Date: 2017-05-17T08:25:28+00:00

Actual source code: rginterval.c
slepc-3.7.4 2017-05-17
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      1: /*
      2:    Interval of the real axis or more generally a (possibly open) rectangle
      3:    of the complex plane.

      5:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      6:    SLEPc - Scalable Library for Eigenvalue Problem Computations
      7:    Copyright (c) 2002-2016, Universitat Politecnica de Valencia, Spain

      9:    This file is part of SLEPc.

     11:    SLEPc is free software: you can redistribute it and/or modify it under  the
     12:    terms of version 3 of the GNU Lesser General Public License as published by
     13:    the Free Software Foundation.

     15:    SLEPc  is  distributed in the hope that it will be useful, but WITHOUT  ANY
     16:    WARRANTY;  without even the implied warranty of MERCHANTABILITY or  FITNESS
     17:    FOR  A  PARTICULAR PURPOSE. See the GNU Lesser General Public  License  for
     18:    more details.

     20:    You  should have received a copy of the GNU Lesser General  Public  License
     21:    along with SLEPc. If not, see <http://www.gnu.org/licenses/>.
     22:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     23: */

     25: #include <slepc/private/rgimpl.h>      /*I "slepcrg.h" I*/

     27: typedef struct {
     28:   PetscReal   a,b;     /* interval in the real axis */
     29:   PetscReal   c,d;     /* interval in the imaginary axis */
     30: } RG_INTERVAL;

     34: static PetscErrorCode RGIntervalSetEndpoints_Interval(RG rg,PetscReal a,PetscReal b,PetscReal c,PetscReal d)
     35: {
     36:   RG_INTERVAL *ctx = (RG_INTERVAL*)rg->data;

     39:   if (!a && !b && !c && !d) SETERRQ(PetscObjectComm((PetscObject)rg),PETSC_ERR_ARG_WRONG,"At least one argument must be nonzero");
     40:   if (a==b && a) SETERRQ(PetscObjectComm((PetscObject)rg),PETSC_ERR_ARG_WRONG,"Badly defined interval, endpoints must be distinct (or both zero)");
     41:   if (a>b) SETERRQ(PetscObjectComm((PetscObject)rg),PETSC_ERR_ARG_WRONG,"Badly defined interval, must be a<b");
     42:   if (c==d && c) SETERRQ(PetscObjectComm((PetscObject)rg),PETSC_ERR_ARG_WRONG,"Badly defined interval, endpoints must be distinct (or both zero)");
     43:   if (c>d) SETERRQ(PetscObjectComm((PetscObject)rg),PETSC_ERR_ARG_WRONG,"Badly defined interval, must be c<d");
     44: #if !defined(PETSC_USE_COMPLEX)
     45:   if (c!=-d) SETERRQ(PetscObjectComm((PetscObject)rg),PETSC_ERR_ARG_WRONG,"In real scalars the region must be symmetric wrt real axis");
     46: #endif
     47:   ctx->a = a;
     48:   ctx->b = b;
     49:   ctx->c = c;
     50:   ctx->d = d;
     51:   return(0);
     52: }

     56: /*@
     57:    RGIntervalSetEndpoints - Sets the parameters defining the interval region.

     59:    Logically Collective on RG

     61:    Input Parameters:
     62: +  rg  - the region context
     63: .  a,b - endpoints of the interval in the real axis
     64: -  c,d - endpoints of the interval in the imaginary axis

     66:    Options Database Keys:
     67: .  -rg_interval_endpoints - the four endpoints

     69:    Note:
     70:    The region is defined as [a,b]x[c,d]. Particular cases are an interval on
     71:    the real axis (c=d=0), similar for the imaginary axis (a=b=0), the whole
     72:    complex plane (a=-inf,b=inf,c=-inf,d=inf), and so on.

     74:    Level: advanced

     76: .seealso: RGIntervalGetEndpoints()
     77: @*/
     78: PetscErrorCode RGIntervalSetEndpoints(RG rg,PetscReal a,PetscReal b,PetscReal c,PetscReal d)
     79: {

     88:   PetscTryMethod(rg,"RGIntervalSetEndpoints_C",(RG,PetscReal,PetscReal,PetscReal,PetscReal),(rg,a,b,c,d));
     89:   return(0);
     90: }

     94: static PetscErrorCode RGIntervalGetEndpoints_Interval(RG rg,PetscReal *a,PetscReal *b,PetscReal *c,PetscReal *d)
     95: {
     96:   RG_INTERVAL *ctx = (RG_INTERVAL*)rg->data;

     99:   if (a) *a = ctx->a;
    100:   if (b) *b = ctx->b;
    101:   if (c) *c = ctx->c;
    102:   if (d) *d = ctx->d;
    103:   return(0);
    104: }

    108: /*@
    109:    RGIntervalGetEndpoints - Gets the parameters that define the interval region.

