1 2 #include <../src/mat/impls/aij/seq/aij.h> 3 4 /* 5 MatToSymmetricIJ_SeqAIJ - Convert a (generally nonsymmetric) sparse AIJ matrix 6 to IJ format (ignore the "A" part) Allocates the space needed. Uses only 7 the lower triangular part of the matrix. 8 9 Description: 10 Take the data in the row-oriented sparse storage and build the 11 IJ data for the Matrix. Return 0 on success,row + 1 on failure 12 at that row. Produces the ij for a symmetric matrix by using 13 the lower triangular part of the matrix if lower_triangular is PETSC_TRUE; 14 it uses the upper triangular otherwise. 15 16 Input Parameters: 17 . Matrix - matrix to convert 18 . lower_triangular - symmetrize the lower triangular part 19 . shiftin - the shift for the original matrix (0 or 1) 20 . shiftout - the shift required for the ordering routine (0 or 1) 21 22 Output Parameters: 23 . ia - ia part of IJ representation (row information) 24 . ja - ja part (column indices) 25 26 Notes: 27 Both ia and ja may be freed with PetscFree(); 28 This routine is provided for ordering routines that require a 29 symmetric structure. It is required since those routines call 30 SparsePak routines that expect a symmetric matrix. 31 */ 32 PetscErrorCode MatToSymmetricIJ_SeqAIJ(PetscInt m,PetscInt *ai,PetscInt *aj,PetscBool lower_triangular,PetscInt shiftin,PetscInt shiftout,PetscInt **iia,PetscInt **jja) 33 { 34 PetscErrorCode ierr; 35 PetscInt *work,*ia,*ja,*j,i,nz,row,col; 36 37 PetscFunctionBegin; 38 /* allocate space for row pointers */ 39 ierr = PetscMalloc1(m+1,&ia);CHKERRQ(ierr); 40 *iia = ia; 41 ierr = PetscMemzero(ia,(m+1)*sizeof(PetscInt));CHKERRQ(ierr); 42 ierr = PetscMalloc1(m+1,&work);CHKERRQ(ierr); 43 44 /* determine the number of columns in each row */ 45 ia[0] = shiftout; 46 for (row = 0; row < m; row++) { 47 nz = ai[row+1] - ai[row]; 48 j = aj + ai[row] + shiftin; 49 while (nz--) { 50 col = *j++ + shiftin; 51 if (lower_triangular) { 52 if (col > row) break; 53 } else { 54 if (col < row) break; 55 } 56 if (col != row) ia[row+1]++; 57 ia[col+1]++; 58 } 59 } 60 61 /* shiftin ia[i] to point to next row */ 62 for (i=1; i<m+1; i++) { 63 row = ia[i-1]; 64 ia[i] += row; 65 work[i-1] = row - shiftout; 66 } 67 68 /* allocate space for column pointers */ 69 nz = ia[m] + (!shiftin); 70 ierr = PetscMalloc1(nz,&ja);CHKERRQ(ierr); 71 *jja = ja; 72 73 /* loop over lower triangular part putting into ja */ 74 for (row = 0; row < m; row++) { 75 nz = ai[row+1] - ai[row]; 76 j = aj + ai[row] + shiftin; 77 while (nz--) { 78 col = *j++ + shiftin; 79 if (lower_triangular) { 80 if (col > row) break; 81 } else { 82 if (col < row) break; 83 } 84 if (col != row) ja[work[col]++] = row + shiftout; 85 ja[work[row]++] = col + shiftout; 86 } 87 } 88 ierr = PetscFree(work);CHKERRQ(ierr); 89 PetscFunctionReturn(0); 90 } 91 92 93 94