# 3.3.12. Cell and Face Weights File¶

## 3.3.12.1. Cell Weights¶

Cell weights files have the same format as model files. When creating cells weights:

• All cells must be assigned a weight values larger than 0! This is to ensure the problem is sufficiently well-conditioned.

• Model weight values should be set relative to a value of 1. This is to ensure the relative emphasis on model weights and surface weights is preserved. A value of 1 implies that no cell weighting is being applied.

• Large model weights ($$w \gg 1$$ ) are used for cells that we want to match the reference model.

• Small model weights ($$w \ll 1$$ ) are used for cells to reduce the impact of the reference model on the cells.

## 3.3.12.2. Interface Weights¶

Interface weights files contain the interface weights in x, y and z in a single column vectors; as the number of faces in x, y and z may differ. When creating interface weights:

• All interface weights must be larger than 0! This is to ensure the problem is sufficiently well-conditioned.

• Interface weight value should be set relative to a value of 1. This is to ensure the relative emphasis on model weights and surface weights is preserved. A value of 1 implies that no interface weighting is being applied.

• Large interface weights ($$w \gg 1$$ ) preserve gradients within reference model.

• Small interface weights ($$w \ll 1$$ ) results in smoother gradients within