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axpy

outram_foam_basic_lib::fields::parallel

Function axpy 

Source 
pub fn axpy<T>(
    backend: ComputeBackend,
    y: &Field<T>,
    a: f64,
    x: &Field<T>,
) -> Field<T>
where
    T: Copy + Send + Sync + Add<Output = T> + Mul<f64, Output = T>,
Expand description

Fused combination c[i] = y[i] + a * x[i] (“axpy”), returning a new field.

This is the single most common shape in a solver timestep — adding a scaled explicit source, applying an under-relaxed correction, or advancing an explicit Euler update phi_new = phi + dt * ddt(phi). It is one fused pass, so the fields are traversed once instead of twice; that matters because these kernels are memory-bandwidth bound.

Units: y and a*x must be the same physical quantity.

§Panics

Panics if y.len() != x.len().

use outram_foam_basic_lib::compute::ComputeBackend;
use outram_foam_basic_lib::fields::field::Field;
use outram_foam_basic_lib::fields::parallel;

let y = Field::new(vec![1.0, 1.0]);
let x = Field::new(vec![4.0, 6.0]);
let c = parallel::axpy(ComputeBackend::Serial, &y, 0.5, &x);
assert_eq!(c.as_slice(), &[3.0, 4.0]);