Date: 2026-05-01T10:02:09+00:00

Actual source code: svdmon.c

      1: /*
      2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
      4:    Copyright (c) 2002-, Universitat Politecnica de Valencia, Spain

      6:    This file is part of SLEPc.
      7:    SLEPc is distributed under a 2-clause BSD license (see LICENSE).
      8:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      9: */
     10: /*
     11:    SVD routines related to monitors
     12: */

     14: #include <slepc/private/svdimpl.h>
     15: #include <petscdraw.h>

     17: /*
     18:    Runs the user provided monitor routines, if any.
     19: */
     20: PetscErrorCode SVDMonitor(SVD svd,PetscInt it,PetscInt nconv,PetscReal *sigma,PetscReal *errest,PetscInt nest)
     21: {
     22:   PetscInt       i,n = svd->numbermonitors;

     24:   PetscFunctionBegin;
     25:   for (i=0;i<n;i++) PetscCall((*svd->monitor[i])(svd,it,nconv,sigma,errest,nest,svd->monitorcontext[i]));
     26:   PetscFunctionReturn(PETSC_SUCCESS);
     27: }

     29: /*@C
     30:    SVDMonitorSet - Sets an ADDITIONAL function to be called at every
     31:    iteration to monitor the error estimates for each requested singular triplet.

     33:    Logically Collective

     35:    Input Parameters:
     36: +  svd            - the singular value solver context
     37: .  monitor        - pointer to function (if this is `NULL`, it turns off monitoring),
     38:                     see `SVDMonitorFn`
     39: .  ctx            - [optional] context for private data for the monitor routine
     40:                     (use `NULL` if no context is desired)
     41: -  monitordestroy - [optional] routine that frees monitor context (may be `NULL`),
     42:                     see `PetscCtxDestroyFn` for the calling sequence

     44:    Options Database Keys:
     45: +  -svd_monitor                    - print only the first error estimate
     46: .  -svd_monitor_all                - print error estimates at each iteration
     47: .  -svd_monitor_conv               - print the singular value approximations only when
     48:                                      convergence has been reached
     49: .  -svd_monitor_conditioning       - print the condition number when available
     50: .  -svd_monitor draw::draw_lg      - sets line graph monitor for the first unconverged
     51:                                      approximate singular value
     52: .  -svd_monitor_all draw::draw_lg  - sets line graph monitor for all unconverged
     53:                                      approximate singular values
     54: .  -svd_monitor_conv draw::draw_lg - sets line graph monitor for convergence history
     55: -  -svd_monitor_cancel             - cancels all monitors that have been hardwired into
     56:                                      a code by calls to `SVDMonitorSet()`, but does not cancel
     57:                                      those set via the options database.

     59:    Notes:
     60:    The options database option `-svd_monitor` and related options are the easiest way
     61:    to turn on `SVD` iteration monitoring.

     63:    `SVDMonitorRegister()` provides a way to associate an options database key with `SVD`
     64:    monitor function.

     66:    Several different monitoring routines may be set by calling `SVDMonitorSet()` multiple
     67:    times; all will be called in the order in which they were set.

     69:    Fortran Note:
     70:    Only a single monitor function can be set for each `SVD` object.

     72:    Level: intermediate

     74: .seealso: [](ch:svd), `SVDMonitorFirst()`, `SVDMonitorAll()`, `SVDMonitorConverged()`, `SVDMonitorConditioning()`, `SVDMonitorFirstDrawLG()`, `SVDMonitorAllDrawLG()`, `SVDMonitorConvergedDrawLG()`, `SVDMonitorCancel()`
     75: @*/
     76: PetscErrorCode SVDMonitorSet(SVD svd,SVDMonitorFn *monitor,PetscCtx ctx,PetscCtxDestroyFn *monitordestroy)
     77: {
     78:   PetscInt  i;
     79:   PetscBool identical;

     81:   PetscFunctionBegin;
     83:   for (i=0;i<svd->numbermonitors;i++) {
     84:     PetscCall(PetscMonitorCompare((PetscErrorCode(*)(void))(PetscVoidFn*)monitor,ctx,monitordestroy,(PetscErrorCode (*)(void))(PetscVoidFn*)svd->monitor[i],svd->monitorcontext[i],svd->monitordestroy[i],&identical));
     85:     if (identical) PetscFunctionReturn(PETSC_SUCCESS);
     86:   }
     87:   PetscCheck(svd->numbermonitors<MAXSVDMONITORS,PetscObjectComm((PetscObject)svd),PETSC_ERR_ARG_OUTOFRANGE,"Too many SVD monitors set");
     88:   svd->monitor[svd->numbermonitors]           = monitor;
     89:   svd->monitorcontext[svd->numbermonitors]    = ctx;
     90:   svd->monitordestroy[svd->numbermonitors++]  = monitordestroy;
     91:   PetscFunctionReturn(PETSC_SUCCESS);
     92: }

     94: /*@
     95:    SVDMonitorCancel - Clears all monitors for an `SVD` object.