    111:    Not Collective

    113:    Input Parameter:
    114: .  rg - the region context

    116:    Output Parameters:
    117: +  a,b - endpoints of the interval in the real axis
    118: -  c,d - endpoints of the interval in the imaginary axis

    120:    Level: advanced

    122: .seealso: RGIntervalSetEndpoints()
    123: @*/
    124: PetscErrorCode RGIntervalGetEndpoints(RG rg,PetscReal *a,PetscReal *b,PetscReal *c,PetscReal *d)
    125: {

    130:   PetscUseMethod(rg,"RGIntervalGetEndpoints_C",(RG,PetscReal*,PetscReal*,PetscReal*,PetscReal*),(rg,a,b,c,d));
    131:   return(0);
    132: }

    136: PetscErrorCode RGView_Interval(RG rg,PetscViewer viewer)
    137: {
    139:   RG_INTERVAL    *ctx = (RG_INTERVAL*)rg->data;
    140:   PetscBool      isascii;

    143:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&isascii);
    144:   if (isascii) {
    145:     PetscViewerASCIIPrintf(viewer,"region: [%g,%g]x[%g,%g]\n",RGShowReal(ctx->a),RGShowReal(ctx->b),RGShowReal(ctx->c),RGShowReal(ctx->d));
    146:   }
    147:   return(0);
    148: }

    152: PetscErrorCode RGIsTrivial_Interval(RG rg,PetscBool *trivial)
    153: {
    154:   RG_INTERVAL *ctx = (RG_INTERVAL*)rg->data;

    157:   if (rg->complement) *trivial = (ctx->a==ctx->b && ctx->c==ctx->d)? PETSC_TRUE: PETSC_FALSE;
    158:   else *trivial = (ctx->a<=-PETSC_MAX_REAL && ctx->b>=PETSC_MAX_REAL && ctx->c<=-PETSC_MAX_REAL && ctx->d>=PETSC_MAX_REAL)? PETSC_TRUE: PETSC_FALSE;
    159:   return(0);
    160: }

    164: PetscErrorCode RGComputeContour_Interval(RG rg,PetscInt n,PetscScalar *cr,PetscScalar *ci)
    165: {
    166:   RG_INTERVAL *ctx = (RG_INTERVAL*)rg->data;
    167:   PetscInt    i,pt,idx,j;
    168:   PetscReal   hr[4],hi[4],h,off,d[4];
    169:   PetscScalar vr[4],vi[4];

    172:   if (!(ctx->a>-PETSC_MAX_REAL && ctx->b<PETSC_MAX_REAL && ctx->c>-PETSC_MAX_REAL && ctx->d<PETSC_MAX_REAL)) SETERRQ(PetscObjectComm((PetscObject)rg),PETSC_ERR_SUP,"Contour not defined in unbounded regions");
    173:   if (ctx->a==ctx->b || ctx->c==ctx->d) {
    174:     if (ctx->a==ctx->b) {hi[0] = (ctx->d-ctx->c)/(n-1); hr[0] = 0.0;}
    175:     else {hr[0] = (ctx->b-ctx->a)/(n-1); hi[0] = 0.0;}
    176:     for (i=0;i<n;i++) {
    177: #if defined(PETSC_USE_COMPLEX)
    178:       cr[i] = ctx->a+hr[0]*i + (ctx->c+hi[0]*i)*PETSC_i;
    179: #else
    180:       cr[i] = ctx->a+hr[0]*i; ci[i] = ctx->c+hi[0]*i;
    181: #endif
    182:     }
    183:   } else {
    184:     d[1] = d[3] = ctx->d-ctx->c; d[0] = d[2] = ctx->b-ctx->a;
    185:     h = (2*(d[0]+d[1]))/n;
    186:     vr[0] = ctx->a; vr[1] = ctx->b; vr[2] = ctx->b; vr[3] = ctx->a;
    187:     vi[0] = ctx->c; vi[1] = ctx->c; vi[2] = ctx->d; vi[3] = ctx->d;
    188:     hr[0] = h;   hr[1] = 0.0; hr[2] = -h;  hr[3] = 0.0;
    189:     hi[0] = 0.0; hi[1] = h;   hi[2] = 0.0; hi[3] = -h;
    190:     off = 0.0; idx = 0;
    191:     for (i=0;i<4;i++) {
    192: #if defined(PETSC_USE_COMPLEX)
    193:       cr[idx] = vr[i]+off*(hr[i]/h)+ (vi[i]+off*(hi[i]/h))*PETSC_i;
    194: #else
    195:       cr[idx] = vr[i]+off*(hr[i]/h); ci[idx]=vi[i]+off*(hi[i]/h);
    196: #endif
    197:       idx++;
    198:       pt = (d[i]-off)/h+1;
    199:       for (j=1;j<pt && idx<n;j++) {
    200: #if defined(PETSC_USE_COMPLEX)
    201:         cr[idx] = cr[idx-1]+(hr[i]+hi[i]*PETSC_i);
    202: #else
    203:         cr[idx] = cr[idx-1]+hr[i]; ci[idx] = ci[idx-1]+hi[i];
    204: #endif
    205:         idx++;
    206:       }
    207:       off = off+pt*h-d[i];
    208:       if (off>=d[i+1]) {off -= d[i+1]; i++;}
    209:     }
    210:   }
    211:   return(0);
    212: }

