C++ PetscSqrtReal函数代码示例

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本文整理汇总了C++中PetscSqrtReal函数的典型用法代码示例。如果您正苦于以下问题：C++ PetscSqrtReal函数的具体用法？C++ PetscSqrtReal怎么用？C++ PetscSqrtReal使用的例子？那么恭喜您, 这里精选的函数代码示例或许可以为您提供帮助。

在下文中一共展示了PetscSqrtReal函数的20个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于我们的系统推荐出更棒的C++代码示例。

示例1: step

/*
   Monitor - User-provided routine to monitor the solution computed at
   each timestep.  This example plots the solution and computes the
   error in two different norms.

   Input Parameters:
   ts     - the timestep context
   step   - the count of the current step (with 0 meaning the
            initial condition)
   time   - the current time
   u      - the solution at this timestep
   ctx    - the user-provided context for this monitoring routine.
            In this case we use the application context which contains
            information about the problem size, workspace and the exact
            solution.
*/
PetscErrorCode Monitor(TS ts,PetscInt step,PetscReal time,Vec u,void *ctx)
{
  AppCtx         *appctx = (AppCtx*) ctx;   /* user-defined application context */
  PetscErrorCode ierr;
  PetscReal      en2,en2s,enmax;
  PetscDraw      draw;

  /*
     We use the default X windows viewer
             PETSC_VIEWER_DRAW_(appctx->comm)
     that is associated with the current communicator. This saves
     the effort of calling PetscViewerDrawOpen() to create the window.
     Note that if we wished to plot several items in separate windows we
     would create each viewer with PetscViewerDrawOpen() and store them in
     the application context, appctx.

     PetscReal buffering makes graphics look better.
  */
  ierr = PetscViewerDrawGetDraw(PETSC_VIEWER_DRAW_(appctx->comm),0,&draw);CHKERRQ(ierr);
  ierr = PetscDrawSetDoubleBuffer(draw);CHKERRQ(ierr);
  ierr = VecView(u,PETSC_VIEWER_DRAW_(appctx->comm));CHKERRQ(ierr);

  /*
     Compute the exact solution at this timestep
  */
  ierr = ExactSolution(time,appctx->solution,appctx);CHKERRQ(ierr);

  /*
     Print debugging information if desired
  */
  if (appctx->debug) {
    ierr = PetscPrintf(appctx->comm,"Computed solution vector\n");CHKERRQ(ierr);
    ierr = VecView(u,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
    ierr = PetscPrintf(appctx->comm,"Exact solution vector\n");CHKERRQ(ierr);
    ierr = VecView(appctx->solution,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
  }

  /*
     Compute the 2-norm and max-norm of the error
  */
  ierr = VecAXPY(appctx->solution,-1.0,u);CHKERRQ(ierr);
  ierr = VecNorm(appctx->solution,NORM_2,&en2);CHKERRQ(ierr);
  en2s = PetscSqrtReal(appctx->h)*en2;  /* scale the 2-norm by the grid spacing */
  ierr = VecNorm(appctx->solution,NORM_MAX,&enmax);CHKERRQ(ierr);

  /*
     PetscPrintf() causes only the first processor in this
     communicator to print the timestep information.
  */
  ierr = PetscPrintf(appctx->comm,"Timestep %D: time = %g,2-norm error = %g, max norm error = %g\n",step,(double)time,(double)en2s,(double)enmax);CHKERRQ(ierr);

  /*
     Print debugging information if desired
   */
  /*  if (appctx->debug) {
     ierr = PetscPrintf(appctx->comm,"Error vector\n");CHKERRQ(ierr);
     ierr = VecView(appctx->solution,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
   } */
  return 0;
}

开发者ID:masa-ito，项目名称:PETScToPoisson，代码行数:76，代码来源:ex21.c

示例2: FormInitialGuess

PetscErrorCode FormInitialGuess(Vec X,AppCtx *user)
{
  PetscInt       i,j,row,mx,my;
  PetscErrorCode ierr;
  PetscReal      one = 1.0,lambda;
  PetscReal      temp1,temp,hx,hy;
  PetscScalar    *x;

  mx	 = user->mx; 
  my	 = user->my;
  lambda = user->param;

  hx    = one / (PetscReal)(mx-1);
  hy    = one / (PetscReal)(my-1);

  ierr = VecGetArray(X,&x);CHKERRQ(ierr);
  temp1 = lambda/(lambda + one);
  for (j=0; j<my; j++) {
    temp = (PetscReal)(PetscMin(j,my-j-1))*hy;
    for (i=0; i<mx; i++) {
      row = i + j*mx;  
      if (i == 0 || j == 0 || i == mx-1 || j == my-1) {
        x[row] = 0.0; 
        continue;
      }
      x[row] = temp1*PetscSqrtReal(PetscMin((PetscReal)(PetscMin(i,mx-i-1))*hx,temp)); 
    }
  }
  ierr = VecRestoreArray(X,&x);CHKERRQ(ierr);
  return 0;
}

开发者ID:Kun-Qu，项目名称:petsc，代码行数:31，代码来源:ex1.c

示例3: StokesCalcError

PetscErrorCode StokesCalcError(Stokes *s)
{
  PetscScalar    scale = PetscSqrtReal((double)s->nx*s->ny);
  PetscReal      val;
  Vec            y0, y1;
  PetscErrorCode ierr;

  PetscFunctionBeginUser;
  /* error y-x */
  ierr = VecAXPY(s->y, -1.0, s->x);CHKERRQ(ierr);
  /* ierr = VecView(s->y, (PetscViewer)PETSC_VIEWER_DEFAULT);CHKERRQ(ierr); */

  /* error in velocity */
  ierr = VecGetSubVector(s->y, s->isg[0], &y0);CHKERRQ(ierr);
  ierr = VecNorm(y0, NORM_2, &val);CHKERRQ(ierr);
  ierr = PetscPrintf(PETSC_COMM_WORLD," discretization error u = %g\n",(double)(PetscRealPart(val/scale)));CHKERRQ(ierr);
  ierr = VecRestoreSubVector(s->y, s->isg[0], &y0);CHKERRQ(ierr);

  /* error in pressure */
  ierr = VecGetSubVector(s->y, s->isg[1], &y1);CHKERRQ(ierr);
  ierr = VecNorm(y1, NORM_2, &val);CHKERRQ(ierr);
  ierr = PetscPrintf(PETSC_COMM_WORLD," discretization error p = %g\n",(double)(PetscRealPart(val/scale)));CHKERRQ(ierr);
  ierr = VecRestoreSubVector(s->y, s->isg[1], &y1);CHKERRQ(ierr);