     97:    Logically Collective

     99:    Input Parameter:
    100: .  svd - the singular value solver context

    102:    Options Database Key:
    103: .  -svd_monitor_cancel - cancels all monitors that have been hardwired into a code by calls to
    104:                          `SVDMonitorSet()`, but does not cancel those set via the options database.

    106:    Level: intermediate

    108: .seealso: [](ch:svd), `SVDMonitorSet()`
    109: @*/
    110: PetscErrorCode SVDMonitorCancel(SVD svd)
    111: {
    112:   PetscInt       i;

    114:   PetscFunctionBegin;
    116:   for (i=0; i<svd->numbermonitors; i++) {
    117:     if (svd->monitordestroy[i]) PetscCall((*svd->monitordestroy[i])(&svd->monitorcontext[i]));
    118:   }
    119:   svd->numbermonitors = 0;
    120:   PetscFunctionReturn(PETSC_SUCCESS);
    121: }

    123: /*@C
    124:    SVDGetMonitorContext - Gets the monitor context, as set by
    125:    `SVDMonitorSet()` for the FIRST monitor only.

    127:    Not Collective

    129:    Input Parameter:
    130: .  svd - the singular value solver context

    132:    Output Parameter:
    133: .  ctx - monitor context

    135:    Level: intermediate

    137: .seealso: [](ch:svd), `SVDMonitorSet()`
    138: @*/
    139: PetscErrorCode SVDGetMonitorContext(SVD svd,PetscCtxRt ctx)
    140: {
    141:   PetscFunctionBegin;
    143:   *(void**)ctx = svd->monitorcontext[0];
    144:   PetscFunctionReturn(PETSC_SUCCESS);
    145: }

    147: /*@C
    148:    SVDMonitorFirst - Print the first unconverged approximate value and
    149:    error estimate at each iteration of the singular value solver.

    151:    Collective

    153:    Input Parameters:
    154: +  svd    - the singular value solver context
    155: .  its    - iteration number
    156: .  nconv  - number of converged singular triplets so far
    157: .  sigma  - singular values
    158: .  errest - error estimates
    159: .  nest   - number of error estimates to display
    160: -  vf     - viewer and format for monitoring

    162:    Options Database Key:
    163: .  -svd_monitor - activates `SVDMonitorFirst()`

    165:    Note:
    166:    This is not called directly by users, rather one calls `SVDMonitorSet()`, with this
    167:    function as an argument, to cause the monitor to be used during the `SVD` solve.

    169:    Level: intermediate

    171: .seealso: [](ch:svd), `SVDMonitorSet()`, `SVDMonitorAll()`, `SVDMonitorConditioning()`, `SVDMonitorConverged()`
    172: @*/
    173: PetscErrorCode SVDMonitorFirst(SVD svd,PetscInt its,PetscInt nconv,PetscReal sigma[],PetscReal errest[],PetscInt nest,PetscViewerAndFormat *vf)
    174: {
    175:   PetscViewer    viewer = vf->viewer;

    177:   PetscFunctionBegin;
    180:   if (its==1 && ((PetscObject)svd)->prefix) PetscCall(PetscViewerASCIIPrintf(viewer,"  Singular value approximations and residual norms for %s solve.\n",((PetscObject)svd)->prefix));
    181:   if (nconv<nest) {
    182:     PetscCall(PetscViewerPushFormat(viewer,vf->format));
    183:     PetscCall(PetscViewerASCIIAddTab(viewer,((PetscObject)svd)->tablevel));
    184:     PetscCall(PetscViewerASCIIPrintf(viewer,"%3" PetscInt_FMT " SVD nconv=%" PetscInt_FMT " first unconverged value (error)",its,nconv));
    185:     PetscCall(PetscViewerASCIIUseTabs(viewer,PETSC_FALSE));
    186:     PetscCall(PetscViewerASCIIPrintf(viewer," %g (%10.8e)\n",(double)sigma[nconv],(double)errest[nconv]));
    187:     PetscCall(PetscViewerASCIIUseTabs(viewer,PETSC_TRUE));
    188:     PetscCall(PetscViewerASCIISubtractTab(viewer,((PetscObject)svd)->tablevel));
    189:     PetscCall(PetscViewerPopFormat(viewer));
    190:   }
    191:   PetscFunctionReturn(PETSC_SUCCESS);
    192: }

