1 2 #include "src/mat/matimpl.h" /*I "petscmat.h" I*/ 3 4 #undef __FUNCT__ 5 #define __FUNCT__ "Mat_CheckCompressedRow" 6 /*@C 7 Mat_CheckCompressedRow - Determines whether the compressed row matrix format should be used. 8 If the format is to be used, this routine creates Mat_CompressedRow struct. 9 Compressed row format provides high performance routines by taking advantage of zero rows. 10 Supported types are MATAIJ, MATBAIJ and MATSBAIJ. 11 12 Collective 13 14 Input Parameters: 15 + A - the matrix 16 . compressedrow - pointer to the struct Mat_CompressedRow 17 . ai - row pointer used by seqaij and seqbaij 18 . mbs - number of (block) rows represented by ai 19 - ratio - ratio of (num of zero rows)/m, used to determine if the compressed row format should be used 20 21 Level: developer 22 @*/ 23 PetscErrorCode Mat_CheckCompressedRow(Mat A,Mat_CompressedRow *compressedrow,PetscInt *ai,PetscInt mbs,PetscReal ratio) 24 { 25 PetscErrorCode ierr; 26 PetscInt nrows,*cpi=PETSC_NULL,*ridx=PETSC_NULL,nz,i,row; 27 28 PetscFunctionBegin; 29 if (!compressedrow->use) PetscFunctionReturn(0); 30 if (compressedrow->checked){ 31 if (!A->same_nonzero){ 32 ierr = PetscFree(compressedrow->i);CHKERRQ(ierr); 33 compressedrow->rindex = PETSC_NULL; 34 PetscLogInfo(A,"Mat_CheckCompressedRow: Mat structure might be changed. Free memory and recheck.\n"); 35 } else if (compressedrow->i == PETSC_NULL) { 36 /* Don't know why this occures. For safe, recheck. */ 37 PetscLogInfo(A,"Mat_CheckCompressedRow: compressedrow.checked, but compressedrow.i==null. Recheck.\n"); 38 } else { /* use compressedrow, checked, A->same_nonzero = PETSC_TRUE. Skip check */ 39 PetscLogInfo(A,"Mat_CheckCompressedRow: Skip check. m: %d, n: %d,M: %d, N: %d,nrows: %d, ii: %p, type: %s\n",A->m,A->n,A->M,A->N,compressedrow->nrows,compressedrow->i,A->type_name); 40 PetscFunctionReturn(0); 41 } 42 } 43 compressedrow->checked = PETSC_TRUE; 44 45 /* compute number of zero rows */ 46 nrows = 0; 47 for (i=0; i<mbs; i++){ /* for each row */ 48 nz = ai[i+1] - ai[i]; /* number of nonzeros */ 49 if (nz == 0) nrows++; 50 } 51 /* if a large number of zero rows is found, use compressedrow data structure */ 52 if (nrows < ratio*mbs) { 53 compressedrow->use = PETSC_FALSE; 54 PetscLogInfo(A,"Mat_CheckCompressedRow: Found the ratio (num_zerorows %d)/(num_localrows %d) < %g. Do not use CompressedRow routines.\n",nrows,mbs,ratio); 55 } else { 56 compressedrow->use = PETSC_TRUE; 57 PetscLogInfo(A,"Mat_CheckCompressedRow: Found the ratio (num_zerorows %d)/(num_localrows %d) > %g. Use CompressedRow routines.\n",nrows,mbs,ratio); 58 59 /* set compressed row format */ 60 nrows = mbs - nrows; /* num of non-zero rows */ 61 ierr = PetscMalloc((2*nrows+1)*sizeof(PetscInt),&cpi);CHKERRQ(ierr); 62 ridx = cpi + nrows + 1; 63 row = 0; 64 cpi[0] = 0; 65 for (i=0; i<mbs; i++){ 66 nz = ai[i+1] - ai[i]; 67 if (nz == 0) continue; 68 cpi[row+1] = ai[i+1]; /* compressed row pointer */ 69 ridx[row++] = i; /* compressed row local index */ 70 } 71 compressedrow->nrows = nrows; 72 compressedrow->i = cpi; 73 compressedrow->rindex = ridx; 74 } 75 76 PetscFunctionReturn(0); 77 } 78