xref: /petsc/src/mat/impls/baij/seq/baijfact4.c (revision b0a32e0c6855ee6a6cd3495fa7da12ea9885bc5d)
1*b0a32e0cSBarry Smith /*$Id: baijfact4.c,v 1.1 2001/01/06 15:35:15 bsmith Exp bsmith $*/
283287d42SBarry Smith /*
383287d42SBarry Smith     Factorization code for BAIJ format.
483287d42SBarry Smith */
583287d42SBarry Smith #include "src/mat/impls/baij/seq/baij.h"
683287d42SBarry Smith #include "src/vec/vecimpl.h"
783287d42SBarry Smith #include "src/inline/ilu.h"
883287d42SBarry Smith 
983287d42SBarry Smith /* ----------------------------------------------------------- */
1083287d42SBarry Smith #undef __FUNC__
11*b0a32e0cSBarry Smith #define __FUNC__ "MatLUFactorNumeric_SeqBAIJ_N"
1283287d42SBarry Smith int MatLUFactorNumeric_SeqBAIJ_N(Mat A,Mat *B)
1383287d42SBarry Smith {
1483287d42SBarry Smith   Mat                C = *B;
1583287d42SBarry Smith   Mat_SeqBAIJ        *a = (Mat_SeqBAIJ*)A->data,*b = (Mat_SeqBAIJ *)C->data;
1683287d42SBarry Smith   IS                 isrow = b->row,isicol = b->icol;
1783287d42SBarry Smith   int                *r,*ic,ierr,i,j,n = a->mbs,*bi = b->i,*bj = b->j;
1883287d42SBarry Smith   int                *ajtmpold,*ajtmp,nz,row,bslog,*ai=a->i,*aj=a->j,k,flg;
1983287d42SBarry Smith   int                *diag_offset=b->diag,diag,bs=a->bs,bs2 = a->bs2,*v_pivots,*pj;
2083287d42SBarry Smith   MatScalar          *ba = b->a,*aa = a->a,*pv,*v,*rtmp,*multiplier,*v_work,*pc,*w;
2183287d42SBarry Smith 
2283287d42SBarry Smith   PetscFunctionBegin;
2383287d42SBarry Smith   ierr = ISGetIndices(isrow,&r);CHKERRQ(ierr);
2483287d42SBarry Smith   ierr = ISGetIndices(isicol,&ic);CHKERRQ(ierr);
25*b0a32e0cSBarry Smith ierr = PetscMalloc(bs2*(n+1)*sizeof(MatScalar),&  rtmp );CHKERRQ(ierr);
2683287d42SBarry Smith   ierr = PetscMemzero(rtmp,bs2*(n+1)*sizeof(MatScalar));CHKERRQ(ierr);
2783287d42SBarry Smith   /* generate work space needed by dense LU factorization */
28*b0a32e0cSBarry Smith   v_work     = (MatScalar*)PetscMalloc(bs*sizeof(int) + (bs+bs2)*sizeof(MatScalar));CHKERRQ(ierr);
2983287d42SBarry Smith   multiplier = v_work + bs;
3083287d42SBarry Smith   v_pivots   = (int*)(multiplier + bs2);
3183287d42SBarry Smith 
3283287d42SBarry Smith   /* flops in while loop */
3383287d42SBarry Smith   bslog = 2*bs*bs2;
3483287d42SBarry Smith 
3583287d42SBarry Smith   for (i=0; i<n; i++) {
3683287d42SBarry Smith     nz    = bi[i+1] - bi[i];
3783287d42SBarry Smith     ajtmp = bj + bi[i];
3883287d42SBarry Smith     for  (j=0; j<nz; j++) {
3983287d42SBarry Smith       ierr = PetscMemzero(rtmp+bs2*ajtmp[j],bs2*sizeof(MatScalar));CHKERRQ(ierr);
4083287d42SBarry Smith     }
4183287d42SBarry Smith     /* load in initial (unfactored row) */
4283287d42SBarry Smith     nz       = ai[r[i]+1] - ai[r[i]];
4383287d42SBarry Smith     ajtmpold = aj + ai[r[i]];
4483287d42SBarry Smith     v        = aa + bs2*ai[r[i]];
4583287d42SBarry Smith     for (j=0; j<nz; j++) {
4683287d42SBarry Smith       ierr = PetscMemcpy(rtmp+bs2*ic[ajtmpold[j]],v+bs2*j,bs2*sizeof(MatScalar));CHKERRQ(ierr);
4783287d42SBarry Smith     }
4883287d42SBarry Smith     row = *ajtmp++;
4983287d42SBarry Smith     while (row < i) {
5083287d42SBarry Smith       pc = rtmp + bs2*row;
5183287d42SBarry Smith /*      if (*pc) { */
5283287d42SBarry Smith       for (flg=0,k=0; k<bs2; k++) { if (pc[k]!=0.0) { flg = 1; break; }}
5383287d42SBarry Smith       if (flg) {
5483287d42SBarry Smith         pv = ba + bs2*diag_offset[row];
5583287d42SBarry Smith         pj = bj + diag_offset[row] + 1;
5683287d42SBarry Smith         Kernel_A_gets_A_times_B(bs,pc,pv,multiplier);
5783287d42SBarry Smith         nz = bi[row+1] - diag_offset[row] - 1;
5883287d42SBarry Smith         pv += bs2;
5983287d42SBarry Smith         for (j=0; j<nz; j++) {
6083287d42SBarry Smith           Kernel_A_gets_A_minus_B_times_C(bs,rtmp+bs2*pj[j],pc,pv+bs2*j);
6183287d42SBarry Smith         }
62*b0a32e0cSBarry Smith         PetscLogFlops(bslog*(nz+1)-bs);
6383287d42SBarry Smith       }
6483287d42SBarry Smith         row = *ajtmp++;
6583287d42SBarry Smith     }
6683287d42SBarry Smith     /* finished row so stick it into b->a */
6783287d42SBarry Smith     pv = ba + bs2*bi[i];
6883287d42SBarry Smith     pj = bj + bi[i];
6983287d42SBarry Smith     nz = bi[i+1] - bi[i];
7083287d42SBarry Smith     for (j=0; j<nz; j++) {
7183287d42SBarry Smith       ierr = PetscMemcpy(pv+bs2*j,rtmp+bs2*pj[j],bs2*sizeof(MatScalar));CHKERRQ(ierr);
7283287d42SBarry Smith     }
7383287d42SBarry Smith     diag = diag_offset[i] - bi[i];
7483287d42SBarry Smith     /* invert diagonal block */
7583287d42SBarry Smith     w = pv + bs2*diag;
7683287d42SBarry Smith     Kernel_A_gets_inverse_A(bs,w,v_pivots,v_work);
7783287d42SBarry Smith   }
7883287d42SBarry Smith 
7983287d42SBarry Smith   ierr = PetscFree(rtmp);CHKERRQ(ierr);
8083287d42SBarry Smith   ierr = PetscFree(v_work);CHKERRQ(ierr);
8183287d42SBarry Smith   ierr = ISRestoreIndices(isicol,&ic);CHKERRQ(ierr);
8283287d42SBarry Smith   ierr = ISRestoreIndices(isrow,&r);CHKERRQ(ierr);
8383287d42SBarry Smith   C->factor = FACTOR_LU;
8483287d42SBarry Smith   C->assembled = PETSC_TRUE;
85*b0a32e0cSBarry Smith   PetscLogFlops(1.3333*bs*bs2*b->mbs); /* from inverting diagonal blocks */
8683287d42SBarry Smith   PetscFunctionReturn(0);
8783287d42SBarry Smith }
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