Actual source code: pipefcg.c
1: /*
2: Contributed by Patrick Sanan and Sascha M. Schnepp
3: */
5: #include <../src/ksp/ksp/impls/fcg/pipefcg/pipefcgimpl.h>
7: static PetscBool cited = PETSC_FALSE;
8: static const char citation[] =
9: "@article{SSM2016,\n"
10: " author = {P. Sanan and S.M. Schnepp and D.A. May},\n"
11: " title = {Pipelined, Flexible Krylov Subspace Methods},\n"
12: " journal = {SIAM Journal on Scientific Computing},\n"
13: " volume = {38},\n"
14: " number = {5},\n"
15: " pages = {C441-C470},\n"
16: " year = {2016},\n"
17: " doi = {10.1137/15M1049130},\n"
18: " URL = {http://dx.doi.org/10.1137/15M1049130},\n"
19: " eprint = {http://dx.doi.org/10.1137/15M1049130}\n"
20: "}\n";
22: #define KSPPIPEFCG_DEFAULT_MMAX 15
23: #define KSPPIPEFCG_DEFAULT_NPREALLOC 5
24: #define KSPPIPEFCG_DEFAULT_VECB 5
25: #define KSPPIPEFCG_DEFAULT_TRUNCSTRAT KSP_FCD_TRUNC_TYPE_NOTAY
27: static PetscErrorCode KSPAllocateVectors_PIPEFCG(KSP ksp, PetscInt nvecsneeded, PetscInt chunksize)
28: {
29: PetscErrorCode ierr;
30: PetscInt i;
31: KSP_PIPEFCG *pipefcg;
32: PetscInt nnewvecs, nvecsprev;
35: pipefcg = (KSP_PIPEFCG*)ksp->data;
37: /* Allocate enough new vectors to add chunksize new vectors, reach nvecsneedtotal, or to reach mmax+1, whichever is smallest */
38: if (pipefcg->nvecs < PetscMin(pipefcg->mmax+1,nvecsneeded)){
39: nvecsprev = pipefcg->nvecs;
40: nnewvecs = PetscMin(PetscMax(nvecsneeded-pipefcg->nvecs,chunksize),pipefcg->mmax+1-pipefcg->nvecs);
41: KSPCreateVecs(ksp,nnewvecs,&pipefcg->pQvecs[pipefcg->nchunks],0,NULL);
42: PetscLogObjectParents((PetscObject)ksp,nnewvecs,pipefcg->pQvecs[pipefcg->nchunks]);
43: KSPCreateVecs(ksp,nnewvecs,&pipefcg->pZETAvecs[pipefcg->nchunks],0,NULL);
44: PetscLogObjectParents((PetscObject)ksp,nnewvecs,pipefcg->pZETAvecs[pipefcg->nchunks]);
45: KSPCreateVecs(ksp,nnewvecs,&pipefcg->pPvecs[pipefcg->nchunks],0,NULL);
46: PetscLogObjectParents((PetscObject)ksp,nnewvecs,pipefcg->pPvecs[pipefcg->nchunks]);
47: KSPCreateVecs(ksp,nnewvecs,&pipefcg->pSvecs[pipefcg->nchunks],0,NULL);
48: PetscLogObjectParents((PetscObject)ksp,nnewvecs,pipefcg->pSvecs[pipefcg->nchunks]);
49: pipefcg->nvecs += nnewvecs;
50: for (i=0;i<nnewvecs;++i){
51: pipefcg->Qvecs[nvecsprev + i] = pipefcg->pQvecs[pipefcg->nchunks][i];
52: pipefcg->ZETAvecs[nvecsprev + i] = pipefcg->pZETAvecs[pipefcg->nchunks][i];
53: pipefcg->Pvecs[nvecsprev + i] = pipefcg->pPvecs[pipefcg->nchunks][i];
54: pipefcg->Svecs[nvecsprev + i] = pipefcg->pSvecs[pipefcg->nchunks][i];
55: }
56: pipefcg->chunksizes[pipefcg->nchunks] = nnewvecs;
57: ++pipefcg->nchunks;
58: }
59: return(0);
60: }
62: static PetscErrorCode KSPSetUp_PIPEFCG(KSP ksp)
63: {
65: KSP_PIPEFCG *pipefcg;
66: const PetscInt nworkstd = 5;
69: pipefcg = (KSP_PIPEFCG*)ksp->data;
71: /* Allocate "standard" work vectors (not including the basis and transformed basis vectors) */
72: KSPSetWorkVecs(ksp,nworkstd);
74: /* Allocated space for pointers to additional work vectors
75: note that mmax is the number of previous directions, so we add 1 for the current direction,
