1 #define PETSCMAT_DLL 2 3 #include "../src/mat/impls/baij/seq/baij.h" 4 #include "../src/mat/impls/sbaij/seq/sbaij.h" 5 #include "petscsys.h" 6 7 /* 8 This function is used before applying a 9 symmetric reordering to matrix A that is 10 in SBAIJ format. 11 12 The permutation is assumed to be symmetric, i.e., 13 P = P^T (= inv(P)), 14 so the permuted matrix P*A*inv(P)=P*A*P^T is ensured to be symmetric. 15 - a wrong assumption! This code needs rework! -- Hong 16 17 The function is modified from sro.f of YSMP. The description from YSMP: 18 C THE NONZERO ENTRIES OF THE MATRIX M ARE ASSUMED TO BE STORED 19 C SYMMETRICALLY IN (IA,JA,A) FORMAT (I.E., NOT BOTH M(I,J) AND M(J,I) 20 C ARE STORED IF I NE J). 21 C 22 C SRO DOES NOT REARRANGE THE ORDER OF THE ROWS, BUT DOES MOVE 23 C NONZEROES FROM ONE ROW TO ANOTHER TO ENSURE THAT IF M(I,J) WILL BE 24 C IN THE UPPER TRIANGLE OF M WITH RESPECT TO THE NEW ORDERING, THEN 25 C M(I,J) IS STORED IN ROW I (AND THUS M(J,I) IS NOT STORED); WHEREAS 26 C IF M(I,J) WILL BE IN THE STRICT LOWER TRIANGLE OF M, THEN M(J,I) IS 27 C STORED IN ROW J (AND THUS M(I,J) IS NOT STORED). 28 29 30 -- output: new index set (inew, jnew) for A and a map a2anew that maps 31 values a to anew, such that all 32 nonzero A_(perm(i),iperm(k)) will be stored in the upper triangle. 33 Note: matrix A is not permuted by this function! 34 */ 35 #undef __FUNCT__ 36 #define __FUNCT__ "MatReorderingSeqSBAIJ" 37 PetscErrorCode PETSCMAT_DLLEXPORT MatReorderingSeqSBAIJ(Mat A,IS perm) 38 { 39 Mat_SeqSBAIJ *a=(Mat_SeqSBAIJ *)A->data; 40 PetscErrorCode ierr; 41 const PetscInt mbs=a->mbs,*rip,*riip; 42 PetscInt *ai,*aj,*r; 43 PetscInt *nzr,nz,jmin,jmax,j,k,ajk,i; 44 IS iperm; /* inverse of perm */ 45 46 PetscFunctionBegin; 47 if (!mbs) PetscFunctionReturn(0); 48 SETERRQ(PETSC_ERR_SUP,"Matrix reordering is not supported for sbaij matrix. Use aij format"); 49 ierr = ISGetIndices(perm,&rip);CHKERRQ(ierr); 50 51 ierr = ISInvertPermutation(perm,PETSC_DECIDE,&iperm);CHKERRQ(ierr); 52 ierr = ISGetIndices(iperm,&riip);CHKERRQ(ierr); 53 54 for (i=0; i<mbs; i++) { 55 if (rip[i] != riip[i]) SETERRQ(PETSC_ERR_ARG_INCOMP,"Non-symmetric permutation, use symmetric permutation for symmetric matrices"); 56 } 57 ierr = ISRestoreIndices(iperm,&riip);CHKERRQ(ierr); 58 ierr = ISDestroy(iperm);CHKERRQ(ierr); 59 60 if (!a->inew){ 61 ierr = PetscMalloc((mbs+1 + 2*(a->i[mbs]))*sizeof(PetscInt),&ai);CHKERRQ(ierr); 62 aj = ai + mbs+1; 63 } else { 64 ai = a->inew; aj = a->jnew; 65 } 66 ierr = PetscMemcpy(ai,a->i,(mbs+1)*sizeof(PetscInt));CHKERRQ(ierr); 67 ierr = PetscMemcpy(aj,a->j,(a->i[mbs])*sizeof(PetscInt));CHKERRQ(ierr); 68 69 /* 70 Phase 1: Find row index r in which to store each nonzero. 71 Initialize count of nonzeros to be stored in each row (nzr). 