    194: /*@C
    195:    SVDMonitorAll - Print the current approximate values and
    196:    error estimates at each iteration of the singular value solver.

    198:    Collective

    200:    Input Parameters:
    201: +  svd    - the singular value solver context
    202: .  its    - iteration number
    203: .  nconv  - number of converged singular triplets so far
    204: .  sigma  - singular values
    205: .  errest - error estimates
    206: .  nest   - number of error estimates to display
    207: -  vf     - viewer and format for monitoring

    209:    Options Database Key:
    210: .  -svd_monitor_all - activates `SVDMonitorAll()`

    212:    Note:
    213:    This is not called directly by users, rather one calls `SVDMonitorSet()`, with this
    214:    function as an argument, to cause the monitor to be used during the `SVD` solve.

    216:    Level: intermediate

    218: .seealso: [](ch:svd), `SVDMonitorSet()`, `SVDMonitorFirst()`, `SVDMonitorConditioning()`, `SVDMonitorConverged()`
    219: @*/
    220: PetscErrorCode SVDMonitorAll(SVD svd,PetscInt its,PetscInt nconv,PetscReal sigma[],PetscReal errest[],PetscInt nest,PetscViewerAndFormat *vf)
    221: {
    222:   PetscInt       i;
    223:   PetscViewer    viewer = vf->viewer;

    225:   PetscFunctionBegin;
    228:   PetscCall(PetscViewerPushFormat(viewer,vf->format));
    229:   PetscCall(PetscViewerASCIIAddTab(viewer,((PetscObject)svd)->tablevel));
    230:   if (its==1 && ((PetscObject)svd)->prefix) PetscCall(PetscViewerASCIIPrintf(viewer,"  Singular value approximations and residual norms for %s solve.\n",((PetscObject)svd)->prefix));
    231:   PetscCall(PetscViewerASCIIPrintf(viewer,"%3" PetscInt_FMT " SVD nconv=%" PetscInt_FMT " Values (Errors)",its,nconv));
    232:   PetscCall(PetscViewerASCIIUseTabs(viewer,PETSC_FALSE));
    233:   for (i=0;i<nest;i++) PetscCall(PetscViewerASCIIPrintf(viewer," %g (%10.8e)",(double)sigma[i],(double)errest[i]));
    234:   PetscCall(PetscViewerASCIIPrintf(viewer,"\n"));
    235:   PetscCall(PetscViewerASCIIUseTabs(viewer,PETSC_TRUE));
    236:   PetscCall(PetscViewerASCIISubtractTab(viewer,((PetscObject)svd)->tablevel));
    237:   PetscCall(PetscViewerPopFormat(viewer));
    238:   PetscFunctionReturn(PETSC_SUCCESS);
    239: }

    241: /*@C
    242:    SVDMonitorConverged - Print the approximate values and
    243:    error estimates as they converge.

    245:    Collective

    247:    Input Parameters:
    248: +  svd    - the singular value solver context
    249: .  its    - iteration number
    250: .  nconv  - number of converged singular triplets so far
    251: .  sigma  - singular values
    252: .  errest - error estimates
    253: .  nest   - number of error estimates to display
    254: -  vf     - viewer and format for monitoring

    256:    Options Database Key:
    257: .  -svd_monitor_conv - activates `SVDMonitorConverged()`

    259:    Notes:
    260:    This is not called directly by users, rather one calls `SVDMonitorSet()`, with this
    261:    function as an argument, to cause the monitor to be used during the `SVD` solve.

    263:    Call `SVDMonitorConvergedCreate()` to create the context used with this monitor.