76: and an extra 1 for the prealloc (which might be empty) */
77: PetscMalloc4(pipefcg->mmax+1,&(pipefcg->Pvecs),pipefcg->mmax+1,&(pipefcg->pPvecs),pipefcg->mmax+1,&(pipefcg->Svecs),pipefcg->mmax+1,&(pipefcg->pSvecs));
78: PetscMalloc4(pipefcg->mmax+1,&(pipefcg->Qvecs),pipefcg->mmax+1,&(pipefcg->pQvecs),pipefcg->mmax+1,&(pipefcg->ZETAvecs),pipefcg->mmax+1,&(pipefcg->pZETAvecs));
79: PetscMalloc4(pipefcg->mmax+1,&(pipefcg->Pold),pipefcg->mmax+1,&(pipefcg->Sold),pipefcg->mmax+1,&(pipefcg->Qold),pipefcg->mmax+1,&(pipefcg->ZETAold));
80: PetscMalloc1(pipefcg->mmax+1,&(pipefcg->chunksizes));
81: PetscMalloc3(pipefcg->mmax+2,&(pipefcg->dots),pipefcg->mmax+1,&(pipefcg->etas),pipefcg->mmax+2,&(pipefcg->redux));
83: /* If the requested number of preallocated vectors is greater than mmax reduce nprealloc */
84: if (pipefcg->nprealloc > pipefcg->mmax+1){
85: PetscInfo2(NULL,"Requested nprealloc=%d is greater than m_max+1=%d. Resetting nprealloc = m_max+1.\n",pipefcg->nprealloc, pipefcg->mmax+1);
86: }
88: /* Preallocate additional work vectors */
89: KSPAllocateVectors_PIPEFCG(ksp,pipefcg->nprealloc,pipefcg->nprealloc);
91: PetscLogObjectMemory((PetscObject)ksp,(pipefcg->mmax+1)*4*sizeof(Vec*)+(pipefcg->mmax+1)*4*sizeof(Vec**)+(pipefcg->mmax+1)*4*sizeof(Vec*)+
92: (pipefcg->mmax+1)*sizeof(PetscInt)+(pipefcg->mmax+2)*sizeof(Vec*)+(pipefcg->mmax+2)*sizeof(PetscScalar)+(pipefcg->mmax+1)*sizeof(PetscReal));
93: return(0);
94: }
96: static PetscErrorCode KSPSolve_PIPEFCG_cycle(KSP ksp)
97: {
99: PetscInt i,j,k,idx,kdx,mi;
100: KSP_PIPEFCG *pipefcg;
101: PetscScalar alpha=0.0,gamma,*betas,*dots;
102: PetscReal dp=0.0, delta,*eta,*etas;
103: Vec B,R,Z,X,Qcurr,W,ZETAcurr,M,N,Pcurr,Scurr,*redux;
104: Mat Amat,Pmat;
107: /* We have not checked these routines for use with complex numbers. The inner products
108: are likely not defined correctly for that case */
109: if (PetscDefined(USE_COMPLEX) && !PetscDefined(SKIP_COMPLEX)) SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_SUP,"PIPEFGMRES has not been implemented for use with complex scalars");
111: #define VecXDot(x,y,a) (((pipefcg->type) == (KSP_CG_HERMITIAN)) ? VecDot (x,y,a) : VecTDot (x,y,a))
112: #define VecXDotBegin(x,y,a) (((pipefcg->type) == (KSP_CG_HERMITIAN)) ? VecDotBegin (x,y,a) : VecTDotBegin (x,y,a))
113: #define VecXDotEnd(x,y,a) (((pipefcg->type) == (KSP_CG_HERMITIAN)) ? VecDotEnd (x,y,a) : VecTDotEnd (x,y,a))
114: #define VecMXDot(x,n,y,a) (((pipefcg->type) == (KSP_CG_HERMITIAN)) ? VecMDot (x,n,y,a) : VecMTDot (x,n,y,a))
115: #define VecMXDotBegin(x,n,y,a) (((pipefcg->type) == (KSP_CG_HERMITIAN)) ? VecMDotBegin (x,n,y,a) : VecMTDotBegin (x,n,y,a))
116: #define VecMXDotEnd(x,n,y,a) (((pipefcg->type) == (KSP_CG_HERMITIAN)) ? VecMDotEnd (x,n,y,a) : VecMTDotEnd (x,n,y,a))
118: pipefcg = (KSP_PIPEFCG*)ksp->data;
119: X = ksp->vec_sol;
120: B = ksp->vec_rhs;
121: R = ksp->work[0];
122: Z = ksp->work[1];
123: W = ksp->work[2];
124: M = ksp->work[3];
125: N = ksp->work[4];
127: redux = pipefcg->redux;
128: dots = pipefcg->dots;
129: etas = pipefcg->etas;
