Date: 2017-05-17T08:24:58+00:00

Actual source code: fnlog.c
slepc-3.7.4 2017-05-17
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      1: /*
      2:    Logarithm function  log(x)

      4:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      5:    SLEPc - Scalable Library for Eigenvalue Problem Computations
      6:    Copyright (c) 2002-2016, Universitat Politecnica de Valencia, Spain

      8:    This file is part of SLEPc.

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

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

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

     24: #include <slepc/private/fnimpl.h>      /*I "slepcfn.h" I*/

     28: PetscErrorCode FNEvaluateFunction_Log(FN fn,PetscScalar x,PetscScalar *y)
     29: {
     31:   *y = PetscLogScalar(x);
     32:   return(0);
     33: }

     37: PetscErrorCode FNEvaluateDerivative_Log(FN fn,PetscScalar x,PetscScalar *y)
     38: {
     40:   if (x==0.0) SETERRQ(PETSC_COMM_SELF,1,"Derivative not defined in the requested value");
     41:   *y = 1.0/x;
     42:   return(0);
     43: }

     47: PetscErrorCode FNView_Log(FN fn,PetscViewer viewer)
     48: {
     50:   PetscBool      isascii;
     51:   char           str[50];

     54:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&isascii);
     55:   if (isascii) {
     56:     if (fn->beta==(PetscScalar)1.0) {
     57:       if (fn->alpha==(PetscScalar)1.0) {
     58:         PetscViewerASCIIPrintf(viewer,"  Logarithm: log(x)\n");
     59:       } else {
     60:         SlepcSNPrintfScalar(str,50,fn->alpha,PETSC_TRUE);
     61:         PetscViewerASCIIPrintf(viewer,"  Logarithm: log(%s*x)\n",str);
     62:       }
     63:     } else {
     64:       SlepcSNPrintfScalar(str,50,fn->beta,PETSC_TRUE);
     65:       if (fn->alpha==(PetscScalar)1.0) {
     66:         PetscViewerASCIIPrintf(viewer,"  Logarithm: %s*log(x)\n",str);
     67:       } else {
     68:         PetscViewerASCIIPrintf(viewer,"  Logarithm: %s",str);
     69:         PetscViewerASCIIUseTabs(viewer,PETSC_FALSE);
     70:         SlepcSNPrintfScalar(str,50,fn->alpha,PETSC_TRUE);
     71:         PetscViewerASCIIPrintf(viewer,"*log(%s*x)\n",str);
     72:         PetscViewerASCIIUseTabs(viewer,PETSC_TRUE);
     73:       }
     74:     }
     75:   }
     76:   return(0);
     77: }

     81: PETSC_EXTERN PetscErrorCode FNCreate_Log(FN fn)
     82: {
     84:   fn->ops->evaluatefunction    = FNEvaluateFunction_Log;
     85:   fn->ops->evaluatederivative  = FNEvaluateDerivative_Log;
     86:   fn->ops->view                = FNView_Log;
     87:   return(0);
     88: }