| | 1 | = Ex21.c = |
| | 2 | {{{#!C |
| | 3 | /* |
| | 4 | Large Scale Computing |
| | 5 | 1D Heat/Mass Transfer |
| | 6 | ex21.c : use cg.c |
| | 7 | */ |
| | 8 | #include<stdio.h> |
| | 9 | #include<stdlib.h> |
| | 10 | #include<math.h> |
| | 11 | #include"cg.h" |
| | 12 | |
| | 13 | int main(int argc, char **argv){ |
| | 14 | double a,b,d; |
| | 15 | double *phi; |
| | 16 | double *rhs; |
| | 17 | double dx; |
| | 18 | double tol = 1.0e-12; |
| | 19 | int i,num,itc; |
| | 20 | double *nzval; /* non-zero elements of A */ |
| | 21 | int *colind; /* column indices of nonzeros */ |
| | 22 | int *rowptr; /* row info */ |
| | 23 | int nnz; |
| | 24 | FILE *fp; |
| | 25 | |
| | 26 | if (argc < 5){ |
| | 27 | printf("Usage:%s [NUM] [A] [B] [D]\n",argv[0]); |
| | 28 | exit(-1); |
| | 29 | } |
| | 30 | |
| | 31 | /* set parameters */ |
| | 32 | num = atoi(argv[1]); |
| | 33 | a = atof(argv[2]); |
| | 34 | b = atof(argv[3]); |
| | 35 | d = atof(argv[4]); |
| | 36 | |
| | 37 | printf("num=%d A=%e B=%e D=%e\n",num,a,b,d); |
| | 38 | |
| | 39 | /* Memory Allocation and Check*/ |
| | 40 | phi = (double *)calloc(num, sizeof(double)); |
| | 41 | rhs = (double *)calloc(num, sizeof(double)); |
| | 42 | nzval = (double *)calloc(3 * num, sizeof(double)); |
| | 43 | colind = (int *)calloc(3 * num, sizeof(int)); |
| | 44 | rowptr = (int *)calloc(num + 1, sizeof(int)); |
| | 45 | if ((phi == NULL) || (rhs == NULL) || |
| | 46 | (nzval == NULL) || (colind == NULL) || (rowptr == NULL)){ |
| | 47 | printf("Memory Allocation Failed\n"); |
| | 48 | exit(-1); |
| | 49 | } |
| | 50 | |
| | 51 | /** Setup **/ |
| | 52 | dx = 1.0 / (double)(num - 1); |
| | 53 | |
| | 54 | /* Boundary Condition*/ |
| | 55 | phi[0] = a; |
| | 56 | phi[num-1] = b; |
| | 57 | |
| | 58 | /* Setup Matrix A and RHS */ |
| | 59 | nnz = 0; |
| | 60 | for (i = 1 ; i < num - 1 ; i++){ |
| | 61 | |
| | 62 | /* set general RHS */ |
| | 63 | rhs[i] = -dx * dx / d * (dx * (double)i); |
| | 64 | |
| | 65 | /* set first nonzero column of row index(i,j) */ |
| | 66 | rowptr[i - 1] = nnz; |
| | 67 | |
| | 68 | /* west */ |
| | 69 | if (i == 1){ |
| | 70 | rhs[i] -= phi[0]; |
| | 71 | }else{ |
| | 72 | nzval[nnz] = 1.0; |
| | 73 | colind[nnz] = i-2; |
| | 74 | nnz++; |
| | 75 | } |
| | 76 | |
| | 77 | /* diagonal Element */ |
| | 78 | nzval[nnz] = -2.0; |
| | 79 | colind[nnz] = i - 1; |
| | 80 | nnz++; |
| | 81 | |
| | 82 | /* east */ |
| | 83 | if (i == num - 2){ |
| | 84 | rhs[i] -= phi[num-1]; |
| | 85 | }else{ |
| | 86 | nzval[nnz] = 1.0; |
| | 87 | colind[nnz] = i; |
| | 88 | nnz++; |
| | 89 | } |
| | 90 | } |
| | 91 | |
| | 92 | /* last element of rowptr si nnz */ |
| | 93 | rowptr[num-2] = nnz; |
| | 94 | |
| | 95 | /* solve with CG */ |
| | 96 | itc = solve_cg(num-2, nnz, nzval, colind, rowptr, &phi[1], &rhs[1], tol); |
| | 97 | if (itc < 0){ |
| | 98 | printf("calculation failed\n"); |
| | 99 | exit(-1); |
| | 100 | } |
| | 101 | |
| | 102 | printf("Number of Iteration=%d\n",itc); |
| | 103 | |
| | 104 | /* Output Result */ |
| | 105 | fp = fopen("res.dat","w"); |
| | 106 | if (fp == NULL){ |
| | 107 | printf("File could not create\n"); |
| | 108 | exit(-1); |
| | 109 | } |
| | 110 | |
| | 111 | for (i = 0 ; i < num ; i++){ |
| | 112 | fprintf(fp,"%e %e\n",dx * (double)i,phi[i]); |
| | 113 | } |
| | 114 | fclose(fp); |
| | 115 | |
| | 116 | /* END : Deallocate Memory */ |
| | 117 | free(phi); |
| | 118 | free(rhs); |
| | 119 | free(nzval); |
| | 120 | free(colind); |
| | 121 | free(rowptr); |
| | 122 | |
| | 123 | printf("Done\n"); |
| | 124 | } |
| | 125 | }}} |
| | 126 | |
| | 127 | [[cypress/Programming/Cg|cg.c]] |
