Function run_nextqsm 

pub fn run_nextqsm(
    total_field_ppm: &[f64],
    mask: &[u8],
    metadata: &ScanMetadata,
    tile: Option<(usize, usize)>,
    progress: &mut dyn FnMut(usize, usize),
) -> Result<Vec<f64>, PipelineError>

Run NeXtQSM end-to-end from the total field (it does its own background removal), sourcing both weight files from the registry.

NeXtQSM spans BFR + dipole inversion, so unlike the other entries in InversionAlgorithm its input is the total field rather than a local one. It is reachable both ways: as InversionAlgorithm::Nextqsm through run_dipole_inversion, and directly here for a caller that wants it standalone.

total_field_ppm and mask are column-major (nx,ny,nz); the grid and B0 direction come from metadata. Requires the onnx feature; both weight files resolve through crate::models (supplied bytes first, as for every network). Returns susceptibility (ppm), masked.

Refuses a volume whose slices are not contiguous, like every other stage here: NeXtQSM’s unrolled data-consistency term is an FFT dipole convolution, so a gap invalidates it as thoroughly as it does a classical inversion. See ScanMetadata::require_contiguous_slices.