  /* total error */
  ierr = VecNorm(s->y, NORM_2, &val);CHKERRQ(ierr);
  ierr = PetscPrintf(PETSC_COMM_WORLD," discretization error [u,p] = %g\n", (double)PetscRealPart((val/scale)));CHKERRQ(ierr);
  PetscFunctionReturn(0);
}

开发者ID:FeMTTU，项目名称:femus，代码行数:29，代码来源:ex4.cpp

示例4: interval

/*@
   PetscDTGaussQuadrature - create Gauss quadrature

   Not Collective

   Input Arguments:
+  npoints - number of points
.  a - left end of interval (often-1)
-  b - right end of interval (often +1)

   Output Arguments:
+  x - quadrature points
-  w - quadrature weights

   Level: intermediate

   References:
   Golub and Welsch, Calculation of Quadrature Rules, Math. Comp. 23(106), 221--230, 1969.

.seealso: PetscDTLegendreEval()
@*/
PetscErrorCode PetscDTGaussQuadrature(PetscInt npoints,PetscReal a,PetscReal b,PetscReal *x,PetscReal *w)
{
  PetscErrorCode ierr;
  PetscInt       i;
  PetscReal      *work;
  PetscScalar    *Z;
  PetscBLASInt   N,LDZ,info;

  PetscFunctionBegin;
  ierr = PetscCitationsRegister(GaussCitation, &GaussCite);CHKERRQ(ierr);
  /* Set up the Golub-Welsch system */
  for (i=0; i<npoints; i++) {
    x[i] = 0;                   /* diagonal is 0 */
    if (i) w[i-1] = 0.5 / PetscSqrtReal(1 - 1./PetscSqr(2*i));
  }
  ierr = PetscMalloc2(npoints*npoints,&Z,PetscMax(1,2*npoints-2),&work);CHKERRQ(ierr);
  ierr = PetscBLASIntCast(npoints,&N);CHKERRQ(ierr);
  LDZ  = N;
  ierr = PetscFPTrapPush(PETSC_FP_TRAP_OFF);CHKERRQ(ierr);
  PetscStackCallBLAS("LAPACKsteqr",LAPACKsteqr_("I",&N,x,w,Z,&LDZ,work,&info));
  ierr = PetscFPTrapPop();CHKERRQ(ierr);
  if (info) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"xSTEQR error");

  for (i=0; i<(npoints+1)/2; i++) {
    PetscReal y = 0.5 * (-x[i] + x[npoints-i-1]); /* enforces symmetry */
    x[i]           = (a+b)/2 - y*(b-a)/2;
    x[npoints-i-1] = (a+b)/2 + y*(b-a)/2;

    w[i] = w[npoints-1-i] = 0.5*(b-a)*(PetscSqr(PetscAbsScalar(Z[i*npoints])) + PetscSqr(PetscAbsScalar(Z[(npoints-i-1)*npoints])));
  }
  ierr = PetscFree2(Z,work);CHKERRQ(ierr);
  PetscFunctionReturn(0);
}

开发者ID:00liujj，项目名称:petsc，代码行数:54，代码来源:dt.c

示例5: FormInitialGuess

/* 
   FormInitialGuess - Forms initial approximation.

   Input Parameters:
   user - user-defined application context
   X - vector

   Output Parameter:
   X - vector
 */
PetscErrorCode FormInitialGuess(AppCtx *user,Vec X)
{
  PetscInt       i,j,row,mx,my,xs,ys,xm,ym,gxm,gym,gxs,gys;
  PetscErrorCode ierr;
  PetscReal      one = 1.0,lambda,temp1,temp,hx,hy,hxdhy,hydhx,sc;
  PetscScalar    *x;
  Vec            localX = user->localX;

  mx = user->mx;            my = user->my;            lambda = user->param;
  hx = one/(PetscReal)(mx-1);  hy = one/(PetscReal)(my-1);
  sc = hx*hy*lambda;        hxdhy = hx/hy;            hydhx = hy/hx;
  temp1 = lambda/(lambda + one);

  /*
     Get a pointer to vector data.
       - For default PETSc vectors,VecGetArray() returns a pointer to
         the data array.  Otherwise, the routine is implementation dependent.
       - You MUST call VecRestoreArray() when you no longer need access to
         the array.
  */
  ierr = VecGetArray(localX,&x);CHKERRQ(ierr);

  /*
     Get local grid boundaries (for 2-dimensional DMDA):
       xs, ys   - starting grid indices (no ghost points)
       xm, ym   - widths of local grid (no ghost points)
       gxs, gys - starting grid indices (including ghost points)
       gxm, gym - widths of local grid (including ghost points)
  */
  ierr = DMDAGetCorners(user->da,&xs,&ys,PETSC_NULL,&xm,&ym,PETSC_NULL);CHKERRQ(ierr);
  ierr = DMDAGetGhostCorners(user->da,&gxs,&gys,PETSC_NULL,&gxm,&gym,PETSC_NULL);CHKERRQ(ierr);

  /*
     Compute initial guess over the locally owned part of the grid
  */
  for (j=ys; j<ys+ym; j++) {
    temp = (PetscReal)(PetscMin(j,my-j-1))*hy;
    for (i=xs; i<xs+xm; i++) {
      row = i - gxs + (j - gys)*gxm; 
      if (i == 0 || j == 0 || i == mx-1 || j == my-1) {
        x[row] = 0.0; 
        continue;
      }
      x[row] = temp1*PetscSqrtReal(PetscMin((PetscReal)(PetscMin(i,mx-i-1))*hx,temp)); 
    }
  }

  /*
     Restore vector
  */
  ierr = VecRestoreArray(localX,&x);CHKERRQ(ierr);

  /*
     Insert values into global vector
  */
  ierr = DMLocalToGlobalBegin(user->da,localX,INSERT_VALUES,X);CHKERRQ(ierr);
  ierr = DMLocalToGlobalEnd(user->da,localX,INSERT_VALUES,X);CHKERRQ(ierr);
  return 0;
}

开发者ID:Kun-Qu，项目名称:petsc，代码行数:69，代码来源:ex5.c

示例6: step

/*
   Monitor - User-provided routine to monitor the solution computed at
   each timestep.  This example plots the solution and computes the
   error in two different norms.

