1 2 #include <petsc/private/matimpl.h> /*I "petscmat.h" I*/ 3 4 typedef struct { 5 Mat A; /* sparse matrix */ 6 Mat U,V; /* dense tall-skinny matrices */ 7 Vec c; /* sequential vector containing the diagonal of C */ 8 Vec work1,work2; /* sequential vectors that hold partial products */ 9 PetscMPIInt nwork; /* length of work vectors */ 10 Vec xl,yl; /* auxiliary sequential vectors for matmult operation */ 11 } Mat_LRC; 12 13 PetscErrorCode MatMult_LRC(Mat N,Vec x,Vec y) 14 { 15 Mat_LRC *Na = (Mat_LRC*)N->data; 16 Mat Uloc,Vloc; 17 PetscErrorCode ierr; 18 PetscScalar *w1,*w2; 19 const PetscScalar *a; 20 21 PetscFunctionBegin; 22 ierr = VecGetArrayRead(x,&a);CHKERRQ(ierr); 23 ierr = VecPlaceArray(Na->xl,a);CHKERRQ(ierr); 24 ierr = VecGetLocalVector(y,Na->yl);CHKERRQ(ierr); 25 ierr = MatDenseGetLocalMatrix(Na->U,&Uloc);CHKERRQ(ierr); 26 ierr = MatDenseGetLocalMatrix(Na->V,&Vloc);CHKERRQ(ierr); 27 28 /* multiply the local part of V with the local part of x */ 29 #if defined(PETSC_USE_COMPLEX) 30 ierr = MatMultHermitianTranspose(Vloc,Na->xl,Na->work1);CHKERRQ(ierr); 31 #else 32 ierr = MatMultTranspose(Vloc,Na->xl,Na->work1);CHKERRQ(ierr); 33 #endif 34 35 /* form the sum of all the local multiplies: this is work2 = V'*x = 36 sum_{all processors} work1 */ 37 ierr = VecGetArray(Na->work1,&w1);CHKERRQ(ierr); 38 ierr = VecGetArray(Na->work2,&w2);CHKERRQ(ierr); 39 ierr = MPIU_Allreduce(w1,w2,Na->nwork,MPIU_SCALAR,MPIU_SUM,PetscObjectComm((PetscObject)N));CHKERRMPI(ierr); 40 ierr = VecRestoreArray(Na->work1,&w1);CHKERRQ(ierr); 41 ierr = VecRestoreArray(Na->work2,&w2);CHKERRQ(ierr); 42 43 if (Na->c) { /* work2 = C*work2 */ 44 ierr = VecPointwiseMult(Na->work2,Na->c,Na->work2);CHKERRQ(ierr); 45 } 46 47 if (Na->A) { 48 /* form y = A*x */ 49 ierr = MatMult(Na->A,x,y);CHKERRQ(ierr); 50 /* multiply-add y = y + U*work2 */ 51 ierr = MatMultAdd(Uloc,Na->work2,Na->yl,Na->yl);CHKERRQ(ierr); 52 } else { 53 /* multiply y = U*work2 */ 54 ierr = MatMult(Uloc,Na->work2,Na->yl);CHKERRQ(ierr); 55 } 56 57 ierr = VecRestoreArrayRead(x,&a);CHKERRQ(ierr); 58 ierr = VecResetArray(Na->xl);CHKERRQ(ierr); 59 ierr = VecRestoreLocalVector(y,Na->yl);CHKERRQ(ierr); 60 PetscFunctionReturn(0); 61 } 62 63 PetscErrorCode MatDestroy_LRC(Mat N) 64 { 65 Mat_LRC *Na = (Mat_LRC*)N->data; 66 PetscErrorCode ierr; 67 68 PetscFunctionBegin; 69 ierr = MatDestroy(&Na->A);CHKERRQ(ierr); 70 ierr = MatDestroy(&Na->U);CHKERRQ(ierr); 71 ierr = MatDestroy(&Na->V);CHKERRQ(ierr); 72 ierr = VecDestroy(&Na->c);CHKERRQ(ierr); 73 ierr = VecDestroy(&Na->work1);CHKERRQ(ierr); 74 ierr = VecDestroy(&Na->work2);CHKERRQ(ierr); 75 ierr = VecDestroy(&Na->xl);CHKERRQ(ierr); 76 ierr = VecDestroy(&Na->yl);CHKERRQ(ierr); 77 ierr = PetscFree(N->data);CHKERRQ(ierr); 78 ierr = PetscObjectComposeFunction((PetscObject)N,"MatLRCGetMats_C",0);CHKERRQ(ierr); 