72 At the end of this phase, a nonzero a(*,*)=a(r(),aj()) 73 s.t. a(perm(r),perm(aj)) will fall into upper triangle part. 74 */ 75 76 ierr = PetscMalloc(mbs*sizeof(PetscInt),&nzr);CHKERRQ(ierr); 77 ierr = PetscMalloc(ai[mbs]*sizeof(PetscInt),&r);CHKERRQ(ierr); 78 for (i=0; i<mbs; i++) nzr[i] = 0; 79 for (i=0; i<ai[mbs]; i++) r[i] = 0; 80 81 /* for each nonzero element */ 82 for (i=0; i<mbs; i++){ 83 nz = ai[i+1] - ai[i]; 84 j = ai[i]; 85 /* printf("nz = %d, j=%d\n",nz,j); */ 86 while (nz--){ 87 /* --- find row (=r[j]) and column (=aj[j]) in which to store a[j] ...*/ 88 k = aj[j]; /* col. index */ 89 /* printf("nz = %d, k=%d\n", nz,k); */ 90 /* for entry that will be permuted into lower triangle, swap row and col. index */ 91 if (rip[k] < rip[i]) aj[j] = i; 92 else k = i; 93 94 r[j] = k; j++; 95 nzr[k] ++; /* increment count of nonzeros in that row */ 96 } 97 } 98 99 /* Phase 2: Find new ai and permutation to apply to (aj,a). 100 Determine pointers (r) to delimit rows in permuted (aj,a). 101 Note: r is different from r used in phase 1. 102 At the end of this phase, (aj[j],a[j]) will be stored in 103 (aj[r(j)],a[r(j)]). 104 */ 105 for (i=0; i<mbs; i++){ 106 ai[i+1] = ai[i] + nzr[i]; 107 nzr[i] = ai[i+1]; 108 } 109 110 /* determine where each (aj[j], a[j]) is stored in new (aj,a) 111 for each nonzero element (in reverse order) */ 112 jmin = ai[0]; jmax = ai[mbs]; 113 nz = jmax - jmin; 114 j = jmax-1; 115 while (nz--){ 116 i = r[j]; /* row value */ 117 if (aj[j] == i) r[j] = ai[i]; /* put diagonal nonzero at beginning of row */ 118 else { /* put off-diagonal nonzero in last unused location in row */ 119 nzr[i]--; r[j] = nzr[i]; 120 } 121 j--; 122 } 123 124 a->a2anew = aj + ai[mbs]; 125 ierr = PetscMemcpy(a->a2anew,r,ai[mbs]*sizeof(PetscInt));CHKERRQ(ierr); 126 127 /* Phase 3: permute (aj,a) to upper triangular form (wrt new ordering) */ 128 for (j=jmin; j<jmax; j++){ 129 while (r[j] != j){ 130 k = r[j]; r[j] = r[k]; r[k] = k; 131 ajk = aj[k]; aj[k] = aj[j]; aj[j] = ajk; 132 /* ak = aa[k]; aa[k] = aa[j]; aa[j] = ak; */ 133 } 134 } 135 ierr= ISRestoreIndices(perm,&rip);CHKERRQ(ierr); 136 137 a->inew = ai; 138 a->jnew = aj; 139 140 if (a->row) { 141 ierr = ISDestroy(a->row);CHKERRQ(ierr); 142 } 143 if (a->icol) { 144 ierr = ISDestroy(a->icol);CHKERRQ(ierr); 145 } 146 ierr = PetscObjectReference((PetscObject)perm);CHKERRQ(ierr); 147 if (a->row) { ierr = ISDestroy(a->row);CHKERRQ(ierr); } 148 a->row = perm; 149 ierr = PetscObjectReference((PetscObject)perm);CHKERRQ(ierr); 150 if (a->icol) { ierr = ISDestroy(a->icol);CHKERRQ(ierr); } 151 a->icol = perm; 152 153 ierr = PetscFree(nzr);CHKERRQ(ierr); 154 ierr = PetscFree(r);CHKERRQ(ierr); 155 156 PetscFunctionReturn(0); 157 } 158 159 160