[petsc-users] *****SPAM*****Create vector with evenly spaced values

[Barry Smith]

   Better to just use VecGetArray() to access the Vector’s day and not allocate new space with the PetscMalloc()


On Aug 29, 2014, at 8:55 AM, Florian Lindner <mailinglists at xgm.de> wrote:

> Am 27.08.2014 14:12, schrieb Florian Lindner:
>> Hello,
>> is there a way to create a vector with evenly spaced values in an
>> interval, like the numpy.arange function?
>> http://docs.scipy.org/doc/numpy/reference/generated/numpy.arange.html
>> or the linspace function?
> 
> Ok, I gave it as try. Do I need the VecAssembly the vector?
> 
> 
> void arange(size_t start, size_t stop)
>    {
>      // given a vector of appropriate size
>      PetscScalar ierr;
>      PetscScalar *a;
>      ierr = PetscMalloc(sizeof(PetscScalar) * (stop-start), &a); CHKERRV(ierr);
>      size_t pos = 0;
>      for (size_t i = start; i < stop; i++) {
>        a[pos] = i;
>        pos++;
>      }
>      cout << "Array filled." << endl;
>      VecReplaceArray(vector, a);
>      // VecAssemblyBegin(vector); VecAssemblyEnd(vector);  Do I need that?
>    }
> 
> Any comments?
> 
> Thanks,
> Florian