130: betas = dots; /* dots takes the result of all dot products of which the betas are a subset */
132: PCGetOperators(ksp->pc,&Amat,&Pmat);
134: /* Compute cycle initial residual */
135: KSP_MatMult(ksp,Amat,X,R);
136: VecAYPX(R,-1.0,B); /* r <- b - Ax */
137: KSP_PCApply(ksp,R,Z); /* z <- Br */
139: Pcurr = pipefcg->Pvecs[0];
140: Scurr = pipefcg->Svecs[0];
141: Qcurr = pipefcg->Qvecs[0];
142: ZETAcurr = pipefcg->ZETAvecs[0];
143: VecCopy(Z,Pcurr);
144: KSP_MatMult(ksp,Amat,Pcurr,Scurr); /* S = Ap */
145: VecCopy(Scurr,W); /* w = s = Az */
147: /* Initial state of pipelining intermediates */
148: redux[0] = R;
149: redux[1] = W;
150: VecMXDotBegin(Z,2,redux,dots);
151: PetscCommSplitReductionBegin(PetscObjectComm((PetscObject)Z)); /* perform asynchronous reduction */
152: KSP_PCApply(ksp,W,M); /* m = B(w) */
153: KSP_MatMult(ksp,Amat,M,N); /* n = Am */
154: VecCopy(M,Qcurr); /* q = m */
155: VecCopy(N,ZETAcurr); /* zeta = n */
156: VecMXDotEnd(Z,2,redux,dots);
157: gamma = dots[0];
158: delta = PetscRealPart(dots[1]);
159: etas[0] = delta;
160: alpha = gamma/delta;
162: i = 0;
163: do {
164: ksp->its++;
166: /* Update X, R, Z, W */
167: VecAXPY(X,+alpha,Pcurr); /* x <- x + alpha * pi */
168: VecAXPY(R,-alpha,Scurr); /* r <- r - alpha * si */
169: VecAXPY(Z,-alpha,Qcurr); /* z <- z - alpha * qi */
170: VecAXPY(W,-alpha,ZETAcurr); /* w <- w - alpha * zetai */
172: /* Compute norm for convergence check */
173: switch (ksp->normtype) {
174: case KSP_NORM_PRECONDITIONED:
175: VecNorm(Z,NORM_2,&dp); /* dp <- sqrt(z'*z) = sqrt(e'*A'*B'*B*A*e) */
176: break;
177: case KSP_NORM_UNPRECONDITIONED:
178: VecNorm(R,NORM_2,&dp); /* dp <- sqrt(r'*r) = sqrt(e'*A'*A*e) */
179: break;
180: case KSP_NORM_NATURAL:
181: dp = PetscSqrtReal(PetscAbsScalar(gamma)); /* dp <- sqrt(r'*z) = sqrt(e'*A'*B*A*e) */
182: break;
183: case KSP_NORM_NONE:
184: dp = 0.0;
185: break;
186: default: SETERRQ1(PetscObjectComm((PetscObject)ksp),PETSC_ERR_SUP,"%s",KSPNormTypes[ksp->normtype]);
187: }
189: /* Check for convergence */
190: ksp->rnorm = dp;
191: KSPLogResidualHistory(ksp,dp);
192: KSPMonitor(ksp,ksp->its,dp);
193: (*ksp->converged)(ksp,ksp->its,dp,&ksp->reason,ksp->cnvP);
194: if (ksp->reason) return(0);
196: /* Computations of current iteration done */
197: ++i;
199: /* If needbe, allocate a new chunk of vectors in P and C */
200: KSPAllocateVectors_PIPEFCG(ksp,i+1,pipefcg->vecb);
202: /* Note that we wrap around and start clobbering old vectors */
203: idx = i % (pipefcg->mmax+1);
204: Pcurr = pipefcg->Pvecs[idx];
205: Scurr = pipefcg->Svecs[idx];
206: Qcurr = pipefcg->Qvecs[idx];
207: ZETAcurr = pipefcg->ZETAvecs[idx];
208: eta = pipefcg->etas+idx;
210: /* number of old directions to orthogonalize against */
211: switch(pipefcg->truncstrat){
212: case KSP_FCD_TRUNC_TYPE_STANDARD:
213: mi = pipefcg->mmax;
214: break;
215: case KSP_FCD_TRUNC_TYPE_NOTAY:
216: mi = ((i-1) % pipefcg->mmax)+1;
217: break;
218: default:
219: SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"Unrecognized Truncation Strategy");
220: }