    265:    Level: intermediate

    267: .seealso: [](ch:svd), `SVDMonitorSet()`, `SVDMonitorConvergedCreate()`, `SVDMonitorFirst()`, `SVDMonitorConditioning()`, `SVDMonitorAll()`
    268: @*/
    269: PetscErrorCode SVDMonitorConverged(SVD svd,PetscInt its,PetscInt nconv,PetscReal sigma[],PetscReal errest[],PetscInt nest,PetscViewerAndFormat *vf)
    270: {
    271:   PetscInt       i,*oldnconv;
    272:   PetscViewer    viewer = vf->viewer;

    274:   PetscFunctionBegin;
    277:   oldnconv = (PetscInt*)vf->data;
    278:   if (its==1 && ((PetscObject)svd)->prefix) PetscCall(PetscViewerASCIIPrintf(viewer,"  Convergence history for %s solve.\n",((PetscObject)svd)->prefix));
    279:   if (its==1) *oldnconv = 0;
    280:   if (*oldnconv!=nconv) {
    281:     PetscCall(PetscViewerPushFormat(viewer,vf->format));
    282:     PetscCall(PetscViewerASCIIAddTab(viewer,((PetscObject)svd)->tablevel));
    283:     for (i=*oldnconv;i<nconv;i++) {
    284:       PetscCall(PetscViewerASCIIPrintf(viewer,"%3" PetscInt_FMT " SVD converged value (error) #%" PetscInt_FMT,its,i));
    285:       PetscCall(PetscViewerASCIIUseTabs(viewer,PETSC_FALSE));
    286:       PetscCall(PetscViewerASCIIPrintf(viewer," %g (%10.8e)\n",(double)sigma[i],(double)errest[i]));
    287:       PetscCall(PetscViewerASCIIUseTabs(viewer,PETSC_TRUE));
    288:     }
    289:     PetscCall(PetscViewerASCIISubtractTab(viewer,((PetscObject)svd)->tablevel));
    290:     PetscCall(PetscViewerPopFormat(viewer));
    291:     *oldnconv = nconv;
    292:   }
    293:   PetscFunctionReturn(PETSC_SUCCESS);
    294: }

    296: /*@C
    297:    SVDMonitorConvergedCreate - Creates the context for the convergence history monitor.

    299:    Collective

    301:    Input Parameters:
    302: +  viewer - the viewer
    303: .  format - the viewer format
    304: -  ctx    - an optional user context

    306:    Output Parameter:
    307: .  vf     - the viewer and format context

    309:    Level: intermediate

    311: .seealso: [](ch:svd), `SVDMonitorSet()`
    312: @*/
    313: PetscErrorCode SVDMonitorConvergedCreate(PetscViewer viewer,PetscViewerFormat format,PetscCtx ctx,PetscViewerAndFormat **vf)
    314: {
    315:   PetscInt *oldnconv;

    317:   PetscFunctionBegin;
    318:   PetscCall(PetscViewerAndFormatCreate(viewer,format,vf));
    319:   PetscCall(PetscNew(&oldnconv));
    320:   (*vf)->data = (void*)oldnconv;
    321:   (*vf)->data_destroy = PetscCtxDestroyDefault;
    322:   PetscFunctionReturn(PETSC_SUCCESS);
    323: }

    325: /*@C
    326:    SVDMonitorFirstDrawLG - Plots the error estimate of the first unconverged
    327:    approximation at each iteration of the singular value solver.

    329:    Collective

    331:    Input Parameters:
    332: +  svd    - the singular value solver context
    333: .  its    - iteration number
    334: .  nconv  - number of converged singular triplets so far
    335: .  sigma  - singular values
    336: .  errest - error estimates
    337: .  nest   - number of error estimates to display
    338: -  vf     - viewer and format for monitoring

    340:    Options Database Key:
    341: .  -svd_monitor draw::draw_lg - activates `SVDMonitorFirstDrawLG()`

    343:    Notes:
    344:    This is not called directly by users, rather one calls `SVDMonitorSet()`, with this
    345:    function as an argument, to cause the monitor to be used during the `SVD` solve.

    347:    Call `SVDMonitorFirstDrawLGCreate()` to create the context used with this monitor.

