#include "slepcrg.h" PetscErrorCode RGRingSetParameters(RG rg,PetscScalar center,PetscReal radius,PetscReal vscale,PetscReal start_ang,PetscReal end_ang,PetscReal width)Logically Collective
| rg | - the region context | |
| center | - center of the ellipse | |
| radius | - radius of the ellipse | |
| vscale | - vertical scale of the ellipse | |
| start_ang | - the right-hand side angle | |
| end_ang | - the left-hand side angle | |
| width | - width of the ring |
| -rg_ring_center | - Sets the center | |
| -rg_ring_radius | - Sets the radius | |
| -rg_ring_vscale | - Sets the vertical scale | |
| -rg_ring_startangle | - Sets the right-hand side angle | |
| -rg_ring_endangle | - Sets the left-hand side angle | |
| -rg_ring_width | - Sets the width of the ring |
The start and end angles are expressed as a fraction of the circumference. The allowed range is [0..1], with 0 corresponding to 0 radians, 0.25 to pi/2 radians, and so on. It is allowed to have startangle>endangle, in which case the ring region crosses over the zero angle.
In the case of complex scalars, a complex center can be provided in the command line with [+/-][realnumber][+/-]realnumberi with no spaces, e.g. -rg_ring_center 1.0+2.0i
When PETSc is built with real scalars, the center is restricted to a real value, and the start and end angles must be such that the region is symmetric with respect to the real axis.
For all arguments except center, you can use PETSC_CURRENT to keep the current value, and PETSC_DETERMINE to set them to a default value (1 for radius, vscale, end_ang, 0 for start_and, and 0.1 for width).