222: /* Pick old p,s,q,zeta in a way suitable for VecMDot */
223: VecCopy(Z,Pcurr);
224: for (k=PetscMax(0,i-mi),j=0;k<i;++j,++k){
225: kdx = k % (pipefcg->mmax+1);
226: pipefcg->Pold[j] = pipefcg->Pvecs[kdx];
227: pipefcg->Sold[j] = pipefcg->Svecs[kdx];
228: pipefcg->Qold[j] = pipefcg->Qvecs[kdx];
229: pipefcg->ZETAold[j] = pipefcg->ZETAvecs[kdx];
230: redux[j] = pipefcg->Svecs[kdx];
231: }
232: redux[j] = R; /* If the above loop is not executed redux contains only R => all beta_k = 0, only gamma, delta != 0 */
233: redux[j+1] = W;
235: VecMXDotBegin(Z,j+2,redux,betas); /* Start split reductions for beta_k = (z,s_k), gamma = (z,r), delta = (z,w) */
236: PetscCommSplitReductionBegin(PetscObjectComm((PetscObject)Z)); /* perform asynchronous reduction */
237: VecWAXPY(N,-1.0,R,W); /* m = u + B(w-r): (a) ntmp = w-r */
238: KSP_PCApply(ksp,N,M); /* m = u + B(w-r): (b) mtmp = B(ntmp) = B(w-r) */
239: VecAXPY(M,1.0,Z); /* m = u + B(w-r): (c) m = z + mtmp */
240: KSP_MatMult(ksp,Amat,M,N); /* n = Am */
241: VecMXDotEnd(Z,j+2,redux,betas); /* Finish split reductions */
242: gamma = betas[j];
243: delta = PetscRealPart(betas[j+1]);
245: *eta = 0.;
246: for (k=PetscMax(0,i-mi),j=0;k<i;++j,++k){
247: kdx = k % (pipefcg->mmax+1);
248: betas[j] /= -etas[kdx]; /* betak /= etak */
249: *eta -= ((PetscReal)(PetscAbsScalar(betas[j])*PetscAbsScalar(betas[j]))) * etas[kdx];
250: /* etaitmp = -betaik^2 * etak */
251: }
252: *eta += delta; /* etai = delta -betaik^2 * etak */
253: if (*eta < 0.) {
254: pipefcg->norm_breakdown = PETSC_TRUE;
255: PetscInfo1(ksp,"Restart due to square root breakdown at it = \n",ksp->its);
256: break;
257: } else {
258: alpha= gamma/(*eta); /* alpha = gamma/etai */
259: }
261: /* project out stored search directions using classical G-S */
262: VecCopy(Z,Pcurr);
263: VecCopy(W,Scurr);
264: VecCopy(M,Qcurr);
265: VecCopy(N,ZETAcurr);
266: VecMAXPY(Pcurr ,j,betas,pipefcg->Pold); /* pi <- ui - sum_k beta_k p_k */
267: VecMAXPY(Scurr ,j,betas,pipefcg->Sold); /* si <- wi - sum_k beta_k s_k */
268: VecMAXPY(Qcurr ,j,betas,pipefcg->Qold); /* qi <- m - sum_k beta_k q_k */
269: VecMAXPY(ZETAcurr,j,betas,pipefcg->ZETAold); /* zetai <- n - sum_k beta_k zeta_k */
271: } while (ksp->its < ksp->max_it);
272: if (i >= ksp->max_it) ksp->reason = KSP_DIVERGED_ITS;
273: return(0);
274: }
276: static PetscErrorCode KSPSolve_PIPEFCG(KSP ksp)
277: {
279: KSP_PIPEFCG *pipefcg;
280: PetscScalar gamma;
281: PetscReal dp=0.0;
282: Vec B,R,Z,X;
283: Mat Amat,Pmat;
285: #define VecXDot(x,y,a) (((pipefcg->type) == (KSP_CG_HERMITIAN)) ? VecDot (x,y,a) : VecTDot (x,y,a))
288: PetscCitationsRegister(citation,&cited);
290: pipefcg = (KSP_PIPEFCG*)ksp->data;
291: X = ksp->vec_sol;
292: B = ksp->vec_rhs;
293: R = ksp->work[0];
294: Z = ksp->work[1];
296: PCGetOperators(ksp->pc,&Amat,&Pmat);
298: /* Compute initial residual needed for convergence check*/
299: ksp->its = 0;
300: if (!ksp->guess_zero) {
301: KSP_MatMult(ksp,Amat,X,R);
302: VecAYPX(R,-1.0,B); /* r <- b - Ax */
303: } else {
304: VecCopy(B,R); /* r <- b (x is 0) */
