1 | /* |
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2 | * ----------------------------------------------------------------- |
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3 | * $Revision$ |
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4 | * $Date$ |
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5 | * ----------------------------------------------------------------- |
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6 | * Programmer(s): Peter Brown and Aaron Collier @ LLNL |
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7 | * ----------------------------------------------------------------- |
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8 | * LLNS Copyright Start |
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9 | * Copyright (c) 2014, Lawrence Livermore National Security |
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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 Lawrence Livermore National Laboratory in part under |
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12 | * Contract W-7405-Eng-48 and in part under Contract DE-AC52-07NA27344. |
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13 | * Produced at the Lawrence Livermore National Laboratory. |
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14 | * All rights reserved. |
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15 | * For details, see the LICENSE file. |
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16 | * LLNS Copyright End |
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17 | * ----------------------------------------------------------------- |
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18 | * This is the header file for the implementation of the scaled, |
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19 | * preconditioned Bi-CGSTAB (SPBCG) iterative linear solver. |
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20 | * ----------------------------------------------------------------- |
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21 | */ |
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22 | |
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23 | #ifndef _SPBCG_H |
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24 | #define _SPBCG_H |
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25 | |
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26 | #include <sundials/sundials_iterative.h> |
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27 | |
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28 | #ifdef __cplusplus /* wrapper to enable C++ usage */ |
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29 | extern "C" { |
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30 | #endif |
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31 | |
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32 | /* |
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33 | * ----------------------------------------------------------------- |
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34 | * Types: struct SpbcgMemRec and struct *SpbcgMem |
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35 | * ----------------------------------------------------------------- |
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36 | * A variable declaration of type struct *SpbcgMem denotes a pointer |
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37 | * to a data structure of type struct SpbcgMemRec. The SpbcgMemRec |
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38 | * structure contains numerous fields that must be accessed by the |
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39 | * SPBCG linear solver module. |
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40 | * |
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41 | * l_max maximum Krylov subspace dimension that SpbcgSolve will |
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42 | * be permitted to use |
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43 | * |
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44 | * r vector (type N_Vector) which holds the scaled, preconditioned |
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45 | * linear system residual |
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46 | * |
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47 | * r_star vector (type N_Vector) which holds the initial scaled, |
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48 | * preconditioned linear system residual |
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49 | * |
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50 | * p, q, u and Ap vectors (type N_Vector) used for workspace by |
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51 | * the SPBCG algorithm |
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52 | * |
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53 | * vtemp scratch vector (type N_Vector) used as temporary vector |
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54 | * storage |
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55 | * ----------------------------------------------------------------- |
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56 | */ |
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57 | |
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58 | typedef struct { |
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59 | |
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60 | int l_max; |
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61 | |
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62 | N_Vector r_star; |
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63 | N_Vector r; |
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64 | N_Vector p; |
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65 | N_Vector q; |
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66 | N_Vector u; |
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67 | N_Vector Ap; |
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68 | N_Vector vtemp; |
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69 | |
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70 | } SpbcgMemRec, *SpbcgMem; |
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71 | |
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72 | /* |
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73 | * ----------------------------------------------------------------- |
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74 | * Function : SpbcgMalloc |
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75 | * ----------------------------------------------------------------- |
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76 | * SpbcgMalloc allocates additional memory needed by the SPBCG |
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77 | * linear solver module. |
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78 | * |
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79 | * l_max maximum Krylov subspace dimension that SpbcgSolve will |
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80 | * be permitted to use |
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81 | * |
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82 | * vec_tmpl implementation-specific template vector (type N_Vector) |
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83 | * (created using either N_VNew_Serial or N_VNew_Parallel) |
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84 | * |
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85 | * If successful, SpbcgMalloc returns a non-NULL memory pointer. If |
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86 | * an error occurs, then a NULL pointer is returned. |
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87 | * ----------------------------------------------------------------- |
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88 | */ |
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89 | |
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90 | SUNDIALS_EXPORT SpbcgMem SpbcgMalloc(int l_max, N_Vector vec_tmpl); |
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91 | |
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92 | /* |
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93 | * ----------------------------------------------------------------- |
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94 | * Function : SpbcgSolve |
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95 | * ----------------------------------------------------------------- |
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96 | * SpbcgSolve solves the linear system Ax = b by means of a scaled |
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97 | * preconditioned Bi-CGSTAB (SPBCG) iterative method. |
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98 | * |
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99 | * mem pointer to an internal memory block allocated during a |
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100 | * prior call to SpbcgMalloc |
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101 | * |
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102 | * A_data pointer to a data structure containing information |
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103 | * about the coefficient matrix A (passed to user-supplied |
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104 | * function referenced by atimes (function pointer)) |
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105 | * |
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106 | * x vector (type N_Vector) containing initial guess x_0 upon |