79 PetscFunctionReturn(0); 80 } 81 82 PetscErrorCode MatLRCGetMats_LRC(Mat N,Mat *A,Mat *U,Vec *c,Mat *V) 83 { 84 Mat_LRC *Na = (Mat_LRC*)N->data; 85 86 PetscFunctionBegin; 87 if (A) *A = Na->A; 88 if (U) *U = Na->U; 89 if (c) *c = Na->c; 90 if (V) *V = Na->V; 91 PetscFunctionReturn(0); 92 } 93 94 /*@ 95 MatLRCGetMats - Returns the constituents of an LRC matrix 96 97 Collective on Mat 98 99 Input Parameter: 100 . N - matrix of type LRC 101 102 Output Parameters: 103 + A - the (sparse) matrix 104 . U - first dense rectangular (tall and skinny) matrix 105 . c - a sequential vector containing the diagonal of C 106 - V - second dense rectangular (tall and skinny) matrix 107 108 Note: 109 The returned matrices need not be destroyed by the caller. 110 111 Level: intermediate 112 113 .seealso: MatCreateLRC() 114 @*/ 115 PetscErrorCode MatLRCGetMats(Mat N,Mat *A,Mat *U,Vec *c,Mat *V) 116 { 117 PetscErrorCode ierr; 118 119 PetscFunctionBegin; 120 ierr = PetscUseMethod(N,"MatLRCGetMats_C",(Mat,Mat*,Mat*,Vec*,Mat*),(N,A,U,c,V));CHKERRQ(ierr); 121 PetscFunctionReturn(0); 122 } 123 124 /*@ 125 MatCreateLRC - Creates a new matrix object that behaves like A + U*C*V' 126 127 Collective on Mat 128 129 Input Parameters: 130 + A - the (sparse) matrix (can be NULL) 131 . U, V - two dense rectangular (tall and skinny) matrices 132 - c - a sequential vector containing the diagonal of C (can be NULL) 133 134 Output Parameter: 135 . N - the matrix that represents A + U*C*V' 136 137 Notes: 138 The matrix A + U*C*V' is not formed! Rather the new matrix 139 object performs the matrix-vector product by first multiplying by 140 A and then adding the other term. 141 142 C is a diagonal matrix (represented as a vector) of order k, 143 where k is the number of columns of both U and V. 144 145 If A is NULL then the new object behaves like a low-rank matrix U*C*V'. 146 147 Use V=U (or V=NULL) for a symmetric low-rank correction, A + U*C*U'. 148 149 If c is NULL then the low-rank correction is just U*V'. 150 151 Level: intermediate 152 153 .seealso: MatLRCGetMats() 154 @*/ 155 PetscErrorCode MatCreateLRC(Mat A,Mat U,Vec c,Mat V,Mat *N) 156 { 157 PetscErrorCode ierr; 158 PetscBool match; 159 PetscInt m,n,k,m1,n1,k1; 160 Mat_LRC *Na; 161 162 PetscFunctionBegin; 163 if (A) PetscValidHeaderSpecific(A,MAT_CLASSID,1); 164 PetscValidHeaderSpecific(U,MAT_CLASSID,2); 165 if (c) PetscValidHeaderSpecific(c,VEC_CLASSID,3); 166 if (V) PetscValidHeaderSpecific(V,MAT_CLASSID,4); 167 else V=U; 168 if (A) PetscCheckSameComm(A,1,U,2); 169 PetscCheckSameComm(U,2,V,4); 170 171 ierr = PetscObjectTypeCompareAny((PetscObject)U,&match,MATSEQDENSE,MATMPIDENSE,"");CHKERRQ(ierr); 172 if (!match) SETERRQ(PetscObjectComm((PetscObject)U),PETSC_ERR_SUP,"Matrix U must be of type dense"); 173 if (V) { 174 ierr = PetscObjectTypeCompareAny((PetscObject)V,&match,MATSEQDENSE,MATMPIDENSE,"");CHKERRQ(ierr); 175 if (!match) SETERRQ(PetscObjectComm((PetscObject)V),PETSC_ERR_SUP,"Matrix V must be of type dense"); 176 } 177 178 ierr = MatGetSize(U,NULL,&k);CHKERRQ(ierr); 179 ierr = MatGetSize(V,NULL,&k1);CHKERRQ(ierr); 180 if (k!