305: }
306: switch (ksp->normtype) {
307: case KSP_NORM_PRECONDITIONED:
308: KSP_PCApply(ksp,R,Z); /* z <- Br */
309: VecNorm(Z,NORM_2,&dp); /* dp <- dqrt(z'*z) = sqrt(e'*A'*B'*B*A*e) */
310: break;
311: case KSP_NORM_UNPRECONDITIONED:
312: VecNorm(R,NORM_2,&dp); /* dp <- sqrt(r'*r) = sqrt(e'*A'*A*e) */
313: break;
314: case KSP_NORM_NATURAL:
315: KSP_PCApply(ksp,R,Z); /* z <- Br */
316: VecXDot(Z,R,&gamma);
317: dp = PetscSqrtReal(PetscAbsScalar(gamma)); /* dp <- sqrt(r'*z) = sqrt(e'*A'*B*A*e) */
318: break;
319: case KSP_NORM_NONE:
320: dp = 0.0;
321: break;
322: default: SETERRQ1(PetscObjectComm((PetscObject)ksp),PETSC_ERR_SUP,"%s",KSPNormTypes[ksp->normtype]);
323: }
325: /* Initial Convergence Check */
326: KSPLogResidualHistory(ksp,dp);
327: KSPMonitor(ksp,0,dp);
328: ksp->rnorm = dp;
329: (*ksp->converged)(ksp,0,dp,&ksp->reason,ksp->cnvP);
330: if (ksp->reason) return(0);
332: do {
333: /* A cycle is broken only if a norm breakdown occurs. If not the entire solve happens in a single cycle.
334: This is coded this way to allow both truncation and truncation-restart strategy
335: (see KSPFCDGetNumOldDirections()) */
336: KSPSolve_PIPEFCG_cycle(ksp);
337: if (ksp->reason) return(0);
338: if (pipefcg->norm_breakdown) {
339: pipefcg->n_restarts++;
340: pipefcg->norm_breakdown = PETSC_FALSE;
341: }
342: } while (ksp->its < ksp->max_it);
344: if (ksp->its >= ksp->max_it) ksp->reason = KSP_DIVERGED_ITS;
345: return(0);
346: }
348: static PetscErrorCode KSPDestroy_PIPEFCG(KSP ksp)
349: {
351: PetscInt i;
352: KSP_PIPEFCG *pipefcg;
355: pipefcg = (KSP_PIPEFCG*)ksp->data;
357: /* Destroy "standard" work vecs */
358: VecDestroyVecs(ksp->nwork,&ksp->work);
360: /* Destroy vectors of old directions and the arrays that manage pointers to them */
361: if (pipefcg->nvecs){
362: for (i=0;i<pipefcg->nchunks;++i){
363: VecDestroyVecs(pipefcg->chunksizes[i],&pipefcg->pPvecs[i]);
364: VecDestroyVecs(pipefcg->chunksizes[i],&pipefcg->pSvecs[i]);
365: VecDestroyVecs(pipefcg->chunksizes[i],&pipefcg->pQvecs[i]);
366: VecDestroyVecs(pipefcg->chunksizes[i],&pipefcg->pZETAvecs[i]);
367: }
368: }
369: PetscFree4(pipefcg->Pvecs,pipefcg->Svecs,pipefcg->pPvecs,pipefcg->pSvecs);
370: PetscFree4(pipefcg->Qvecs,pipefcg->ZETAvecs,pipefcg->pQvecs,pipefcg->pZETAvecs);
371: PetscFree4(pipefcg->Pold,pipefcg->Sold,pipefcg->Qold,pipefcg->ZETAold);
372: PetscFree(pipefcg->chunksizes);
373: PetscFree3(pipefcg->dots,pipefcg->etas,pipefcg->redux);
374: KSPDestroyDefault(ksp);
375: return(0);
376: }
378: static PetscErrorCode KSPView_PIPEFCG(KSP ksp,PetscViewer viewer)
379: {
380: KSP_PIPEFCG *pipefcg = (KSP_PIPEFCG*)ksp->data;
382: PetscBool iascii,isstring;
383: const char *truncstr;
386: PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);
387: PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERSTRING,&isstring);
389: if (pipefcg->truncstrat == KSP_FCD_TRUNC_TYPE_STANDARD){
390: truncstr = "Using standard truncation strategy";
391: } else if (pipefcg->truncstrat == KSP_FCD_TRUNC_TYPE_NOTAY){
392: truncstr = "Using Notay's truncation strategy";
