2: #include <petsc-private/matimpl.h>          /*I "petscmat.h" I*/

  4: typedef struct {
  5:   Mat A;
  6: } Mat_Transpose;

 10: PetscErrorCode MatMult_Transpose(Mat N,Vec x,Vec y)
 11: {
 12:   Mat_Transpose  *Na = (Mat_Transpose*)N->data;

 16:   MatMultTranspose(Na->A,x,y);
 17:   return(0);
 18: }

 22: PetscErrorCode MatMultAdd_Transpose(Mat N,Vec v1,Vec v2,Vec v3)
 23: {
 24:   Mat_Transpose  *Na = (Mat_Transpose*)N->data;

 28:   MatMultTransposeAdd(Na->A,v1,v2,v3);
 29:   return(0);
 30: }

 34: PetscErrorCode MatMultTranspose_Transpose(Mat N,Vec x,Vec y)
 35: {
 36:   Mat_Transpose  *Na = (Mat_Transpose*)N->data;

 40:   MatMult(Na->A,x,y);
 41:   return(0);
 42: }

 46: PetscErrorCode MatMultTransposeAdd_Transpose(Mat N,Vec v1,Vec v2,Vec v3)
 47: {
 48:   Mat_Transpose  *Na = (Mat_Transpose*)N->data;

 52:   MatMultAdd(Na->A,v1,v2,v3);
 53:   return(0);
 54: }

 58: PetscErrorCode MatDestroy_Transpose(Mat N)
 59: {
 60:   Mat_Transpose  *Na = (Mat_Transpose*)N->data;

 64:   MatDestroy(&Na->A);
 65:   PetscFree(N->data);
 66:   return(0);
 67: }

 71: /*@
 72:       MatCreateTranspose - Creates a new matrix object that behaves like A'

 74:    Collective on Mat

 76:    Input Parameter:
 77: .   A  - the (possibly rectangular) matrix

 79:    Output Parameter:
 80: .   N - the matrix that represents A'

 82:    Level: intermediate

 84:    Notes: The transpose A' is NOT actually formed! Rather the new matrix
 85:           object performs the matrix-vector product by using the MatMultTranspose() on
 86:           the original matrix

 88: .seealso: MatCreateNormal(), MatMult(), MatMultTranspose(), MatCreate()

 90: @*/
 91: PetscErrorCode  MatCreateTranspose(Mat A,Mat *N)
 92: {
 94:   PetscInt       m,n;
 95:   Mat_Transpose  *Na;

 98:   MatGetLocalSize(A,&m,&n);
 99:   MatCreate(PetscObjectComm((PetscObject)A),N);
100:   MatSetSizes(*N,n,m,PETSC_DECIDE,PETSC_DECIDE);
101:   PetscLayoutSetUp((*N)->rmap);
102:   PetscLayoutSetUp((*N)->cmap);
103:   PetscObjectChangeTypeName((PetscObject)*N,MATTRANSPOSEMAT);

105:   PetscNewLog(*N,&Na);
106:   (*N)->data = (void*) Na;
107:   PetscObjectReference((PetscObject)A);
108:   Na->A      = A;

110:   (*N)->ops->destroy          = MatDestroy_Transpose;
111:   (*N)->ops->mult             = MatMult_Transpose;
112:   (*N)->ops->multadd          = MatMultAdd_Transpose;
113:   (*N)->ops->multtranspose    = MatMultTranspose_Transpose;
114:   (*N)->ops->multtransposeadd = MatMultTransposeAdd_Transpose;
115:   (*N)->assembled             = PETSC_TRUE;

117:   MatSetBlockSizes(*N,PetscAbs(A->cmap->bs),PetscAbs(A->rmap->bs));
118:   MatSetUp(*N);
119:   return(0);
120: }