   Input Parameters:
   ts     - the timestep context
   step   - the count of the current step (with 0 meaning the
             initial condition)
   time   - the current time
   u      - the solution at this timestep
   ctx    - the user-provided context for this monitoring routine.
            In this case we use the application context which contains
            information about the problem size, workspace and the exact
            solution.
*/
PetscErrorCode Monitor(TS ts,PetscInt step,PetscReal time,Vec u,void *ctx)
{
  AppCtx         *appctx = (AppCtx*) ctx;   /* user-defined application context */
  PetscErrorCode ierr;
  PetscReal      norm_2,norm_max;

  /*
     View a graph of the current iterate
  */
  ierr = VecView(u,appctx->viewer2);CHKERRQ(ierr);

  /*
     Compute the exact solution
  */
  ierr = ExactSolution(time,appctx->solution,appctx);CHKERRQ(ierr);

  /*
     Print debugging information if desired
  */
  if (appctx->debug) {
    ierr = PetscPrintf(appctx->comm,"Computed solution vector\n");CHKERRQ(ierr);
    ierr = VecView(u,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
    ierr = PetscPrintf(appctx->comm,"Exact solution vector\n");CHKERRQ(ierr);
    ierr = VecView(appctx->solution,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
  }

  /*
     Compute the 2-norm and max-norm of the error
  */
  ierr   = VecAXPY(appctx->solution,-1.0,u);CHKERRQ(ierr);
  ierr   = VecNorm(appctx->solution,NORM_2,&norm_2);CHKERRQ(ierr);
  norm_2 = PetscSqrtReal(appctx->h)*norm_2;
  ierr   = VecNorm(appctx->solution,NORM_MAX,&norm_max);CHKERRQ(ierr);
  if (norm_2   < 1e-14) norm_2   = 0;
  if (norm_max < 1e-14) norm_max = 0;

  /*
     PetscPrintf() causes only the first processor in this
     communicator to print the timestep information.
  */
  ierr = PetscPrintf(appctx->comm,"Timestep %D: time = %g 2-norm error = %g max norm error = %g\n",step,(double)time,(double)norm_2,(double)norm_max);CHKERRQ(ierr);
  appctx->norm_2   += norm_2;
  appctx->norm_max += norm_max;

  /*
     View a graph of the error
  */
  ierr = VecView(appctx->solution,appctx->viewer1);CHKERRQ(ierr);

  /*
     Print debugging information if desired
  */
  if (appctx->debug) {
    ierr = PetscPrintf(appctx->comm,"Error vector\n");CHKERRQ(ierr);
    ierr = VecView(appctx->solution,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
  }

  return 0;
}

开发者ID:masa-ito，项目名称:PETScToPoisson，代码行数:75，代码来源:ex4.c

示例7: context

/*@C
   PetscDrawViewPortsCreate - Splits a window into smaller view ports. Each processor shares all the viewports.

   Collective on PetscDraw

   Input Parameters:
+  draw - the drawing context
-  nports - the number of ports

   Output Parameter:
.  ports - a PetscDrawViewPorts context (C structure)

   Options Database:
.  -draw_ports - display multiple fields in the same window with PetscDrawPorts instead of in seperate windows

   Level: advanced

   Concepts: drawing^in subset of window

.seealso: PetscDrawSplitViewPort(), PetscDrawSetViewPort(), PetscDrawViewPortsSet(), PetscDrawViewPortsDestroy()

@*/
PetscErrorCode  PetscDrawViewPortsCreate(PetscDraw draw,PetscInt nports,PetscDrawViewPorts **newports)
{
  PetscDrawViewPorts *ports;
  PetscInt           i,n;
  PetscBool          isnull;
  PetscMPIInt        rank;
  PetscReal          *xl,*xr,*yl,*yr,h;
  PetscErrorCode     ierr;

  PetscFunctionBegin;
  PetscValidHeaderSpecific(draw,PETSC_DRAW_CLASSID,1);
  if (nports < 1) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE, "Number of divisions must be positive: %d", nports);
  PetscValidPointer(newports,3);
  ierr = PetscDrawIsNull(draw,&isnull);CHKERRQ(ierr);
  if (isnull) {*newports = NULL; PetscFunctionReturn(0);}
  ierr = MPI_Comm_rank(PetscObjectComm((PetscObject)draw),&rank);CHKERRQ(ierr);

  ierr = PetscNew(&ports);CHKERRQ(ierr); *newports = ports;
  ports->draw = draw;
  ports->nports = nports;
  ierr = PetscObjectReference((PetscObject)draw);CHKERRQ(ierr);
  /* save previous drawport of window */
  ierr = PetscDrawGetViewPort(draw,&ports->port_xl,&ports->port_yl,&ports->port_xr,&ports->port_yr);CHKERRQ(ierr);

  n = (PetscInt)(.1 + PetscSqrtReal((PetscReal)nports));
  while (n*n < nports) n++;
  h = 1.0/n;

  ierr = PetscMalloc4(n*n,&xl,n*n,&xr,n*n,&yl,n*n,&yr);CHKERRQ(ierr);
  ports->xl = xl;
  ports->xr = xr;
  ports->yl = yl;
  ports->yr = yr;

  ierr = PetscDrawSetCoordinates(draw,0.0,0.0,1.0,1.0);CHKERRQ(ierr);
  ierr = PetscDrawCollectiveBegin(draw);CHKERRQ(ierr);
  for (i=0; i<n*n; i++) {
    xl[i] = (i % n)*h;
    xr[i] = xl[i] + h;
    yl[i] = (i / n)*h;
    yr[i] = yl[i] + h;

    if (!rank) {
      ierr = PetscDrawLine(draw,xl[i],yl[i],xl[i],yr[i],PETSC_DRAW_BLACK);CHKERRQ(ierr);
      ierr = PetscDrawLine(draw,xl[i],yr[i],xr[i],yr[i],PETSC_DRAW_BLACK);CHKERRQ(ierr);
      ierr = PetscDrawLine(draw,xr[i],yr[i],xr[i],yl[i],PETSC_DRAW_BLACK);CHKERRQ(ierr);
      ierr = PetscDrawLine(draw,xr[i],yl[i],xl[i],yl[i],PETSC_DRAW_BLACK);CHKERRQ(ierr);
    }

    xl[i] += .05*h;
    xr[i] -= .05*h;
    yl[i] += .05*h;
    yr[i] -= .05*h;
  }
  ierr = PetscDrawCollectiveEnd(draw);CHKERRQ(ierr);
  ierr = PetscDrawFlush(draw);CHKERRQ(ierr);
  PetscFunctionReturn(0);
}

开发者ID:firedrakeproject，项目名称:petsc，代码行数:80，代码来源:dviewp.c

示例8: FormInitialGuess

/*
   FormInitialGuess - Forms initial approximation.

