1: #define PETSCMAT_DLL

  3: /* 
  4:    This file contains simple binary read/write routines for matrices.
  5:  */

 7:  #include include/private/matimpl.h
 8:  #include petscsys.h

 12: /*@C
 13:    MatLoad - Loads a matrix that has been stored in binary format
 14:    with MatView().  The matrix format is determined from the options database.
 15:    Generates a parallel MPI matrix if the communicator has more than one
 16:    processor.  The default matrix type is AIJ.

 18:    Collective on PetscViewer

 20:    Input Parameters:
 21: +  viewer - binary file viewer, created with PetscViewerBinaryOpen()
 22: -  outtype - type of matrix desired, for example MATSEQAIJ,
 23:              MATMPIROWBS, etc.  See types in petsc/include/petscmat.h.

 25:    Output Parameters:
 26: .  newmat - new matrix

 28:    Basic Options Database Keys:
 29: +    -matload_type seqaij   - AIJ type
 30: .    -matload_type mpiaij   - parallel AIJ type
 31: .    -matload_type seqbaij  - block AIJ type
 32: .    -matload_type mpibaij  - parallel block AIJ type
 33: .    -matload_type seqsbaij - block symmetric AIJ type
 34: .    -matload_type mpisbaij - parallel block symmetric AIJ type
 35: .    -matload_type seqbdiag - block diagonal type
 36: .    -matload_type mpibdiag - parallel block diagonal type
 37: .    -matload_type mpirowbs - parallel rowbs type
 38: .    -matload_type seqdense - dense type
 39: .    -matload_type mpidense - parallel dense type
 40: -    -matload_symmetric - matrix in file is symmetric

 42:    More Options Database Keys:
 43:    Used with block matrix formats (MATSEQBAIJ, MATMPIBDIAG, ...) to specify
 44:    block size
 45: .    -matload_block_size <bs>

 47:    Used to specify block diagonal numbers for MATSEQBDIAG and MATMPIBDIAG formats
 48: .    -matload_bdiag_diags <s1,s2,s3,...>

 50:    Level: beginner

 52:    Notes:
 53:    MatLoad() automatically loads into the options database any options
 54:    given in the file filename.info where filename is the name of the file
 55:    that was passed to the PetscViewerBinaryOpen(). The options in the info
 56:    file will be ignored if you use the -viewer_binary_skip_info option.

 58:    In parallel, each processor can load a subset of rows (or the
 59:    entire matrix).  This routine is especially useful when a large
 60:    matrix is stored on disk and only part of it existsis desired on each
 61:    processor.  For example, a parallel solver may access only some of
 62:    the rows from each processor.  The algorithm used here reads
 63:    relatively small blocks of data rather than reading the entire
 64:    matrix and then subsetting it.

 66:    Notes for advanced users:
 67:    Most users should not need to know the details of the binary storage
 68:    format, since MatLoad() and MatView() completely hide these details.
 69:    But for anyone who's interested, the standard binary matrix storage
 70:    format is

 72: $    int    MAT_FILE_COOKIE
 73: $    int    number of rows
 74: $    int    number of columns
 75: $    int    total number of nonzeros
 76: $    int    *number nonzeros in each row
 77: $    int    *column indices of all nonzeros (starting index is zero)
 78: $    PetscScalar *values of all nonzeros

 80:    PETSc automatically does the byte swapping for
 81: machines that store the bytes reversed, e.g.  DEC alpha, freebsd,
 82: linux, Windows and the paragon; thus if you write your own binary
 83: read/write routines you have to swap the bytes; see PetscBinaryRead()
 84: and PetscBinaryWrite() to see how this may be done.

 86: .keywords: matrix, load, binary, input

 88: .seealso: PetscViewerBinaryOpen(), MatView(), VecLoad()

 90:  @*/
 91: PetscErrorCode  MatLoad(PetscViewer viewer, MatType outtype,Mat *newmat)
 92: {
 93:   Mat            factory;
 95:   PetscTruth     isbinary,flg;
 96:   MPI_Comm       comm;
 97:   PetscErrorCode (*r)(PetscViewer, MatType,Mat*);
 98:   char           mtype[256];
 99:   const char     *prefix;

104:   *newmat = 0;

106:   PetscObjectGetOptionsPrefix((PetscObject)viewer,(const char **)&prefix);
107:   PetscTypeCompare((PetscObject)viewer,PETSC_VIEWER_BINARY,&isbinary);
108:   if (!isbinary) {
109:     SETERRQ(PETSC_ERR_ARG_WRONG,"Invalid viewer; open viewer with PetscViewerBinaryOpen()");
110:   }

112:   PetscOptionsGetString(prefix,"-mat_type",mtype,256,&flg);
113:   if (flg) {
114:     outtype = mtype;
115:   }
116:   PetscOptionsGetString(prefix,"-matload_type",mtype,256,&flg);
117:   if (flg) {
118:     outtype = mtype;
119:   }
120:   if (!outtype) outtype = MATAIJ;

122:   PetscObjectGetComm((PetscObject)viewer,&comm);
123:   MatCreate(comm,&factory);
124:   MatSetSizes(factory,0,0,0,0);
125:   MatSetType(factory,outtype);
126:   r = factory->ops->load;
127:   MatDestroy(factory);
128:   if (!r) SETERRQ1(PETSC_ERR_SUP,"MatLoad is not supported for type: %s",outtype);

131:   (*r)(viewer,outtype,newmat);

134:   PetscOptionsHasName(prefix,"-matload_symmetric",&flg);
135:   if (flg) {
136:     MatSetOption(*newmat,MAT_SYMMETRIC);
137:     MatSetOption(*newmat,MAT_SYMMETRY_ETERNAL);
138:   }
139:   return(0);
140: }