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 DSGNHEP with upper quasi-triangular matrix pair.\n\n";

 13: #include <slepcds.h>

 15: int main(int argc,char **argv)
 16: {
 17:   DS             ds;
 18:   PetscScalar    *A,*B,*X;
 19:   PetscReal      rnorm,aux;
 20:   PetscInt       i,j,n=10,ld;
 21:   PetscViewer    viewer;
 22:   PetscBool      verbose;

 24:   PetscFunctionBeginUser;
 25:   PetscCall(SlepcInitialize(&argc,&argv,NULL,help));
 26:   PetscCall(PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL));
 27:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"Solve a Dense System of type GNHEP - dimension %" PetscInt_FMT ".\n",n));
 28:   PetscCall(PetscOptionsHasName(NULL,NULL,"-verbose",&verbose));

 30:   /* Create DS object */
 31:   PetscCall(DSCreate(PETSC_COMM_WORLD,&ds));
 32:   PetscCall(DSSetType(ds,DSGNHEP));
 33:   PetscCall(DSSetFromOptions(ds));
 34:   ld = n+2;  /* test leading dimension larger than n */
 35:   PetscCall(DSAllocate(ds,ld));
 36:   PetscCall(DSSetDimensions(ds,n,0,0));

 38:   /* Set up viewer */
 39:   PetscCall(PetscViewerASCIIGetStdout(PETSC_COMM_WORLD,&viewer));
 40:   PetscCall(PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_INFO_DETAIL));
 41:   PetscCall(DSView(ds,viewer));
 42:   PetscCall(PetscViewerPopFormat(viewer));
 43:   if (verbose) PetscCall(PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_MATLAB));

 45:   /* Fill A,B with upper quasi-triangular matrices */
 46:   PetscCall(DSGetArray(ds,DS_MAT_A,&A));
 47:   PetscCall(DSGetArray(ds,DS_MAT_B,&B));
 48:   PetscCall(PetscArrayzero(A,ld*n));
 49:   for (i=0;i<n;i++) A[i+i*ld]=2.0;
 50:   for (j=1;j<3;j++) {
 51:     for (i=0;i<n-j;i++) A[i+(i+j)*ld]=0.001;
 52:   }
 53:   PetscCall(PetscArrayzero(B,ld*n));
 54:   for (i=0;i<n;i++) B[i+i*ld]=1.0;
 55:   B[1+0*ld]=B[0+1*ld]=PETSC_MACHINE_EPSILON;
 56:   for (i=1;i<n;i+=3) {
 57:     A[i+(i-1)*ld]=-A[(i-1)+i*ld];
 58:   }
 59:   PetscCall(DSRestoreArray(ds,DS_MAT_A,&A));
 60:   PetscCall(DSRestoreArray(ds,DS_MAT_B,&B));
 61:   PetscCall(DSSetState(ds,DS_STATE_INTERMEDIATE));

 63:   if (verbose) {
 64:     PetscCall(PetscPrintf(PETSC_COMM_WORLD,"Initial - - - - - - - - -\n"));
 65:     PetscCall(DSView(ds,viewer));
 66:   }

 68:   /* Eigenvectors */
 69:   j = 0;
 70:   PetscCall(DSVectors(ds,DS_MAT_X,&j,&rnorm));  /* first eigenvector */
 71:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"Value of rnorm for 2nd vector = %.3f\n",(double)rnorm));
 72:   PetscCall(DSVectors(ds,DS_MAT_X,NULL,NULL));  /* all eigenvectors */
 73:   j = 0;
 74:   rnorm = 0.0;
 75:   PetscCall(DSGetArray(ds,DS_MAT_X,&X));
 76:   for (i=0;i<n;i++) {
 77: #if defined(PETSC_USE_COMPLEX)
 78:     aux = PetscAbsScalar(X[i+j*ld]);
 79: #else
 80:     aux = SlepcAbsEigenvalue(X[i+j*ld],X[i+(j+1)*ld]);
 81: #endif
 82:     rnorm += aux*aux;
 83:   }
 84:   PetscCall(DSRestoreArray(ds,DS_MAT_X,&X));
 85:   rnorm = PetscSqrtReal(rnorm);
 86:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"Norm of 1st columns = %.3f\n",(double)rnorm));
 87:   if (verbose) {
 88:     PetscCall(PetscPrintf(PETSC_COMM_WORLD,"After vectors - - - - - - - - -\n"));
 89:     PetscCall(DSView(ds,viewer));
 90:   }

 92:   PetscCall(DSDestroy(&ds));
 93:   PetscCall(SlepcFinalize());
 94:   return 0;
 95: }

 97: /*TEST

 99:    test:
100:       suffix: 1
101:       filter: sed -e "s/-0\./0./"

103: TEST*/