   Input Parameters:
   user - user-defined application context
   X - vector

   Output Parameter:
   X - vector
 */
PetscErrorCode FormInitialGuess(AppCtx *user,Vec X)
{
  PetscInt       i,j,k,Mx,My,Mz,xs,ys,zs,xm,ym,zm;
  PetscErrorCode ierr;
  PetscReal      lambda,temp1,hx,hy,hz,tempk,tempj;
  PetscScalar    ***x;

  PetscFunctionBeginUser;
  ierr = DMDAGetInfo(user->da,PETSC_IGNORE,&Mx,&My,&Mz,PETSC_IGNORE,PETSC_IGNORE,PETSC_IGNORE,PETSC_IGNORE,PETSC_IGNORE,PETSC_IGNORE,PETSC_IGNORE,PETSC_IGNORE,PETSC_IGNORE);CHKERRQ(ierr);

  lambda = user->param;
  hx     = 1.0/(PetscReal)(Mx-1);
  hy     = 1.0/(PetscReal)(My-1);
  hz     = 1.0/(PetscReal)(Mz-1);
  temp1  = lambda/(lambda + 1.0);

  /*
     Get a pointer to vector data.
       - For default PETSc vectors, VecGetArray() returns a pointer to
         the data array.  Otherwise, the routine is implementation dependent.
       - You MUST call VecRestoreArray() when you no longer need access to
         the array.
  */
  ierr = DMDAVecGetArray(user->da,X,&x);CHKERRQ(ierr);

  /*
     Get local grid boundaries (for 3-dimensional DMDA):
       xs, ys, zs   - starting grid indices (no ghost points)
       xm, ym, zm   - widths of local grid (no ghost points)

  */
  ierr = DMDAGetCorners(user->da,&xs,&ys,&zs,&xm,&ym,&zm);CHKERRQ(ierr);

  /*
     Compute initial guess over the locally owned part of the grid
  */
  for (k=zs; k<zs+zm; k++) {
    tempk = (PetscReal)(PetscMin(k,Mz-k-1))*hz;
    for (j=ys; j<ys+ym; j++) {
      tempj = PetscMin((PetscReal)(PetscMin(j,My-j-1))*hy,tempk);
      for (i=xs; i<xs+xm; i++) {
        if (i == 0 || j == 0 || k == 0 || i == Mx-1 || j == My-1 || k == Mz-1) {
          /* boundary conditions are all zero Dirichlet */
          x[k][j][i] = 0.0;
        } else {
          x[k][j][i] = temp1*PetscSqrtReal(PetscMin((PetscReal)(PetscMin(i,Mx-i-1))*hx,tempj));
        }
      }
    }
  }

  /*
     Restore vector
  */
  ierr = DMDAVecRestoreArray(user->da,X,&x);CHKERRQ(ierr);
  PetscFunctionReturn(0);
}

开发者ID:mdmohsinali，项目名称:SGCT-Based-Fault-Tolerant-3D-SFI，代码行数:67，代码来源:ex14.c

示例9: step

/*
   Monitor - User-provided routine to monitor the solution computed at
   each timestep.  This example plots the solution and computes the
   error in two different norms.

   Input Parameters:
   ts     - the timestep context
   step   - the count of the current step (with 0 meaning the
             initial condition)
   time   - the current time
   u      - the solution at this timestep
   ctx    - the user-provided context for this monitoring routine.
            In this case we use the application context which contains
            information about the problem size, workspace and the exact
            solution.
*/
PetscErrorCode Monitor(TS ts,PetscInt step,PetscReal time,Vec u,void *ctx)
{
  AppCtx         *appctx = (AppCtx*) ctx;   /* user-defined application context */
  PetscErrorCode ierr;
  PetscReal      norm_2,norm_max;

  /*
     View a graph of the current iterate
  */
  ierr = VecView(u,appctx->viewer2);CHKERRQ(ierr);

  /*
     Compute the exact solution
  */
  ierr = ExactSolution(time,appctx->solution,appctx);CHKERRQ(ierr);

  /*
     Print debugging information if desired
  */
  if (appctx->debug) {
     printf("Computed solution vector\n");
     ierr = VecView(u,PETSC_VIEWER_STDOUT_SELF);CHKERRQ(ierr);
     printf("Exact solution vector\n");
     ierr = VecView(appctx->solution,PETSC_VIEWER_STDOUT_SELF);CHKERRQ(ierr);
  }

  /*
     Compute the 2-norm and max-norm of the error
  */
  ierr = VecAXPY(appctx->solution,-1.0,u);CHKERRQ(ierr);
  ierr = VecNorm(appctx->solution,NORM_2,&norm_2);CHKERRQ(ierr);
  norm_2 = PetscSqrtReal(appctx->h)*norm_2;
  ierr = VecNorm(appctx->solution,NORM_MAX,&norm_max);CHKERRQ(ierr);

  ierr = PetscPrintf(PETSC_COMM_WORLD,"Timestep %D: time = %G, 2-norm error = %G, max norm error = %G\n",
         step,time,norm_2,norm_max);CHKERRQ(ierr);
  appctx->norm_2   += norm_2;
  appctx->norm_max += norm_max;

  /*
     View a graph of the error
  */
  ierr = VecView(appctx->solution,appctx->viewer1);CHKERRQ(ierr);

  /*
     Print debugging information if desired
  */
  if (appctx->debug) {
     printf("Error vector\n");
     ierr = VecView(appctx->solution,PETSC_VIEWER_STDOUT_SELF);CHKERRQ(ierr);
  }

  return 0;
}

开发者ID:erdc-cm，项目名称:petsc-dev，代码行数:70，代码来源:ex5.c

示例10: KSPAGMRESLejaOrdering

PetscErrorCode KSPAGMRESLejaOrdering(PetscScalar *re, PetscScalar *im, PetscScalar *rre, PetscScalar *rim, PetscInt m)
{
  PetscInt       *spos;
  PetscScalar    *n_cmpl,temp;
  PetscErrorCode  ierr;
  PetscInt        i, pos, j;
  ierr = PetscMalloc(m*sizeof(PetscScalar), &n_cmpl);CHKERRQ(ierr);
  ierr = PetscMalloc(m*sizeof(PetscInt), &spos);CHKERRQ(ierr);

