Value conditioning (clamp / normalize / standardize)

data_condition conditions the values of data arrays without changing the geometry. It is a data operation, not a file format.

Mode	Transform
"clamp"	x → min(max(x, lo), hi)
"normalize"	affine map from the array's own [min, max] onto [lo, hi] (default [0, 1])
"standardize"	(x − mean) / stddev — zero mean, unit standard deviation

import meshioplusplus as mp

mesh = mp.read("part.vtu")

mesh = mp.data_condition(mesh, "point", ["T"], mode="clamp", lo=0.0, hi=100.0)
mesh = mp.data_condition(mesh, "cell", ["damage"], mode="normalize")
mesh = mp.data_condition(mesh, "point", ["T"], mode="standardize")

# Keep the original and write the result under a new name.
mesh = mp.data_condition(mesh, "point", ["T"], mode="normalize", suffix="_n")

Omit the name list to condition every array at that location.

Scope: components vs magnitude

scope="component" (the default) treats each trailing component independently, so each column of a vector array is conditioned on its own statistics.

scope="magnitude" computes the statistics over each row's Euclidean magnitude and rescales whole rows, preserving direction — the natural choice for a velocity or displacement field.

mp.data_condition(mesh, "point", ["velocity"], mode="normalize",
                  scope="magnitude")

Statistics

Statistics come from the finite values only — see the NaN policy. For a cell_data array they are computed jointly across all cell blocks before a single transform is applied to each: normalizing one block against its own extremes would make the pieces mutually incomparable.

Degenerate reductions are handled rather than producing NaN:

• normalize on a constant array (or one with no finite values) fills the target lower bound and warns.
• standardize with zero standard deviation fills 0 and warns.

Data types

clamp preserves the input dtype, so clamping an int32 array leaves it int32 (pass preserve_dtype=False to force float64). normalize and standardize always produce float64 — a rescaled integer field is not an integer field.

CLI

meshioplusplus data clamp     in.vtu out.vtu --point T --min 0 --max 100
meshioplusplus data normalize in.vtu out.vtu --cell damage --to 0,1
meshioplusplus data normalize in.vtu out.vtu --point T --zero-mean

--magnitude selects the magnitude scope, --suffix writes to a new name instead of in place, and --nan ignore|replace|fail (with --nan-value) selects the non-finite policy. See the CLI reference.

Other languages

• C API — mio_data_condition(mesh, location, names, count, mode, lo, hi, scope, nan_policy, nan_replacement, suffix) with the MIO_COND_*, MIO_SCOPE_* and MIO_NAN_* enumerations. See the C API reference.
• Fortran — m%data_condition(MIO_DATA_POINT, ["T"], mode=MIO_COND_NORMALIZE). See the Fortran reference.
• WebAssembly / JavaScript — dataCondition(mesh, "point", ["T"], "normalize", 0, 1, "component", "ignore", 0, ""). See the WebAssembly reference.