393: } else {
394: SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"Undefined FCD truncation strategy");
395: }
397: if (iascii) {
398: PetscViewerASCIIPrintf(viewer," max previous directions = %D\n",pipefcg->mmax);
399: PetscViewerASCIIPrintf(viewer," preallocated %D directions\n",PetscMin(pipefcg->nprealloc,pipefcg->mmax+1));
400: PetscViewerASCIIPrintf(viewer," %s\n",truncstr);
401: PetscViewerASCIIPrintf(viewer," restarts performed = %D \n", pipefcg->n_restarts);
402: } else if (isstring) {
403: PetscViewerStringSPrintf(viewer,
404: "max previous directions = %D, preallocated %D directions, %s truncation strategy",
405: pipefcg->mmax,pipefcg->nprealloc,truncstr);
406: }
407: return(0);
408: }
410: /*@
411: KSPPIPEFCGSetMmax - set the maximum number of previous directions PIPEFCG will store for orthogonalization
413: Note: mmax + 1 directions are stored (mmax previous ones along with the current one)
414: and whether all are used in each iteration also depends on the truncation strategy
415: (see KSPPIPEFCGSetTruncationType)
417: Logically Collective on ksp
419: Input Parameters:
420: + ksp - the Krylov space context
421: - mmax - the maximum number of previous directions to orthogonalize against
423: Level: intermediate
425: Options Database:
426: . -ksp_pipefcg_mmax <N>
428: .seealso: KSPPIPEFCG, KSPPIPEFCGSetTruncationType(), KSPPIPEFCGSetNprealloc()
429: @*/
430: PetscErrorCode KSPPIPEFCGSetMmax(KSP ksp,PetscInt mmax)
431: {
432: KSP_PIPEFCG *pipefcg=(KSP_PIPEFCG*)ksp->data;
437: pipefcg->mmax=mmax;
438: return(0);
439: }
441: /*@
442: KSPPIPEFCGGetMmax - get the maximum number of previous directions PIPEFCG will store
444: Note: PIPEFCG stores mmax+1 directions at most (mmax previous ones, and the current one)
446: Not Collective
448: Input Parameter:
449: . ksp - the Krylov space context
451: Output Parameter:
452: . mmax - the maximum number of previous directons allowed for orthogonalization
454: Options Database:
455: . -ksp_pipefcg_mmax <N>
457: Level: intermediate
459: .seealso: KSPPIPEFCG, KSPPIPEFCGGetTruncationType(), KSPPIPEFCGGetNprealloc(), KSPPIPEFCGSetMmax()
460: @*/
461: PetscErrorCode KSPPIPEFCGGetMmax(KSP ksp,PetscInt *mmax)
462: {
463: KSP_PIPEFCG *pipefcg=(KSP_PIPEFCG*)ksp->data;
467: *mmax=pipefcg->mmax;
468: return(0);
469: }
471: /*@
472: KSPPIPEFCGSetNprealloc - set the number of directions to preallocate with PIPEFCG
474: Logically Collective on ksp
476: Input Parameters:
477: + ksp - the Krylov space context
478: - nprealloc - the number of vectors to preallocate
480: Level: advanced
482: Options Database:
483: . -ksp_pipefcg_nprealloc <N>
485: .seealso: KSPPIPEFCG, KSPPIPEFCGSetTruncationType(), KSPPIPEFCGGetNprealloc()
486: @*/
487: PetscErrorCode KSPPIPEFCGSetNprealloc(KSP ksp,PetscInt nprealloc)
488: {
489: KSP_PIPEFCG *pipefcg=(KSP_PIPEFCG*)ksp->data;
494: pipefcg->nprealloc = nprealloc;
495: return(0);
496: }
498: /*@
499: KSPPIPEFCGGetNprealloc - get the number of directions to preallocate by PIPEFCG
501: Not Collective
503: Input Parameter:
504: . ksp - the Krylov space context
506: Output Parameter:
507: . nprealloc - the number of directions preallocated
509: Options Database:
510: . -ksp_pipefcg_nprealloc <N>
512: Level: advanced
514: .seealso: KSPPIPEFCG, KSPPIPEFCGGetTruncationType(), KSPPIPEFCGSetNprealloc()
515: @*/
516: PetscErrorCode KSPPIPEFCGGetNprealloc(KSP ksp,PetscInt *nprealloc)
517: {
518: KSP_PIPEFCG *pipefcg=(KSP_PIPEFCG*)ksp->data;
522: *nprealloc = pipefcg->nprealloc;
523: return(0);
524: }
526: /*@
527: KSPPIPEFCGSetTruncationType - specify how many of its stored previous directions PIPEFCG uses during orthoganalization
529: Logically Collective on ksp
531: KSP_FCD_TRUNC_TYPE_STANDARD uses all (up to mmax) stored directions
532: KSP_FCD_TRUNC_TYPE_NOTAY uses max(1,mod(i,mmax)) stored directions at iteration i=0,1,..
534: Input Parameters:
535: + ksp - the Krylov space context
536: - truncstrat - the choice of strategy
538: Level: intermediate
540: Options Database:
541: . -ksp_pipefcg_truncation_type <standard,notay> - which stored search directions to orthogonalize against
543: .seealso: KSPPIPEFCG, KSPPIPEFCGGetTruncationType, KSPFCDTruncationType
544: @*/
545: PetscErrorCode KSPPIPEFCGSetTruncationType(KSP ksp,KSPFCDTruncationType truncstrat)
546: {
547: KSP_PIPEFCG *pipefcg=(KSP_PIPEFCG*)ksp->data;
552: pipefcg->truncstrat=truncstrat;
553: return(0);
554: }
556: /*@
557: KSPPIPEFCGGetTruncationType - get the truncation strategy employed by PIPEFCG
559: Not Collective
561: Input Parameter:
562: . ksp - the Krylov space context
564: Output Parameter:
565: . truncstrat - the strategy type
567: Options Database:
568: . -ksp_pipefcg_truncation_type <standard,notay> - which stored basis vectors to orthogonalize against
570: Level: intermediate
572: .seealso: KSPPIPEFCG, KSPPIPEFCGSetTruncationType, KSPFCDTruncationType
573: @*/
574: PetscErrorCode KSPPIPEFCGGetTruncationType(KSP ksp,KSPFCDTruncationType *truncstrat)
575: {
576: KSP_PIPEFCG *pipefcg=(KSP_PIPEFCG*)ksp->data;
580: *truncstrat=pipefcg->truncstrat;
581: return(0);
582: }
584: static PetscErrorCode KSPSetFromOptions_PIPEFCG(PetscOptionItems *PetscOptionsObject,KSP ksp)
585: {
587: KSP_PIPEFCG *pipefcg=(KSP_PIPEFCG*)ksp->data;
588: PetscInt mmax,nprealloc;
589: PetscBool flg;
592: PetscOptionsHead(PetscOptionsObject,"KSP PIPEFCG options");
593: PetscOptionsInt("-ksp_pipefcg_mmax","Number of search directions to storue","KSPPIPEFCGSetMmax",pipefcg->mmax,&mmax,&flg);
594: if (flg) KSPPIPEFCGSetMmax(ksp,mmax);
595: PetscOptionsInt("-ksp_pipefcg_nprealloc","Number of directions to preallocate","KSPPIPEFCGSetNprealloc",pipefcg->nprealloc,&nprealloc,&flg);
596: if (flg) { KSPPIPEFCGSetNprealloc(ksp,nprealloc); }
597: PetscOptionsEnum("-ksp_pipefcg_truncation_type","Truncation approach for directions","KSPFCGSetTruncationType",KSPFCDTruncationTypes,(PetscEnum)pipefcg->truncstrat,(PetscEnum*)&pipefcg->truncstrat,NULL);
598: PetscOptionsTail();
599: return(0);
600: }
602: /*MC
604: KSPPIPEFCG - Implements a Pipelined, Flexible Conjugate Gradient method.
