxl; |
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148 | int pretype; |
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149 | int numiters; |
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150 | realtype resnorm; |
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151 | long int last_flag; |
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152 | |
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153 | ATimesFn ATimes; |
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154 | void* ATData; |
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155 | PSetupFn Psetup; |
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156 | PSolveFn Psolve; |
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157 | void* PData; |
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158 | |
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159 | N_Vector s1; |
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160 | N_Vector s2; |
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161 | N_Vector r_star; |
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162 | N_Vector q; |
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163 | N_Vector d; |
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164 | N_Vector v; |
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165 | N_Vector p; |
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166 | N_Vector *r; |
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167 | N_Vector u; |
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168 | N_Vector vtemp1; |
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169 | N_Vector vtemp2; |
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170 | N_Vector vtemp3; |
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171 | }; |
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172 | |
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173 | typedef struct _SUNLinearSolverContent_SPTFQMR *SUNLinearSolverContent_SPTFQMR; |
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174 | |
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175 | /* |
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176 | * ----------------------------------------------------------------- |
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177 | * PART II: functions exported by sunlinsol_sptfqmr |
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178 | * |
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179 | * CONSTRUCTOR: |
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180 | * SUNSPTFQMR creates and allocates memory for a SPTFQMR solver |
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181 | * |
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182 | * "SET" ROUTINES: |
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183 | * SUNSPTFQMRSSetPrecType updates the type of preconditioning to |
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184 | * use. Supported values are PREC_NONE, PREC_LEFT, PREC_RIGHT |
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185 | * and PREC_BOTH. |
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186 | * SUNSPTFQMRSetMaxl updates the maximum number of iterations to |
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187 | * allow in the solver. |
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188 | * ----------------------------------------------------------------- |
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189 | */ |
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190 | |
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191 | SUNDIALS_EXPORT SUNLinearSolver SUNSPTFQMR(N_Vector y, int pretype, int maxl); |
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192 | SUNDIALS_EXPORT int SUNSPTFQMRSetPrecType(SUNLinearSolver S, int pretype); |
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193 | SUNDIALS_EXPORT int SUNSPTFQMRSetMaxl(SUNLinearSolver S, int maxl); |
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194 | |
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195 | /* |
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196 | * ----------------------------------------------------------------- |
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197 | * SPTFQMR implementations of various useful linear solver operations |
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198 | * ----------------------------------------------------------------- |
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199 | */ |
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200 | |
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201 | SUNDIALS_EXPORT SUNLinearSolver_Type SUNLinSolGetType_SPTFQMR(SUNLinearSolver S); |
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202 | SUNDIALS_EXPORT int SUNLinSolInitialize_SPTFQMR(SUNLinearSolver S); |
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203 | SUNDIALS_EXPORT int SUNLinSolSetATimes_SPTFQMR(SUNLinearSolver S, void* A_data, |
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204 | ATimesFn ATimes); |
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205 | SUNDIALS_EXPORT int SUNLinSolSetPreconditioner_SPTFQMR(SUNLinearSolver S, |
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206 | void* P_data, |
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207 | PSetupFn Pset, |
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208 | PSolveFn Psol); |
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209 | SUNDIALS_EXPORT int SUNLinSolSetScalingVectors_SPTFQMR(SUNLinearSolver S, |
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210 | N_Vector s1, |
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211 | N_Vector s2); |
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212 | SUNDIALS_EXPORT int SUNLinSolSetup_SPTFQMR(SUNLinearSolver S, SUNMatrix A); |
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213 | SUNDIALS_EXPORT int SUNLinSolSolve_SPTFQMR(SUNLinearSolver S, SUNMatrix A, |
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214 | N_Vector x, N_Vector b, realtype tol); |
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215 | SUNDIALS_EXPORT int SUNLinSolNumIters_SPTFQMR(SUNLinearSolver S); |
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216 | SUNDIALS_EXPORT realtype SUNLinSolResNorm_SPTFQMR(SUNLinearSolver S); |
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217 | SUNDIALS_EXPORT N_Vector SUNLinSolResid_SPTFQMR(SUNLinearSolver S); |
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218 | SUNDIALS_EXPORT long int SUNLinSolLastFlag_SPTFQMR(SUNLinearSolver S); |
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219 | SUNDIALS_EXPORT int SUNLinSolSpace_SPTFQMR(SUNLinearSolver S, |
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220 | long int *lenrwLS, |
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221 | long int *leniwLS); |
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222 | SUNDIALS_EXPORT int SUNLinSolFree_SPTFQMR(SUNLinearSolver S); |
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223 | |
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224 | |
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225 | #ifdef __cplusplus |
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226 | } |
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227 | #endif |
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228 | |
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229 | #endif |
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