  PetscFunctionBegin;
  /* Check the proper order of complex conjugate pairs */
  j = 0;
  while (j  < m ) {
    if (im[j] != 0.0) {/* complex eigenvalue */
      if (im[j] < 0.0) { /* change the order */
        temp = im[j+1];
        im[j+1] = im[j];
        im[j] = temp;
      }
      j += 2;
    } else j++;
  }

  for (i = 0;i < m;i++)
    n_cmpl[i] = PetscSqrtReal(re[i]*re[i]+im[i]*im[i]);
  KSPAGMRESLejafmaxarray(n_cmpl, 0, m, &pos);
  j = 0;
  if (im[pos] >= 0.0) {
    rre[0] = re[pos];
    rim[0] = im[pos];
    j++;
    spos[0] = pos;
  }
  while (j < (m)) {
    if (im[pos] > 0) {
      rre[j] = re[pos+1];
      rim[j] = im[pos+1];
      spos[j] = pos + 1;
      j++;
    }
    KSPAGMRESLejaCfpdMax(re, im, spos, j, m, &pos);
    if (im[pos] < 0) pos--;

    if ((im[pos] >= 0) && (j < m)) {
      rre[j] = re[pos];
      rim[j] = im[pos];
      spos[j] = pos;
      j++;
    }
  }
  ierr = PetscFree(spos);CHKERRQ(ierr);
  ierr = PetscFree(n_cmpl);CHKERRQ(ierr);
  PetscFunctionReturn(0);
}

开发者ID:erdc-cm，项目名称:petsc-dev，代码行数:54，代码来源:agmresLeja.c

示例11: context

/*@C
   PetscDrawViewPortsCreate - Splits a window into smaller
       view ports. Each processor shares all the viewports.

   Collective on PetscDraw

   Input Parameters:
+  draw - the drawing context
-  nports - the number of ports

   Output Parameter:
.  ports - a PetscDrawViewPorts context (C structure)

   Level: advanced

   Concepts: drawing^in subset of window

.seealso: PetscDrawSplitViewPort(), PetscDrawSetViewPort(), PetscDrawViewPortsSet(), PetscDrawViewPortsDestroy()

@*/
PetscErrorCode  PetscDrawViewPortsCreate(PetscDraw draw,PetscInt nports,PetscDrawViewPorts **ports)
{
  PetscInt       i,n;
  PetscErrorCode ierr;
  PetscBool      isnull;
  PetscReal      *xl,*xr,*yl,*yr,h;

  PetscFunctionBegin;
  PetscValidHeaderSpecific(draw,PETSC_DRAW_CLASSID,1);
  PetscValidPointer(ports,3);
  ierr = PetscObjectTypeCompare((PetscObject)draw,PETSC_DRAW_NULL,&isnull);CHKERRQ(ierr);
  if (isnull) {
    *ports = NULL;
    PetscFunctionReturn(0);
  }

  ierr             = PetscNew(ports);CHKERRQ(ierr);
  (*ports)->draw   = draw;
  (*ports)->nports = nports;

  ierr = PetscObjectReference((PetscObject)draw);CHKERRQ(ierr);

  n = (PetscInt)(.1 + PetscSqrtReal((PetscReal)nports));
  while (n*n < nports) n++;

  ierr = PetscMalloc1(n*n,&xl);CHKERRQ(ierr);(*ports)->xl = xl;
  ierr = PetscMalloc1(n*n,&xr);CHKERRQ(ierr);(*ports)->xr = xr;
  ierr = PetscMalloc1(n*n,&yl);CHKERRQ(ierr);(*ports)->yl = yl;
  ierr = PetscMalloc1(n*n,&yr);CHKERRQ(ierr);(*ports)->yr = yr;

  h = 1.0/n;

  for (i=0; i<n*n; i++) {
    xl[i] = (i % n)*h;
    xr[i] = xl[i] + h;
    yl[i] = (i/n)*h;
    yr[i] = yl[i] + h;

    ierr = PetscDrawLine(draw,xl[i],yl[i],xl[i],yr[i],PETSC_DRAW_BLACK);CHKERRQ(ierr);
    ierr = PetscDrawLine(draw,xl[i],yr[i],xr[i],yr[i],PETSC_DRAW_BLACK);CHKERRQ(ierr);
    ierr = PetscDrawLine(draw,xr[i],yr[i],xr[i],yl[i],PETSC_DRAW_BLACK);CHKERRQ(ierr);
    ierr = PetscDrawLine(draw,xr[i],yl[i],xl[i],yl[i],PETSC_DRAW_BLACK);CHKERRQ(ierr);

    xl[i] += .1*h;
    xr[i] -= .1*h;
    yl[i] += .1*h;
    yr[i] -= .1*h;
  }
  /* save previous drawport of window */
  ierr = PetscDrawGetViewPort(draw,&(*ports)->port_xl,&(*ports)->port_yl,&(*ports)->port_xr,&(*ports)->port_yr);CHKERRQ(ierr);
  /* ierr = PetscDrawSynchronizedFlush(draw);CHKERRQ(ierr);*/  /* this causes flicker */
  PetscFunctionReturn(0);
}

开发者ID:ZJLi2013，项目名称:petsc，代码行数:73，代码来源:dviewp.c

示例12: SVDOrthogonalizeCGS

/*
  Custom CGS orthogonalization, preprocess after first orthogonalization
*/
static PetscErrorCode SVDOrthogonalizeCGS(BV V,PetscInt i,PetscScalar* h,PetscReal a,BVOrthogRefineType refine,PetscReal eta,PetscReal *norm)
{
  PetscErrorCode ierr;
  PetscReal      sum,onorm;
  PetscScalar    dot;
  PetscInt       j;