    216: PetscErrorCode RGCheckInside_Interval(RG rg,PetscReal dx,PetscReal dy,PetscInt *inside)
    217: {
    218:   RG_INTERVAL *ctx = (RG_INTERVAL*)rg->data;

    221:   if (dx>ctx->a && dx<ctx->b) *inside = 1;
    222:   else if (dx==ctx->a || dx==ctx->b) *inside = 0;
    223:   else *inside = -1;
    224:   if (*inside>=0) {
    225:     if (dy>ctx->c && dy<ctx->d) ;
    226:     else if (dy==ctx->c || dy==ctx->d) *inside = 0;
    227:     else *inside = -1;
    228:   }
    229:   return(0);
    230: }

    234: PetscErrorCode RGSetFromOptions_Interval(PetscOptionItems *PetscOptionsObject,RG rg)
    235: {
    237:   PetscBool      flg;
    238:   PetscInt       k;
    239:   PetscReal      array[4]={0,0,0,0};

    242:   PetscOptionsHead(PetscOptionsObject,"RG Interval Options");

    244:   k = 4;
    245:   PetscOptionsRealArray("-rg_interval_endpoints","Interval endpoints (four real values separated with a comma without spaces)","RGIntervalSetEndpoints",array,&k,&flg);
    246:   if (flg) {
    247:     if (k<2) SETERRQ(PetscObjectComm((PetscObject)rg),PETSC_ERR_ARG_SIZ,"Must pass at leat two values in -rg_interval_endpoints (comma-separated without spaces)");
    248:     RGIntervalSetEndpoints(rg,array[0],array[1],array[2],array[3]);
    249:   }

    251:   PetscOptionsTail();
    252:   return(0);
    253: }

    257: PetscErrorCode RGDestroy_Interval(RG rg)
    258: {

    262:   PetscFree(rg->data);
    263:   PetscObjectComposeFunction((PetscObject)rg,"RGIntervalSetEndpoints_C",NULL);
    264:   PetscObjectComposeFunction((PetscObject)rg,"RGIntervalGetEndpoints_C",NULL);
    265:   return(0);
    266: }

    270: PETSC_EXTERN PetscErrorCode RGCreate_Interval(RG rg)
    271: {
    272:   RG_INTERVAL    *interval;

    276:   PetscNewLog(rg,&interval);
    277:   interval->a = -PETSC_MAX_REAL;
    278:   interval->b = PETSC_MAX_REAL;
    279:   interval->c = -PETSC_MAX_REAL;
    280:   interval->d = PETSC_MAX_REAL;
    281:   rg->data = (void*)interval;

    283:   rg->ops->istrivial      = RGIsTrivial_Interval;
    284:   rg->ops->computecontour = RGComputeContour_Interval;
    285:   rg->ops->checkinside    = RGCheckInside_Interval;
    286:   rg->ops->setfromoptions = RGSetFromOptions_Interval;
    287:   rg->ops->view           = RGView_Interval;
    288:   rg->ops->destroy        = RGDestroy_Interval;
    289:   PetscObjectComposeFunction((PetscObject)rg,"RGIntervalSetEndpoints_C",RGIntervalSetEndpoints_Interval);
    290:   PetscObjectComposeFunction((PetscObject)rg,"RGIntervalGetEndpoints_C",RGIntervalGetEndpoints_Interval);
    291:   return(0);
    292: }