1*29bbc08cSBarry Smith /*$Id: getcolv.c,v 1.17 2000/09/13 03:11:32 bsmith Exp bsmith $*/ 20925cdddSBarry Smith 3e090d566SSatish Balay #include "src/mat/matimpl.h" /*I "petscmat.h" I*/ 40925cdddSBarry Smith 50925cdddSBarry Smith #undef __FUNC__ 6b2863d3aSBarry Smith #define __FUNC__ /*<a name=""></a>*/"MatGetColumnVector" 70925cdddSBarry Smith /*@ 882bf6240SBarry Smith MatGetColumnVector - Gets the values from a given column of a matrix. 90925cdddSBarry Smith 1072257631SBarry Smith Not Collective 11fee21e36SBarry Smith 1298a79cdbSBarry Smith Input Parameters: 135ed6d96aSBarry Smith + A - the matrix 145ed6d96aSBarry Smith . yy - the vector 155ed6d96aSBarry Smith - c - the column requested (in global numbering) 1698a79cdbSBarry Smith 1715091d37SBarry Smith Level: advanced 1815091d37SBarry Smith 1982bf6240SBarry Smith Contributed by: Denis Vanderstraeten 200925cdddSBarry Smith 2182bf6240SBarry Smith .keywords: matrix, column, get 220925cdddSBarry Smith 2315091d37SBarry Smith .seealso: MatGetRow(), MatGetDiagonal() 2415091d37SBarry Smith 250925cdddSBarry Smith @*/ 2682bf6240SBarry Smith int MatGetColumnVector(Mat A,Vec yy,int col) 270925cdddSBarry Smith { 2882bf6240SBarry Smith Scalar *y,*v,zero = 0.0; 29b48991e4SBarry Smith int ierr,i,j,nz,*idx,N,Rs,Re,rs,re,size; 30011b8408SBarry Smith MPI_Comm comm; 310925cdddSBarry Smith 320925cdddSBarry Smith PetscFunctionBegin; 3382bf6240SBarry Smith PetscValidHeaderSpecific(A,MAT_COOKIE); 3482bf6240SBarry Smith PetscValidHeaderSpecific(yy,VEC_COOKIE); 350925cdddSBarry Smith 36*29bbc08cSBarry Smith if (col < 0) SETERRQ1(1,"Requested negative column: %d",col); 37011b8408SBarry Smith ierr = MatGetSize(A,PETSC_NULL,&N);CHKERRQ(ierr); 38*29bbc08cSBarry Smith if (col >= N) SETERRQ2(1,"Requested column %d larger than number columns in matrix %d",col,N); 390925cdddSBarry Smith 4082bf6240SBarry Smith ierr = MatGetOwnershipRange(A,&Rs,&Re);CHKERRQ(ierr); 41011b8408SBarry Smith 42011b8408SBarry Smith ierr = PetscObjectGetComm((PetscObject)yy,&comm);CHKERRQ(ierr); 43011b8408SBarry Smith ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr); 4482bf6240SBarry Smith ierr = VecGetOwnershipRange(yy,&rs,&re);CHKERRQ(ierr); 45*29bbc08cSBarry Smith if (Rs != rs || Re != re) SETERRQ4(1,"Matrix %d %d does not have same ownership range (size) as vector %d %d",Rs,Re,rs,re); 4682bf6240SBarry Smith 4782bf6240SBarry Smith ierr = VecSet(&zero,yy);CHKERRQ(ierr); 4882bf6240SBarry Smith ierr = VecGetArray(yy,&y);CHKERRQ(ierr); 4982bf6240SBarry Smith 5082bf6240SBarry Smith for (i=Rs; i<Re; i++) { 5182bf6240SBarry Smith ierr = MatGetRow(A,i,&nz,&idx,&v);CHKERRQ(ierr); 5282bf6240SBarry Smith if (nz && idx[0] <= col) { 5382bf6240SBarry Smith /* 5482bf6240SBarry Smith Should use faster search here 5582bf6240SBarry Smith */ 5682bf6240SBarry Smith for (j=0; j<nz; j++) { 5782bf6240SBarry Smith if (idx[j] >= col) { 5882bf6240SBarry Smith if (idx[j] == col) y[i-rs] = v[j]; 5982bf6240SBarry Smith break; 600925cdddSBarry Smith } 610925cdddSBarry Smith } 620925cdddSBarry Smith } 6382bf6240SBarry Smith ierr = MatRestoreRow(A,i,&nz,&idx,&v);CHKERRQ(ierr); 640925cdddSBarry Smith } 650925cdddSBarry Smith 6682bf6240SBarry Smith ierr = VecRestoreArray(yy,&y);CHKERRQ(ierr); 670925cdddSBarry Smith PetscFunctionReturn(0); 680925cdddSBarry Smith } 69