Function calculate_swi 

pub fn calculate_swi(
    phase: &[f64],
    magnitude: &[f64],
    mask: &[u8],
    grid: &Grid,
    params: &SwiParams,
) -> Vec<f64>

Calculate SWI from unwrapped phase and magnitude

Pipeline: high-pass filter phase → create phase mask → multiply with magnitude.

Arguments

• phase - Unwrapped phase (single echo or combined)
• magnitude - Magnitude image (single echo or combined)
• mask - Binary brain mask
• grid - Volume grid (dimensions and voxel sizes)
• params - SWI algorithm parameters

Returns

SWI image (magnitude × phase mask)