=k1) SETERRQ2(PetscObjectComm((PetscObject)U),PETSC_ERR_ARG_INCOMP,"U and V have different number of columns (%D vs %D)",k,k1); 181 ierr = MatGetLocalSize(U,&m,NULL);CHKERRQ(ierr); 182 ierr = MatGetLocalSize(V,&n,NULL);CHKERRQ(ierr); 183 if (A) { 184 ierr = MatGetLocalSize(A,&m1,&n1);CHKERRQ(ierr); 185 if (m!=m1) SETERRQ2(PetscObjectComm((PetscObject)U),PETSC_ERR_ARG_INCOMP,"Local dimensions of U %D and A %D do not match",m,m1); 186 if (n!=n1) SETERRQ2(PetscObjectComm((PetscObject)V),PETSC_ERR_ARG_INCOMP,"Local dimensions of V %D and A %D do not match",n,n1); 187 } 188 if (c) { 189 ierr = VecGetSize(c,&k1);CHKERRQ(ierr); 190 if (k!=k1) SETERRQ2(PetscObjectComm((PetscObject)c),PETSC_ERR_ARG_INCOMP,"The length of c %D does not match the number of columns of U and V (%D)",k1,k); 191 ierr = VecGetLocalSize(c,&k1);CHKERRQ(ierr); 192 if (k!=k1) SETERRQ(PetscObjectComm((PetscObject)c),PETSC_ERR_ARG_INCOMP,"c must be a sequential vector"); 193 } 194 195 ierr = MatCreate(PetscObjectComm((PetscObject)U),N);CHKERRQ(ierr); 196 ierr = MatSetSizes(*N,m,n,PETSC_DECIDE,PETSC_DECIDE);CHKERRQ(ierr); 197 ierr = PetscObjectChangeTypeName((PetscObject)*N,MATLRC);CHKERRQ(ierr); 198 199 ierr = PetscNewLog(*N,&Na);CHKERRQ(ierr); 200 (*N)->data = (void*)Na; 201 Na->A = A; 202 Na->U = U; 203 Na->c = c; 204 Na->V = V; 205 206 if (A) { ierr = PetscObjectReference((PetscObject)A);CHKERRQ(ierr); } 207 ierr = PetscObjectReference((PetscObject)Na->U);CHKERRQ(ierr); 208 ierr = PetscObjectReference((PetscObject)Na->V);CHKERRQ(ierr); 209 if (c) { ierr = PetscObjectReference((PetscObject)c);CHKERRQ(ierr); } 210 211 ierr = VecCreateSeq(PETSC_COMM_SELF,U->cmap->N,&Na->work1);CHKERRQ(ierr); 212 ierr = VecDuplicate(Na->work1,&Na->work2);CHKERRQ(ierr); 213 ierr = PetscMPIIntCast(U->cmap->N,&Na->nwork);CHKERRQ(ierr); 214 215 ierr = VecCreateSeqWithArray(PETSC_COMM_SELF,1,V->rmap->n,NULL,&Na->xl);CHKERRQ(ierr); 216 ierr = VecCreateSeqWithArray(PETSC_COMM_SELF,1,U->rmap->n,NULL,&Na->yl);CHKERRQ(ierr); 217 218 (*N)->ops->destroy = MatDestroy_LRC; 219 (*N)->ops->mult = MatMult_LRC; 220 (*N)->assembled = PETSC_TRUE; 221 (*N)->preallocated = PETSC_TRUE; 222 (*N)->cmap->N = V->rmap->N; 223 (*N)->rmap->N = U->rmap->N; 224 (*N)->cmap->n = V->rmap->n; 225 (*N)->rmap->n = U->rmap->n; 226 227 ierr = PetscObjectComposeFunction((PetscObject)(*N),"MatLRCGetMats_C",MatLRCGetMats_LRC);CHKERRQ(ierr); 228 PetscFunctionReturn(0); 229 } 230