1 #define PETSCMAT_DLL 2 3 #include "../src/mat/impls/baij/seq/baij.h" 4 #include "../src/mat/impls/sbaij/seq/sbaij.h" 5 6 /* 7 This function is used before applying a 8 symmetric reordering to matrix A that is 9 in SBAIJ format. 10 11 The permutation is assumed to be symmetric, i.e., 12 P = P^T (= inv(P)), 13 so the permuted matrix P*A*inv(P)=P*A*P^T is ensured to be symmetric. 14 - a wrong assumption! This code needs rework! -- Hong 15 16 The function is modified from sro.f of YSMP. The description from YSMP: 17 C THE NONZERO ENTRIES OF THE MATRIX M ARE ASSUMED TO BE STORED 18 C SYMMETRICALLY IN (IA,JA,A) FORMAT (I.E., NOT BOTH M(I,J) AND M(J,I) 19 C ARE STORED IF I NE J). 20 C 21 C SRO DOES NOT REARRANGE THE ORDER OF THE ROWS, BUT DOES MOVE 22 C NONZEROES FROM ONE ROW TO ANOTHER TO ENSURE THAT IF M(I,J) WILL BE 23 C IN THE UPPER TRIANGLE OF M WITH RESPECT TO THE NEW ORDERING, THEN 24 C M(I,J) IS STORED IN ROW I (AND THUS M(J,I) IS NOT STORED); WHEREAS 25 C IF M(I,J) WILL BE IN THE STRICT LOWER TRIANGLE OF M, THEN M(J,I) IS 26 C STORED IN ROW J (AND THUS M(I,J) IS NOT STORED). 27 28 29 -- output: new index set (inew, jnew) for A and a map a2anew that maps 30 values a to anew, such that all 31 nonzero A_(perm(i),iperm(k)) will be stored in the upper triangle. 32 Note: matrix A is not permuted by this function! 33 */ 34 #undef __FUNCT__ 35 #define __FUNCT__ "MatReorderingSeqSBAIJ" 36 PetscErrorCode PETSCMAT_DLLEXPORT MatReorderingSeqSBAIJ(Mat A,IS perm) 37 { 38 Mat_SeqSBAIJ *a=(Mat_SeqSBAIJ *)A->data; 39 PetscErrorCode ierr; 40 const PetscInt mbs=a->mbs,*rip,*riip; 41 PetscInt *ai,*aj,*r; 42 PetscInt *nzr,nz,jmin,jmax,j,k,ajk,i; 43 IS iperm; /* inverse of perm */ 44 45 PetscFunctionBegin; 46 if (!mbs) PetscFunctionReturn(0); 47 SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"Matrix reordering is not supported for sbaij matrix. Use aij format"); 48 ierr = ISGetIndices(perm,&rip);CHKERRQ(ierr); 49 50 ierr = ISInvertPermutation(perm,PETSC_DECIDE,&iperm);CHKERRQ(ierr); 51 ierr = ISGetIndices(iperm,&riip);CHKERRQ(ierr); 52 53 for (i=0; i<mbs; i++) { 54 if (rip[i] != riip[i]) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_INCOMP,"Non-symmetric permutation, use symmetric permutation for symmetric matrices"); 55 } 56 ierr = ISRestoreIndices(iperm,&riip);CHKERRQ(ierr); 57 ierr = ISDestroy(iperm);CHKERRQ(ierr); 58 59 if (!a->inew){ 60 ierr = PetscMalloc2(mbs+1,PetscInt,&ai, 2*a->i[mbs],PetscInt,&aj);CHKERRQ(ierr); 61 } else { 62 ai = a->inew; aj = a->jnew; 63 } 64 ierr = PetscMemcpy(ai,a->i,(mbs+1)*sizeof(PetscInt));CHKERRQ(ierr); 65 ierr = PetscMemcpy(aj,a->j,(a->i[mbs])*sizeof(PetscInt));CHKERRQ(ierr); 66 67 /* 68 Phase 1: Find row index r in which to store each nonzero. 