    349:    Level: intermediate

    351: .seealso: [](ch:svd), `SVDMonitorSet()`, `SVDMonitorFirstDrawLGCreate()`
    352: @*/
    353: PetscErrorCode SVDMonitorFirstDrawLG(SVD svd,PetscInt its,PetscInt nconv,PetscReal sigma[],PetscReal errest[],PetscInt nest,PetscViewerAndFormat *vf)
    354: {
    355:   PetscViewer    viewer = vf->viewer;
    356:   PetscDrawLG    lg;
    357:   PetscReal      x,y;

    359:   PetscFunctionBegin;
    362:   PetscCall(PetscViewerPushFormat(viewer,vf->format));
    363:   PetscCall(PetscViewerDrawGetDrawLG(viewer,0,&lg));
    364:   if (its==1) {
    365:     PetscCall(PetscDrawLGReset(lg));
    366:     PetscCall(PetscDrawLGSetDimension(lg,1));
    367:     PetscCall(PetscDrawLGSetLimits(lg,1,1,PetscLog10Real(svd->tol)-2,0.0));
    368:   }
    369:   if (nconv<nest) {
    370:     x = (PetscReal)its;
    371:     if (errest[nconv] > 0.0) y = PetscLog10Real(errest[nconv]);
    372:     else y = 0.0;
    373:     PetscCall(PetscDrawLGAddPoint(lg,&x,&y));
    374:     if (its <= 20 || !(its % 5) || svd->reason) {
    375:       PetscCall(PetscDrawLGDraw(lg));
    376:       PetscCall(PetscDrawLGSave(lg));
    377:     }
    378:   }
    379:   PetscCall(PetscViewerPopFormat(viewer));
    380:   PetscFunctionReturn(PETSC_SUCCESS);
    381: }

    383: /*@C
    384:    SVDMonitorFirstDrawLGCreate - Creates the plotter for the first error estimate.

    386:    Collective

    388:    Input Parameters:
    389: +  viewer - the viewer
    390: .  format - the viewer format
    391: -  ctx    - an optional user context

    393:    Output Parameter:
    394: .  vf     - the viewer and format context

    396:    Level: intermediate

    398: .seealso: [](ch:svd), `SVDMonitorSet()`
    399: @*/
    400: PetscErrorCode SVDMonitorFirstDrawLGCreate(PetscViewer viewer,PetscViewerFormat format,void *ctx,PetscViewerAndFormat **vf)
    401: {
    402:   PetscFunctionBegin;
    403:   PetscCall(PetscViewerAndFormatCreate(viewer,format,vf));
    404:   (*vf)->data = ctx;
    405:   PetscCall(PetscViewerMonitorLGSetUp(viewer,NULL,"First Error Estimate","Log Error Estimate",1,NULL,PETSC_DECIDE,PETSC_DECIDE,400,300));
    406:   PetscFunctionReturn(PETSC_SUCCESS);
    407: }

    409: /*@C
    410:    SVDMonitorAllDrawLG - Plots the error estimate of all unconverged
    411:    approximations at each iteration of the singular value solver.

    413:    Collective

    415:    Input Parameters:
    416: +  svd    - the singular value solver context
    417: .  its    - iteration number
    418: .  nconv  - number of converged singular triplets so far
    419: .  sigma  - singular values
    420: .  errest - error estimates
    421: .  nest   - number of error estimates to display
    422: -  vf     - viewer and format for monitoring

    424:    Options Database Key:
    425: .  -svd_monitor_all draw::draw_lg - activates `SVDMonitorAllDrawLG()`

    427:    Notes:
    428:    This is not called directly by users, rather one calls `SVDMonitorSet()`, with this
    429:    function as an argument, to cause the monitor to be used during the `SVD` solve.

    431:    Call `SVDMonitorAllDrawLGCreate()` to create the context used with this monitor.

    433:    Level: intermediate

    435: .seealso: [](ch:svd), `SVDMonitorSet()`, `SVDMonitorAllDrawLGCreate()`
    436: @*/
    437: PetscErrorCode SVDMonitorAllDrawLG(SVD svd,PetscInt its,PetscInt nconv,PetscReal sigma[],PetscReal errest[],PetscInt nest,PetscViewerAndFormat *vf)
    438: {
    439:   PetscViewer    viewer = vf->viewer;
    440:   PetscDrawLG    lg;
    441:   PetscInt       i,n = PetscMin(svd->nsv,255);
    442:   PetscReal      *x,*y;

