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: */

 11: static char help[] = "Test exponential function.\n\n";

 13: #include <slepcfn.h>

 15: int main(int argc,char **argv)
 16: {
 17:   FN             fn,fncopy;
 18:   PetscScalar    x,y,yp,tau,eta,alpha,beta;
 19:   char           strx[50],str[50];

 21:   PetscFunctionBeginUser;
 22:   PetscCall(SlepcInitialize(&argc,&argv,(char*)0,help));
 23:   PetscCall(FNCreate(PETSC_COMM_WORLD,&fn));
 24:   PetscCall(FNSetFromOptions(fn));

 26:   /* plain exponential exp(x) */
 27:   PetscCall(FNSetType(fn,FNEXP));
 28:   PetscCall(FNView(fn,NULL));
 29:   x = 2.2;
 30:   PetscCall(SlepcSNPrintfScalar(strx,sizeof(strx),x,PETSC_FALSE));
 31:   PetscCall(FNEvaluateFunction(fn,x,&y));
 32:   PetscCall(FNEvaluateDerivative(fn,x,&yp));
 33:   PetscCall(SlepcSNPrintfScalar(str,sizeof(str),y,PETSC_FALSE));
 34:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"  f(%s)=%s\n",strx,str));
 35:   PetscCall(SlepcSNPrintfScalar(str,sizeof(str),yp,PETSC_FALSE));
 36:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"  f'(%s)=%s\n",strx,str));

 38:   /* exponential with scaling factors eta*exp(tau*x) */
 39:   PetscCall(FNSetType(fn,FNEXP));
 40:   tau = -0.2;
 41:   eta = 1.3;
 42:   PetscCall(FNSetScale(fn,tau,eta));
 43:   PetscCall(FNView(fn,NULL));
 44:   x = 2.2;
 45:   PetscCall(SlepcSNPrintfScalar(strx,sizeof(strx),x,PETSC_FALSE));
 46:   PetscCall(FNEvaluateFunction(fn,x,&y));
 47:   PetscCall(FNEvaluateDerivative(fn,x,&yp));
 48:   PetscCall(SlepcSNPrintfScalar(str,sizeof(str),y,PETSC_FALSE));
 49:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"  f(%s)=%s\n",strx,str));
 50:   PetscCall(SlepcSNPrintfScalar(str,sizeof(str),yp,PETSC_FALSE));
 51:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"  f'(%s)=%s\n",strx,str));

 53:   /* test FNDuplicate */
 54:   PetscCall(FNDuplicate(fn,PetscObjectComm((PetscObject)fn),&fncopy));

 56:   /* test FNGetScale */
 57:   PetscCall(FNGetScale(fncopy,&alpha,&beta));
 58:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"Parameters:\n - alpha: "));
 59:   PetscCall(SlepcSNPrintfScalar(str,sizeof(str),alpha,PETSC_FALSE));
 60:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"%s ",str));
 61:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"\n - beta: "));
 62:   PetscCall(SlepcSNPrintfScalar(str,sizeof(str),beta,PETSC_FALSE));
 63:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"%s ",str));
 64:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"\n"));

 66:   PetscCall(FNDestroy(&fn));
 67:   PetscCall(FNDestroy(&fncopy));
 68:   PetscCall(SlepcFinalize());
 69:   return 0;
 70: }

 72: /*TEST

 74:    test:
 75:       suffix: 1
 76:       nsize: 1
 77:       filter: grep -v "computing matrix functions"

 79: TEST*/