  PetscFunctionBegin;
  switch (refine) {
  case BV_ORTHOG_REFINE_NEVER:
    ierr = BVNormColumn(V,i,NORM_2,norm);CHKERRQ(ierr);
    break;
  case BV_ORTHOG_REFINE_ALWAYS:
    ierr = BVSetActiveColumns(V,0,i);CHKERRQ(ierr);
    ierr = BVDotColumn(V,i,h);CHKERRQ(ierr);
    ierr = BVMultColumn(V,-1.0,1.0,i,h);CHKERRQ(ierr);
    ierr = BVNormColumn(V,i,NORM_2,norm);CHKERRQ(ierr);
    break;
  case BV_ORTHOG_REFINE_IFNEEDED:
    dot = h[i];
    onorm = PetscSqrtReal(PetscRealPart(dot)) / a;
    sum = 0.0;
    for (j=0;j<i;j++) {
      sum += PetscRealPart(h[j] * PetscConj(h[j]));
    }
    *norm = PetscRealPart(dot)/(a*a) - sum;
    if (*norm>0.0) *norm = PetscSqrtReal(*norm);
    else {
      ierr = BVNormColumn(V,i,NORM_2,norm);CHKERRQ(ierr);
    }
    if (*norm < eta*onorm) {
      ierr = BVSetActiveColumns(V,0,i);CHKERRQ(ierr);
      ierr = BVDotColumn(V,i,h);CHKERRQ(ierr);
      ierr = BVMultColumn(V,-1.0,1.0,i,h);CHKERRQ(ierr);
      ierr = BVNormColumn(V,i,NORM_2,norm);CHKERRQ(ierr);
    }
    break;
  }
  PetscFunctionReturn(0);
}

开发者ID:OpenCMISS-Dependencies，项目名称:slepc，代码行数:43，代码来源:trlanczos.c

示例13: coordinate

/*@C
   DMDAGetLogicalCoordinate - Returns a the i,j,k logical coordinate for the closest mesh point to a x,y,z point in the coordinates of the DMDA

   Collective on DMDA

   Input Parameters:
+  da - the distributed array
-  x,y,z - the physical coordinates

   Output Parameters:
+   II, JJ, KK - the logical coordinate (-1 on processes that do not contain that point)
-   X, Y, Z, - (optional) the coordinates of the located grid point

   Level: advanced

   Notes:
   All processors that share the DMDA must call this with the same coordinate value

.keywords: distributed array, get, processor subset
@*/
PetscErrorCode  DMDAGetLogicalCoordinate(DM da,PetscScalar x,PetscScalar y,PetscScalar z,PetscInt *II,PetscInt *JJ,PetscInt *KK,PetscScalar *X,PetscScalar *Y,PetscScalar *Z)
{
  DM_DA          *dd = (DM_DA*)da->data;
  PetscErrorCode ierr;
  Vec            coors;
  DM             dacoors;
  DMDACoor2d     **c;
  PetscInt       i,j,xs,xm,ys,ym;
  PetscReal      d,D = PETSC_MAX_REAL,Dv;
  PetscMPIInt    rank,root;

  PetscFunctionBegin;
  if (dd->dim == 1) SETERRQ(PetscObjectComm((PetscObject)da),PETSC_ERR_SUP,"Cannot get point from 1d DMDA");
  if (dd->dim == 3) SETERRQ(PetscObjectComm((PetscObject)da),PETSC_ERR_SUP,"Cannot get point from 3d DMDA");

  *II = -1;
  *JJ = -1;

  ierr = DMGetCoordinateDM(da,&dacoors);CHKERRQ(ierr);
  ierr = DMDAGetCorners(dacoors,&xs,&ys,NULL,&xm,&ym,NULL);CHKERRQ(ierr);
  ierr = DMGetCoordinates(da,&coors);CHKERRQ(ierr);
  ierr = DMDAVecGetArray(dacoors,coors,&c);CHKERRQ(ierr);
  for (j=ys; j<ys+ym; j++) {
    for (i=xs; i<xs+xm; i++) {
      d = PetscSqrtReal(PetscRealPart( (c[j][i].x - x)*(c[j][i].x - x) + (c[j][i].y - y)*(c[j][i].y - y) ));
      if (d < D) {
        D   = d;
        *II = i;
        *JJ = j;
      }
    }
  }
  ierr = MPI_Allreduce(&D,&Dv,1,MPIU_REAL,MPI_MIN,PetscObjectComm((PetscObject)da));CHKERRQ(ierr);
  if (D != Dv) {
    *II  = -1;
    *JJ  = -1;
    rank = 0;
  } else {
    *X = c[*JJ][*II].x;
    *Y = c[*JJ][*II].y;
    ierr = MPI_Comm_rank(PetscObjectComm((PetscObject)da),&rank);CHKERRQ(ierr);
    rank++;
  }
  ierr = MPI_Allreduce(&rank,&root,1,MPI_INT,MPI_SUM,PetscObjectComm((PetscObject)da));CHKERRQ(ierr);
  root--;
  ierr = MPI_Bcast(X,1,MPIU_SCALAR,root,PetscObjectComm((PetscObject)da));CHKERRQ(ierr);
  ierr = MPI_Bcast(Y,1,MPIU_SCALAR,root,PetscObjectComm((PetscObject)da));CHKERRQ(ierr);
  ierr = DMDAVecRestoreArray(dacoors,coors,&c);CHKERRQ(ierr);
  PetscFunctionReturn(0);
}

开发者ID:feelpp，项目名称:debian-petsc，代码行数:70，代码来源:dasub.c

示例14: SNESNGMRESSelectRestart_Private

PetscErrorCode SNESNGMRESSelectRestart_Private(SNES snes,PetscInt l,PetscReal fAnorm,PetscReal dnorm,PetscReal fminnorm,PetscReal dminnorm,PetscBool *selectRestart)
{
  SNES_NGMRES    *ngmres = (SNES_NGMRES*)snes->data;
  PetscErrorCode ierr;

  PetscFunctionBegin;
  *selectRestart = PETSC_FALSE;
  /* difference stagnation restart */
  if ((ngmres->epsilonB*dnorm > dminnorm) && (PetscSqrtReal(fAnorm) > ngmres->deltaB*PetscSqrtReal(fminnorm)) && l > 0) {
    if (ngmres->monitor) {
      ierr = PetscViewerASCIIPrintf(ngmres->monitor,"difference restart: %e > %e\n",ngmres->epsilonB*dnorm,dminnorm);CHKERRQ(ierr);
    }
    *selectRestart = PETSC_TRUE;
  }
  /* residual stagnation restart */
  if (PetscSqrtReal(fAnorm) > ngmres->gammaC*PetscSqrtReal(fminnorm)) {
    if (ngmres->monitor) {
      ierr = PetscViewerASCIIPrintf(ngmres->monitor,"residual restart: %e > %e\n",PetscSqrtReal(fAnorm),ngmres->gammaC*PetscSqrtReal(fminnorm));CHKERRQ(ierr);
    }
    *selectRestart = PETSC_TRUE;
  }
  PetscFunctionReturn(0);
}

