[petsc-users] Newbie question : complex number with MatView ?

[Barry Smith]

  Yes, but you do not need to. You can say

  PetscComplex x = 1.0;


> On Feb 20, 2017, at 6:20 PM, lixin chu <lixin_chu at yahoo.com> wrote:
> 
> Yes, I compiled with complex data type. 
> 
> Is setting imaginary part 0 ok ? Like this:
> 
> 1.0 ÷ 0.0 * PETSC_i 
> 
> 
> Sent from Yahoo Mail on Android
> 
> On Tue, 21 Feb 2017 at 0:02, Barry Smith
> <bsmith at mcs.anl.gov> wrote:
> 
>   PETSc must be configured with --with-scalar-type=complex to use complex numbers. Then all PETSc vectors/matrices contain complex numbers. You cannot mix PETSc objects with real numbers and PETSc objects with complex numbers in the same program.
> 
> 
>   Barry
> 
> > On Feb 20, 2017, at 6:27 AM, lixin chu <lixin_chu at yahoo.com> wrote:
> > 
> > Hello,
> > Some questions wrt complex number - I have compiled PETSc with complex data type, but having problems of setting/getting the values:
> > 
> > - MatView does not seem to print complex number ? 
> > 
> > - Does MATSEQAIJ support row major SetValues for complex number ? I have tested real number, it is ok. I can not get the right values with MatGetRow. Still troubleshooting if it is my program problem...
> > 
> > This is how I set the matrix:
> > 
> >  PetscComplex *buffer; // this is the column data buffer, malloc'ed
> > 
> >  // setting the values
> >  buffer [i] = double1 + double2 * PETSC_i;
> > 
> > Then call MatSetValues, passing buffer. 
> >   
> > The program is ok for real numbers, btw.
> > 
> > 
> > I use a 5x5 matrix, when setting buffer for column 2, I can see these are the data passed to MatSetValues (row, col):
> > (0, 2)  1 + 0
> > (1, 2)  1 + 0
> > (3, 2)  -1 + 0
> > 
> > 
> > But MatGetRow return:
> > (0, 2)  1. + 1. i
> > (1, 2)  0. + 1. i
> > (3, 2)  1. + 0. i
> > 
> > (I have used MatRestoreRow after MatGetRow).
> > 
> > for ( i = 0; i < rows; i++ ) {
> >     MatGetRow ( Z, i, ¤t_doubles, &col_index, &complex_buffer );
> >     if ( current_doubles > 0 ) {
> >         for ( j = 0; j < current_doubles; j++ ) {
> >             PetscPrintf ( PETSC_COMM_WORLD, "(%d, %d)  %g + %g i\n", i, col_index[j], PetscRealPart(complex_buffer[j]), PetscImaginaryPart (complex_buffer[j]) );
> >         }
> >     }
> >     MatRestoreRow( Z, i, ¤t_doubles, &col_index, &complex_buffer );
> > }
> > 
> >  
> > thanks !
> > LX