69 Initialize count of nonzeros to be stored in each row (nzr). 70 At the end of this phase, a nonzero a(*,*)=a(r(),aj()) 71 s.t. a(perm(r),perm(aj)) will fall into upper triangle part. 72 */ 73 74 ierr = PetscMalloc(mbs*sizeof(PetscInt),&nzr);CHKERRQ(ierr); 75 ierr = PetscMalloc(ai[mbs]*sizeof(PetscInt),&r);CHKERRQ(ierr); 76 for (i=0; i<mbs; i++) nzr[i] = 0; 77 for (i=0; i<ai[mbs]; i++) r[i] = 0; 78 79 /* for each nonzero element */ 80 for (i=0; i<mbs; i++){ 81 nz = ai[i+1] - ai[i]; 82 j = ai[i]; 83 /* printf("nz = %d, j=%d\n",nz,j); */ 84 while (nz--){ 85 /* --- find row (=r[j]) and column (=aj[j]) in which to store a[j] ...*/ 86 k = aj[j]; /* col. index */ 87 /* printf("nz = %d, k=%d\n", nz,k); */ 88 /* for entry that will be permuted into lower triangle, swap row and col. index */ 89 if (rip[k] < rip[i]) aj[j] = i; 90 else k = i; 91 92 r[j] = k; j++; 93 nzr[k] ++; /* increment count of nonzeros in that row */ 94 } 95 } 96 97 /* Phase 2: Find new ai and permutation to apply to (aj,a). 98 Determine pointers (r) to delimit rows in permuted (aj,a). 99 Note: r is different from r used in phase 1. 100 At the end of this phase, (aj[j],a[j]) will be stored in 101 (aj[r(j)],a[r(j)]). 102 */ 103 for (i=0; i<mbs; i++){ 104 ai[i+1] = ai[i] + nzr[i]; 105 nzr[i] = ai[i+1]; 106 } 107 108 /* determine where each (aj[j], a[j]) is stored in new (aj,a) 109 for each nonzero element (in reverse order) */ 110 jmin = ai[0]; jmax = ai[mbs]; 111 nz = jmax - jmin; 112 j = jmax-1; 113 while (nz--){ 114 i = r[j]; /* row value */ 115 if (aj[j] == i) r[j] = ai[i]; /* put diagonal nonzero at beginning of row */ 116 else { /* put off-diagonal nonzero in last unused location in row */ 117 nzr[i]--; r[j] = nzr[i]; 118 } 119 j--; 120 } 121 122 a->a2anew = aj + ai[mbs]; 123 ierr = PetscMemcpy(a->a2anew,r,ai[mbs]*sizeof(PetscInt));CHKERRQ(ierr); 124 125 /* Phase 3: permute (aj,a) to upper triangular form (wrt new ordering) */ 126 for (j=jmin; j<jmax; j++){ 127 while (r[j] != j){ 128 k = r[j]; r[j] = r[k]; r[k] = k; 129 ajk = aj[k]; aj[k] = aj[j]; aj[j] = ajk; 130 /* ak = aa[k]; aa[k] = aa[j]; aa[j] = ak; */ 131 } 132 } 133 ierr= ISRestoreIndices(perm,&rip);CHKERRQ(ierr); 134 135 a->inew = ai; 136 a->jnew = aj; 137 138 if (a->row) { 139 ierr = ISDestroy(a->row);CHKERRQ(ierr); 140 } 141 if (a->icol) { 142 ierr = ISDestroy(a->icol);CHKERRQ(ierr); 143 } 144 ierr = PetscObjectReference((PetscObject)perm);CHKERRQ(ierr); 145 if (a->row) { ierr = ISDestroy(a->row);CHKERRQ(ierr); } 146 a->row = perm; 147 ierr = PetscObjectReference((PetscObject)perm);CHKERRQ(ierr); 148 if (a->icol) { ierr = ISDestroy(a->icol);CHKERRQ(ierr); } 149 a->icol = perm; 150 151 ierr = PetscFree(nzr);CHKERRQ(ierr); 152 ierr = PetscFree(r);CHKERRQ(ierr); 153 154 PetscFunctionReturn(0); 155 } 156 157 158