开发者ID:hansec，项目名称:petsc，代码行数:23，代码来源:ngmresfunc.c

示例15: VecNorm_MPI

PetscErrorCode VecNorm_MPI(Vec xin,NormType type,PetscReal *z)
{
  PetscReal         sum,work = 0.0;
  const PetscScalar *xx;
  PetscErrorCode    ierr;
  PetscInt          n   = xin->map->n;
  PetscBLASInt      one = 1,bn;

  PetscFunctionBegin;
  ierr = PetscBLASIntCast(n,&bn);CHKERRQ(ierr);
  if (type == NORM_2 || type == NORM_FROBENIUS) {
    ierr = VecGetArrayRead(xin,&xx);CHKERRQ(ierr);
    work = PetscRealPart(BLASdot_(&bn,xx,&one,xx,&one));
    ierr = VecRestoreArrayRead(xin,&xx);CHKERRQ(ierr);
    ierr = MPIU_Allreduce(&work,&sum,1,MPIU_REAL,MPIU_SUM,PetscObjectComm((PetscObject)xin));CHKERRQ(ierr);
    *z   = PetscSqrtReal(sum);
    ierr = PetscLogFlops(2.0*xin->map->n);CHKERRQ(ierr);
  } else if (type == NORM_1) {
    /* Find the local part */
    ierr = VecNorm_Seq(xin,NORM_1,&work);CHKERRQ(ierr);
    /* Find the global max */
    ierr = MPIU_Allreduce(&work,z,1,MPIU_REAL,MPIU_SUM,PetscObjectComm((PetscObject)xin));CHKERRQ(ierr);
  } else if (type == NORM_INFINITY) {
    /* Find the local max */
    ierr = VecNorm_Seq(xin,NORM_INFINITY,&work);CHKERRQ(ierr);
    /* Find the global max */
    ierr = MPIU_Allreduce(&work,z,1,MPIU_REAL,MPIU_MAX,PetscObjectComm((PetscObject)xin));CHKERRQ(ierr);
  } else if (type == NORM_1_AND_2) {
    PetscReal temp[2];
    ierr = VecNorm_Seq(xin,NORM_1,temp);CHKERRQ(ierr);
    ierr = VecNorm_Seq(xin,NORM_2,temp+1);CHKERRQ(ierr);
    temp[1] = temp[1]*temp[1];
    ierr = MPIU_Allreduce(temp,z,2,MPIU_REAL,MPIU_SUM,PetscObjectComm((PetscObject)xin));CHKERRQ(ierr);
    z[1] = PetscSqrtReal(z[1]);
  }
  PetscFunctionReturn(0);
}

开发者ID:tom-klotz，项目名称:petsc，代码行数:37，代码来源:pvec2.c

示例16: sqrt

/*@
   SVDComputeRelativeError - Computes the relative error bound associated
   with the i-th singular triplet.

   Collective on SVD

   Input Parameter:
+  svd - the singular value solver context
-  i   - the solution index

   Output Parameter:
.  error - the relative error bound, computed as sqrt(n1^2+n2^2)/sigma
   where n1 = ||A*v-sigma*u||_2 , n2 = ||A^T*u-sigma*v||_2 , sigma is the singular value,
   u and v are the left and right singular vectors.
   If sigma is too small the relative error is computed as sqrt(n1^2+n2^2).

   Level: beginner

.seealso: SVDSolve(), SVDComputeResidualNorms()
@*/
PetscErrorCode SVDComputeRelativeError(SVD svd,PetscInt i,PetscReal *error)
{
  PetscErrorCode ierr;
  PetscReal      sigma,norm1,norm2;

  PetscFunctionBegin;
  PetscValidHeaderSpecific(svd,SVD_CLASSID,1);
  PetscValidLogicalCollectiveInt(svd,i,2);
  PetscValidPointer(error,3);
  ierr = SVDGetSingularTriplet(svd,i,&sigma,NULL,NULL);CHKERRQ(ierr);
  ierr = SVDComputeResidualNorms(svd,i,&norm1,&norm2);CHKERRQ(ierr);
  *error = PetscSqrtReal(norm1*norm1+norm2*norm2);
  if (sigma>*error) *error /= sigma;
  PetscFunctionReturn(0);
}

开发者ID:OpenCMISS-Dependencies，项目名称:slepc，代码行数:35，代码来源:svdsolve.c

示例17: FormInitialSolution

PetscErrorCode FormInitialSolution(DM da,Vec U)
{
  PetscErrorCode ierr;
  PetscInt       i,j,xs,ys,xm,ym,Mx,My;
  PetscScalar    ***u;
  PetscReal      hx,hy,x,y,r;

  PetscFunctionBeginUser;
  ierr = DMDAGetInfo(da,PETSC_IGNORE,&Mx,&My,PETSC_IGNORE,PETSC_IGNORE,PETSC_IGNORE,
                     PETSC_IGNORE,PETSC_IGNORE,PETSC_IGNORE,PETSC_IGNORE,PETSC_IGNORE,PETSC_IGNORE,PETSC_IGNORE);

  hx = 1.0/(PetscReal)(Mx-1);
  hy = 1.0/(PetscReal)(My-1);

  /*
     Get pointers to vector data
  */
  ierr = DMDAVecGetArrayDOF(da,U,&u);CHKERRQ(ierr);

  /*
     Get local grid boundaries
  */
  ierr = DMDAGetCorners(da,&xs,&ys,NULL,&xm,&ym,NULL);CHKERRQ(ierr);

  /*
     Compute function over the locally owned part of the grid
  */
  for (j=ys; j<ys+ym; j++) {
    y = j*hy;
    for (i=xs; i<xs+xm; i++) {
      x = i*hx;
      r = PetscSqrtReal((x-.5)*(x-.5) + (y-.5)*(y-.5));
      if (r < .125) {
        u[j][i][0] = PetscExpReal(-30.0*r*r*r);
        u[j][i][1] = 0.0;
      } else {
        u[j][i][0] = 0.0;
        u[j][i][1] = 0.0;
      }
    }
  }

  /*
     Restore vectors
  */
  ierr = DMDAVecRestoreArrayDOF(da,U,&u);CHKERRQ(ierr);
  PetscFunctionReturn(0);
}

开发者ID:plguhur，项目名称:petsc，代码行数:48，代码来源:ex12.c

示例18: DMDASplitComm2d

PetscErrorCode  DMDASplitComm2d(MPI_Comm comm,PetscInt M,PetscInt N,PetscInt sw,MPI_Comm *outcomm)
{
  PetscErrorCode ierr;
  PetscInt       m,n = 0,x = 0,y = 0;
  PetscMPIInt    size,csize,rank;