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107 | * entry, but which upon return contains an approximate solution |
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108 | * of the linear system Ax = b (solution only valid if return |
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109 | * value is either SPBCG_SUCCESS or SPBCG_RES_REDUCED) |
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110 | * |
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111 | * b vector (type N_Vector) set to the right-hand side vector b |
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112 | * of the linear system (undisturbed by function) |
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113 | * |
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114 | * pretype variable (type int) indicating the type of |
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115 | * preconditioning to be used (see sundials_iterative.h) |
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116 | * |
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117 | * delta tolerance on the L2 norm of the scaled, preconditioned |
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118 | * residual (if return value == SPBCG_SUCCESS, then |
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119 | * ||sb*P1_inv*(b-Ax)||_L2 <= delta) |
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120 | * |
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121 | * P_data pointer to a data structure containing preconditioner |
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122 | * information (passed to user-supplied function referenced |
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123 | * by psolve (function pointer)) |
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124 | * |
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125 | * sx vector (type N_Vector) containing positive scaling factors |
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126 | * for x (pass sx == NULL if scaling NOT required) |
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127 | * |
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128 | * sb vector (type N_Vector) containing positive scaling factors |
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129 | * for b (pass sb == NULL if scaling NOT required) |
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130 | * |
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131 | * atimes user-supplied routine responsible for computing the |
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132 | * matrix-vector product Ax (see sundials_iterative.h) |
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133 | * |
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134 | * psolve user-supplied routine responsible for solving the |
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135 | * preconditioned linear system Pz = r (ignored if |
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136 | * pretype == PREC_NONE) (see sundials_iterative.h) |
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137 | * |
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138 | * res_norm pointer (type realtype*) to the L2 norm of the |
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139 | * scaled, preconditioned residual (if return value |
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140 | * is either SPBCG_SUCCESS or SPBCG_RES_REDUCED, then |
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141 | * *res_norm = ||sb*P1_inv*(b-Ax)||_L2, where x is |
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142 | * the computed approximate solution, sb is the diagonal |
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143 | * scaling matrix for the right-hand side b, and P1_inv |
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144 | * is the inverse of the left-preconditioner matrix) |
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145 | * |
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146 | * nli pointer (type int*) to the total number of linear |
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147 | * iterations performed |
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148 | * |
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149 | * nps pointer (type int*) to the total number of calls made |
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150 | * to the psolve routine |
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151 | * ----------------------------------------------------------------- |
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152 | */ |
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153 | |
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154 | SUNDIALS_EXPORT int SpbcgSolve(SpbcgMem mem, void *A_data, N_Vector x, N_Vector b, |
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155 | int pretype, realtype delta, void *P_data, N_Vector sx, |
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156 | N_Vector sb, ATimesFn atimes, PSolveFn psolve, |
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157 | realtype *res_norm, int *nli, int *nps); |
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158 | |
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159 | /* Return values for SpbcgSolve */ |
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160 | |
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161 | #define SPBCG_SUCCESS 0 /* SPBCG algorithm converged */ |
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162 | #define SPBCG_RES_REDUCED 1 /* SPBCG did NOT converge, but the |
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163 | residual was reduced */ |
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164 | #define SPBCG_CONV_FAIL 2 /* SPBCG algorithm failed to converge */ |
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165 | #define SPBCG_PSOLVE_FAIL_REC 3 /* psolve failed recoverably */ |
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166 | #define SPBCG_ATIMES_FAIL_REC 4 /* atimes failed recoverably */ |
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167 | #define SPBCG_PSET_FAIL_REC 5 /* pset faild recoverably */ |
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168 | |
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169 | #define SPBCG_MEM_NULL -1 /* mem argument is NULL */ |
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170 | #define SPBCG_ATIMES_FAIL_UNREC -2 /* atimes returned failure flag */ |
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171 | #define SPBCG_PSOLVE_FAIL_UNREC -3 /* psolve failed unrecoverably */ |
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172 | #define SPBCG_PSET_FAIL_UNREC -4 /* pset failed unrecoverably */ |
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173 | |
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174 | /* |
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175 | * ----------------------------------------------------------------- |
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176 | * Function : SpbcgFree |
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177 | * ----------------------------------------------------------------- |
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178 | * SpbcgFree frees the memory allocated by a call to SpbcgMalloc. |
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179 | * It is illegal to use the pointer mem after a call to SpbcgFree. |
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180 | * ----------------------------------------------------------------- |
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181 | */ |
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182 | |
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183 | SUNDIALS_EXPORT void SpbcgFree(SpbcgMem mem); |
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184 | |
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185 | /* |
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186 | * ----------------------------------------------------------------- |
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187 | * Macro : SPBCG_VTEMP |
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188 | * ----------------------------------------------------------------- |
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189 | * This macro provides access to the vector r in the |
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190 | * memory block of the SPBCG module. The argument mem is the |
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191 | * memory pointer returned by SpbcgMalloc, of type SpbcgMem, |
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192 | * and the macro value is of type N_Vector. |
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193 | * |
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194 | * Note: Only used by IDA (r contains P_inverse F if nli_inc == 0). |
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195 | * ----------------------------------------------------------------- |
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196 | */ |
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197 | |
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198 | #define SPBCG_VTEMP(mem) (mem->r) |
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199 | |
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200 | #ifdef __cplusplus |
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201 | } |
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202 | #endif |
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203 | |
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204 | #endif |
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