    444:   PetscFunctionBegin;
    447:   PetscCall(PetscViewerPushFormat(viewer,vf->format));
    448:   PetscCall(PetscViewerDrawGetDrawLG(viewer,0,&lg));
    449:   if (its==1) {
    450:     PetscCall(PetscDrawLGReset(lg));
    451:     PetscCall(PetscDrawLGSetDimension(lg,n));
    452:     PetscCall(PetscDrawLGSetLimits(lg,1,1,PetscLog10Real(svd->tol)-2,0.0));
    453:   }
    454:   PetscCall(PetscMalloc2(n,&x,n,&y));
    455:   for (i=0;i<n;i++) {
    456:     x[i] = (PetscReal)its;
    457:     if (i < nest && errest[i] > 0.0) y[i] = PetscLog10Real(errest[i]);
    458:     else y[i] = 0.0;
    459:   }
    460:   PetscCall(PetscDrawLGAddPoint(lg,x,y));
    461:   if (its <= 20 || !(its % 5) || svd->reason) {
    462:     PetscCall(PetscDrawLGDraw(lg));
    463:     PetscCall(PetscDrawLGSave(lg));
    464:   }
    465:   PetscCall(PetscFree2(x,y));
    466:   PetscCall(PetscViewerPopFormat(viewer));
    467:   PetscFunctionReturn(PETSC_SUCCESS);
    468: }

    470: /*@C
    471:    SVDMonitorAllDrawLGCreate - Creates the plotter for all the error estimates.

    473:    Collective

    475:    Input Parameters:
    476: +  viewer - the viewer
    477: .  format - the viewer format
    478: -  ctx    - an optional user context

    480:    Output Parameter:
    481: .  vf     - the viewer and format context

    483:    Level: intermediate

    485: .seealso: [](ch:svd), `SVDMonitorSet()`
    486: @*/
    487: PetscErrorCode SVDMonitorAllDrawLGCreate(PetscViewer viewer,PetscViewerFormat format,void *ctx,PetscViewerAndFormat **vf)
    488: {
    489:   PetscFunctionBegin;
    490:   PetscCall(PetscViewerAndFormatCreate(viewer,format,vf));
    491:   (*vf)->data = ctx;
    492:   PetscCall(PetscViewerMonitorLGSetUp(viewer,NULL,"All Error Estimates","Log Error Estimate",1,NULL,PETSC_DECIDE,PETSC_DECIDE,400,300));
    493:   PetscFunctionReturn(PETSC_SUCCESS);
    494: }

    496: /*@C
    497:    SVDMonitorConvergedDrawLG - Plots the number of converged eigenvalues
    498:    at each iteration of the singular value solver.

    500:    Collective

    502:    Input Parameters:
    503: +  svd    - the singular value solver context
    504: .  its    - iteration number
    505: .  nconv  - number of converged singular triplets so far
    506: .  sigma  - singular values
    507: .  errest - error estimates
    508: .  nest   - number of error estimates to display
    509: -  vf     - viewer and format for monitoring

    511:    Options Database Key:
    512: .  -svd_monitor_conv draw::draw_lg - activates `SVDMonitorConvergedDrawLG()`

    514:    Notes:
    515:    This is not called directly by users, rather one calls `SVDMonitorSet()`, with this
    516:    function as an argument, to cause the monitor to be used during the `SVD` solve.

    518:    Call `SVDMonitorConvergedDrawLGCreate()` to create the context used with this monitor.

    520:    Level: intermediate

    522: .seealso: [](ch:svd), `SVDMonitorSet()`, `SVDMonitorConvergedDrawLGCreate()`
    523: @*/
    524: PetscErrorCode SVDMonitorConvergedDrawLG(SVD svd,PetscInt its,PetscInt nconv,PetscReal sigma[],PetscReal errest[],PetscInt nest,PetscViewerAndFormat *vf)
    525: {
    526:   PetscViewer      viewer = vf->viewer;
    527:   PetscDrawLG      lg;
    528:   PetscReal        x,y;

    530:   PetscFunctionBegin;
    533:   PetscCall(PetscViewerPushFormat(viewer,vf->format));
    534:   PetscCall(PetscViewerDrawGetDrawLG(viewer,0,&lg));
    535:   if (its==1) {
    536:     PetscCall(PetscDrawLGReset(lg));
    537:     PetscCall(PetscDrawLGSetDimension(lg,1));
    538:     PetscCall(PetscDrawLGSetLimits(lg,1,1,0,svd->nsv));
    539:   }
    540:   x = (PetscReal)its;
    541:   y = (PetscReal)svd->nconv;
    542:   PetscCall(PetscDrawLGAddPoint(lg,&x,&y));
    543:   if (its <= 20 || !(its % 5) || svd->reason) {
    544:     PetscCall(PetscDrawLGDraw(lg));
    545:     PetscCall(PetscDrawLGSave(lg));
    546:   }
    547:   PetscCall(PetscViewerPopFormat(viewer));
    548:   PetscFunctionReturn(PETSC_SUCCESS);
    549: }

    551: /*@C
    552:    SVDMonitorConvergedDrawLGCreate - Creates the plotter for the convergence history.