  PetscFunctionBegin;
  ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
  ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);

  csize = 4*size;
  do {
    if (csize % 4) SETERRQ4(PETSC_COMM_SELF,PETSC_ERR_ARG_INCOMP,"Cannot split communicator of size %d tried %d %D %D",size,csize,x,y);
    csize = csize/4;

    m = (PetscInt)(0.5 + PetscSqrtReal(((PetscReal)M)*((PetscReal)csize)/((PetscReal)N)));
    if (!m) m = 1;
    while (m > 0) {
      n = csize/m;
      if (m*n == csize) break;
      m--;
    }
    if (M > N && m < n) {PetscInt _m = m; m = n; n = _m;}

    x = M/m + ((M % m) > ((csize-1) % m));
    y = (N + (csize-1)/m)/n;
  } while ((x < 4 || y < 4) && csize > 1);
  if (size != csize) {
    MPI_Group   entire_group,sub_group;
    PetscMPIInt i,*groupies;

    ierr = MPI_Comm_group(comm,&entire_group);CHKERRQ(ierr);
    ierr = PetscMalloc1(csize,&groupies);CHKERRQ(ierr);
    for (i=0; i<csize; i++) {
      groupies[i] = (rank/csize)*csize + i;
    }
    ierr = MPI_Group_incl(entire_group,csize,groupies,&sub_group);CHKERRQ(ierr);
    ierr = PetscFree(groupies);CHKERRQ(ierr);
    ierr = MPI_Comm_create(comm,sub_group,outcomm);CHKERRQ(ierr);
    ierr = MPI_Group_free(&entire_group);CHKERRQ(ierr);
    ierr = MPI_Group_free(&sub_group);CHKERRQ(ierr);
    ierr = PetscInfo1(0,"DMDASplitComm2d:Creating redundant coarse problems of size %d\n",csize);CHKERRQ(ierr);
  } else {
    *outcomm = comm;
  }
  PetscFunctionReturn(0);
}

开发者ID:PeiLiu90，项目名称:petsc，代码行数:47，代码来源:da2.c

示例19: reorthogonalization

/*
   EPSDelayedArnoldi1 - This function is similar to EPSDelayedArnoldi,
   but without reorthogonalization (only delayed normalization).
*/
PetscErrorCode EPSDelayedArnoldi1(EPS eps,PetscScalar *H,PetscInt ldh,Vec *V,PetscInt k,PetscInt *M,Vec f,PetscReal *beta,PetscBool *breakdown)
{
  PetscErrorCode ierr;
  PetscInt       i,j,m=*M;
  PetscScalar    dot;
  PetscReal      norm=0.0;

  PetscFunctionBegin;
  for (j=k;j<m;j++) {
    ierr = STApply(eps->st,V[j],f);CHKERRQ(ierr);
    ierr = IPOrthogonalize(eps->ip,0,NULL,eps->nds,NULL,eps->defl,f,NULL,NULL,NULL);CHKERRQ(ierr);

    ierr = IPMInnerProductBegin(eps->ip,f,j+1,V,H+ldh*j);CHKERRQ(ierr);
    if (j>k) {
      ierr = IPInnerProductBegin(eps->ip,V[j],V[j],&dot);CHKERRQ(ierr);
    }

    ierr = IPMInnerProductEnd(eps->ip,f,j+1,V,H+ldh*j);CHKERRQ(ierr);
    if (j>k) {
      ierr = IPInnerProductEnd(eps->ip,V[j],V[j],&dot);CHKERRQ(ierr);
    }

    if (j>k) {
      norm = PetscSqrtReal(PetscRealPart(dot));
      ierr = VecScale(V[j],1.0/norm);CHKERRQ(ierr);
      H[ldh*(j-1)+j] = norm;

      for (i=0;i<j;i++)
        H[ldh*j+i] = H[ldh*j+i]/norm;
      H[ldh*j+j] = H[ldh*j+j]/dot;
      ierr = VecScale(f,1.0/norm);CHKERRQ(ierr);
    }

    ierr = SlepcVecMAXPBY(f,1.0,-1.0,j+1,H+ldh*j,V);CHKERRQ(ierr);

    if (j<m-1) {
      ierr = VecCopy(f,V[j+1]);CHKERRQ(ierr);
    }
  }

  ierr = IPNorm(eps->ip,f,beta);CHKERRQ(ierr);
  ierr = VecScale(f,1.0 / *beta);CHKERRQ(ierr);
  *breakdown = PETSC_FALSE;
  PetscFunctionReturn(0);
}

开发者ID:OpenCMISS-Dependencies，项目名称:slepc，代码行数:49，代码来源:arnoldi.c

示例20: stdNormalArray

PetscErrorCode stdNormalArray(PetscReal *eps, PetscInt numdim, PetscRandom ran)
{
  PetscInt       i;
  PetscScalar    u1,u2;
  PetscReal      t;
  PetscErrorCode ierr;

  PetscFunctionBegin;
  for (i=0; i<numdim; i+=2) {
    ierr = PetscRandomGetValue(ran,&u1);CHKERRQ(ierr);
    ierr = PetscRandomGetValue(ran,&u2);CHKERRQ(ierr);

    t        = PetscSqrtReal(-2*PetscLogReal(PetscRealPart(u1)));
    eps[i]   = t * PetscCosReal(2*PETSC_PI*PetscRealPart(u2));
    eps[i+1] = t * PetscSinReal(2*PETSC_PI*PetscRealPart(u2));
  }
  PetscFunctionReturn(0);
}

开发者ID:firedrakeproject，项目名称:petsc，代码行数:18，代码来源:ex2.c

注：本文中的PetscSqrtReal函数示例由纯净天空整理自Github/MSDocs等源码及文档管理平台，相关代码片段筛选自各路编程大神贡献的开源项目，源码版权归原作者所有，传播和使用请参考对应项目的License；未经允许，请勿转载。

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C++ PetscSqrtReal函数代码示例

示例1: step

示例2: FormInitialGuess

示例3: StokesCalcError

示例4: interval

示例5: FormInitialGuess

示例6: step

示例7: context

示例8: FormInitialGuess

示例9: step

示例10: KSPAGMRESLejaOrdering

示例11: context

示例12: SVDOrthogonalizeCGS

示例13: coordinate

示例14: SNESNGMRESSelectRestart_Private

示例15: VecNorm_MPI

示例16: sqrt

示例17: FormInitialSolution

示例18: DMDASplitComm2d

示例19: reorthogonalization

示例20: stdNormalArray

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