606: Options Database Keys:
607: + -ksp_pipefcg_mmax <N> - The number of previous search directions to store
608: . -ksp_pipefcg_nprealloc <N> - The number of previous search directions to preallocate
609: - -ksp_pipefcg_truncation_type <standard,notay> - which stored search directions to orthogonalize against
611: Notes:
612: Supports left preconditioning only.
614: The natural "norm" for this method is (u,Au), where u is the preconditioned residual. As with standard CG, this norm is available at no additional computational cost. Choosing preconditioned or unpreconditioned norms involve an extra blocking global reduction, thus removing any benefit from pipelining.
616: MPI configuration may be necessary for reductions to make asynchronous progress, which is important for performance of pipelined methods.
617: See the FAQ on the PETSc website for details.
619: Reference:
620: P. Sanan, S.M. Schnepp, and D.A. May,
621: "Pipelined, Flexible Krylov Subspace Methods,"
622: SIAM Journal on Scientific Computing 2016 38:5, C441-C470,
623: DOI: 10.1137/15M1049130
625: Level: intermediate
627: .seealso: KSPFCG, KSPPIPECG, KSPPIPECR, KSPGCR, KSPPIPEGCR, KSPFGMRES, KSPCG, KSPPIPEFCGSetMmax(), KSPPIPEFCGGetMmax(), KSPPIPEFCGSetNprealloc(), KSPPIPEFCGGetNprealloc(), KSPPIPEFCGSetTruncationType(), KSPPIPEFCGGetTruncationType()
629: M*/
630: PETSC_EXTERN PetscErrorCode KSPCreate_PIPEFCG(KSP ksp)
631: {
633: KSP_PIPEFCG *pipefcg;
636: PetscNewLog(ksp,&pipefcg);
637: #if !defined(PETSC_USE_COMPLEX)
638: pipefcg->type = KSP_CG_SYMMETRIC;
639: #else
640: pipefcg->type = KSP_CG_HERMITIAN;
641: #endif
642: pipefcg->mmax = KSPPIPEFCG_DEFAULT_MMAX;
643: pipefcg->nprealloc = KSPPIPEFCG_DEFAULT_NPREALLOC;
644: pipefcg->nvecs = 0;
645: pipefcg->vecb = KSPPIPEFCG_DEFAULT_VECB;
646: pipefcg->nchunks = 0;
647: pipefcg->truncstrat = KSPPIPEFCG_DEFAULT_TRUNCSTRAT;
648: pipefcg->n_restarts = 0;
650: ksp->data = (void*)pipefcg;
652: KSPSetSupportedNorm(ksp,KSP_NORM_PRECONDITIONED,PC_LEFT,2);
653: KSPSetSupportedNorm(ksp,KSP_NORM_NATURAL,PC_LEFT,1);
654: KSPSetSupportedNorm(ksp,KSP_NORM_UNPRECONDITIONED,PC_LEFT,1);
655: KSPSetSupportedNorm(ksp,KSP_NORM_NONE,PC_LEFT,1);
657: ksp->ops->setup = KSPSetUp_PIPEFCG;
658: ksp->ops->solve = KSPSolve_PIPEFCG;
659: ksp->ops->destroy = KSPDestroy_PIPEFCG;
660: ksp->ops->view = KSPView_PIPEFCG;
661: ksp->ops->setfromoptions = KSPSetFromOptions_PIPEFCG;
662: ksp->ops->buildsolution = KSPBuildSolutionDefault;
663: ksp->ops->buildresidual = KSPBuildResidualDefault;
664: return(0);
665: }