Basic

Interpolate field value at physical coordinates (nearest-neighbor)

Interpolate field value at physical coordinates (nearest-neighbor)Returns the field value at the grid point nearest to the given physical coordinates. This uses simple rounding (not linear or higher-order). This is the preferred way to interpolate - free function instead of member.

Design Philosophy: Free functions enable extension via ADL and align with OpenPFC's "laboratory, not fortress" philosophy. Users can provide custom interpolation schemes without modifying DiscreteField.

Template Parameters

T	Field value type (double, complex, etc.)
D	Dimensionality (1, 2, or 3)

Parameters

field	The discrete field to interpolate
coordinates	Physical coordinates [x, y, z] to interpolate at

Returns

Reference to the field value at the nearest grid point (mutable)

usage

pfc::DiscreteField<double, 3> field({64,64,64}, {0,0,0},
                                     {0.0,0.0,0.0}, {1.0,1.0,1.0});
field.apply([](double x, double y, double z) { return x + y + z; });
 
// Interpolate at arbitrary coordinate (free function - preferred)
double& value = pfc::interpolate(field, {5.7, 10.2, 20.8});
value = 42.0;  // Can modify through reference