    554:    Collective

    556:    Input Parameters:
    557: +  viewer - the viewer
    558: .  format - the viewer format
    559: -  ctx    - an optional user context

    561:    Output Parameter:
    562: .  vf     - the viewer and format context

    564:    Level: intermediate

    566: .seealso: [](ch:svd), `SVDMonitorSet()`
    567: @*/
    568: PetscErrorCode SVDMonitorConvergedDrawLGCreate(PetscViewer viewer,PetscViewerFormat format,void *ctx,PetscViewerAndFormat **vf)
    569: {
    570:   PetscInt *oldnconv;

    572:   PetscFunctionBegin;
    573:   PetscCall(PetscViewerAndFormatCreate(viewer,format,vf));
    574:   PetscCall(PetscNew(&oldnconv));
    575:   (*vf)->data = (void*)oldnconv;
    576:   (*vf)->data_destroy = PetscCtxDestroyDefault;
    577:   PetscCall(PetscViewerMonitorLGSetUp(viewer,NULL,"Convergence History","Number Converged",1,NULL,PETSC_DECIDE,PETSC_DECIDE,400,300));
    578:   PetscFunctionReturn(PETSC_SUCCESS);
    579: }

    581: /*@C
    582:    SVDMonitorConditioning - Print the condition number at each iteration of the singular
    583:    value solver.

    585:    Collective

    587:    Input Parameters:
    588: +  svd    - the singular value solver context
    589: .  its    - iteration number
    590: .  nconv  - (unused) number of converged singular triplets so far
    591: .  sigma  - (unused) singular values
    592: .  errest - (unused) error estimates
    593: .  nest   - (unused) number of error estimates to display
    594: -  vf     - viewer and format for monitoring

    596:    Options Database Key:
    597: .  -svd_monitor_conditioning - activates `SVDMonitorConditioning()`

    599:    Notes:
    600:    This is not called directly by users, rather one calls `SVDMonitorSet()`, with this
    601:    function as an argument, to cause the monitor to be used during the `SVD` solve.

    603:    Works only for solvers that use a `DS` of type `DSGSVD`. The printed information corresponds
    604:    to the maximum of the condition number of the two generated bidiagonal matrices.

    606:    Level: intermediate

    608: .seealso: [](ch:svd), `SVDMonitorSet()`, `SVDMonitorAll()`, `SVDMonitorFirst()`, `SVDMonitorConverged()`
    609: @*/
    610: PetscErrorCode SVDMonitorConditioning(SVD svd,PetscInt its,PetscInt nconv,PetscReal sigma[],PetscReal errest[],PetscInt nest,PetscViewerAndFormat *vf)
    611: {
    612:   PetscViewer viewer = vf->viewer;
    613:   PetscBool   isgsvd;
    614:   PetscReal   cond;

    616:   PetscFunctionBegin;
    619:   PetscCall(PetscObjectTypeCompare((PetscObject)svd->ds,DSGSVD,&isgsvd));
    620:   if (!isgsvd) PetscFunctionReturn(PETSC_SUCCESS);
    621:   if (its==1 && ((PetscObject)svd)->prefix) PetscCall(PetscViewerASCIIPrintf(viewer,"  Condition number of bidiagonal matrices for %s solve.\n",((PetscObject)svd)->prefix));
    622:   PetscCall(PetscViewerPushFormat(viewer,vf->format));
    623:   PetscCall(PetscViewerASCIIAddTab(viewer,((PetscObject)svd)->tablevel));
    624:   PetscCall(DSCond(svd->ds,&cond));
    625:   PetscCall(PetscViewerASCIIPrintf(viewer,"%3" PetscInt_FMT " SVD condition number = %g\n",its,(double)cond));
    626:   PetscCall(PetscViewerASCIISubtractTab(viewer,((PetscObject)svd)->tablevel));
    627:   PetscCall(PetscViewerPopFormat(viewer));
    628:   PetscFunctionReturn(PETSC_SUCCESS);
    629: }