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Diffstat (limited to 'Source/Particles/ShapeFactors.H')
| -rw-r--r-- | Source/Particles/ShapeFactors.H | 117 |
1 files changed, 117 insertions, 0 deletions
diff --git a/Source/Particles/ShapeFactors.H b/Source/Particles/ShapeFactors.H new file mode 100644 index 000000000..9d185714a --- /dev/null +++ b/Source/Particles/ShapeFactors.H @@ -0,0 +1,117 @@ +#ifndef SHAPEFACTORS_H_ +#define SHAPEFACTORS_H_ + +// Compute shape factor and return index of leftmost cell where +// particle writes. +// Specialized templates are defined below for orders 0 to 3. +template <int depos_order> +AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE +int compute_shape_factor(amrex::Real* const sx, amrex::Real xint) +{ + return 0; +}; + +// Compute shape factor for order 0. +template <> +AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE +int compute_shape_factor <0> (amrex::Real* const sx, amrex::Real xmid){ + const int j = (int) (xmid+0.5); + sx[0] = 1.0; + return j; +} + +// Compute shape factor for order 1. +template <> +AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE +int compute_shape_factor <1> (amrex::Real* const sx, amrex::Real xmid){ + const int j = (int) xmid; + const amrex::Real xint = xmid-j; + sx[0] = 1.0 - xint; + sx[1] = xint; + return j; +} + +// Compute shape factor for order 2. +template <> +AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE +int compute_shape_factor <2> (amrex::Real* const sx, amrex::Real xmid){ + const int j = (int) (xmid+0.5); + const amrex::Real xint = xmid-j; + sx[0] = 0.5*(0.5-xint)*(0.5-xint); + sx[1] = 0.75-xint*xint; + sx[2] = 0.5*(0.5+xint)*(0.5+xint); + // index of the leftmost cell where particle deposits + return j-1; +} + +// Compute shape factor for order 3. +template <> +AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE +int compute_shape_factor <3> (amrex::Real* const sx, amrex::Real xmid){ + const int j = (int) xmid; + const amrex::Real xint = xmid-j; + sx[0] = 1.0/6.0*(1.0-xint)*(1.0-xint)*(1.0-xint); + sx[1] = 2.0/3.0-xint*xint*(1-xint/2.0); + sx[2] = 2.0/3.0-(1-xint)*(1-xint)*(1.0-0.5*(1-xint)); + sx[3] = 1.0/6.0*xint*xint*xint; + // index of the leftmost cell where particle deposits + return j-1; +} + +// Compute shifted shape factor and return index of leftmost cell where +// particle writes, for Esirkepov algorithm. +// Specialized templates are defined below for orders 1, 2 and 3. +template <int depos_order> +AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE +int compute_shifted_shape_factor (amrex::Real* const sx, + const amrex::Real x_old, + const int i_new); + +// Compute shape factor for order 1. +template <> +AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE +int compute_shifted_shape_factor <1> (amrex::Real* const sx, + const amrex::Real x_old, + const int i_new){ + const int i = (int) x_old; + const int i_shift = i - i_new; + const amrex::Real xint = x_old - i; + sx[1+i_shift] = 1.0 - xint; + sx[2+i_shift] = xint; + return i; +} + +// Compute shape factor for order 2. +template <> +AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE +int compute_shifted_shape_factor <2> (amrex::Real* const sx, + const amrex::Real x_old, + const int i_new){ + const int i = (int) (x_old+0.5); + const int i_shift = i - (i_new + 1); + const amrex::Real xint = x_old - i; + sx[1+i_shift] = 0.5*(0.5-xint)*(0.5-xint); + sx[2+i_shift] = 0.75-xint*xint; + sx[3+i_shift] = 0.5*(0.5+xint)*(0.5+xint); + // index of the leftmost cell where particle deposits + return i-1; +} + +// Compute shape factor for order 3. +template <> +AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE +int compute_shifted_shape_factor <3> (amrex::Real* const sx, + const amrex::Real x_old, + const int i_new){ + const int i = (int) x_old; + const int i_shift = i - (i_new + 1); + const amrex::Real xint = x_old - i; + sx[1+i_shift] = 1.0/6.0*(1.0-xint)*(1.0-xint)*(1.0-xint); + sx[2+i_shift] = 2.0/3.0-xint*xint*(1-xint/2.0); + sx[3+i_shift] = 2.0/3.0-(1-xint)*(1-xint)*(1.0-0.5*(1-xint)); + sx[4+i_shift] = 1.0/6.0*xint*xint*xint; + // index of the leftmost cell where particle deposits + return i-1; +} + +#endif // SHAPEFACTORS_H_ |