Changes between Version 198 and Version 199 of UvmatHelp


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Timestamp:
Feb 17, 2016, 11:43:35 AM (8 years ago)
Author:
sommeria
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  • UvmatHelp

    v198 v199  
    316316----
    317317== 5 - Field structures ==
    318 === 5.1 Griding of data ===
     318=== 5.1 Griding of data === #tps
    319319Physical fields can be defined either on regular grids, either scattered on an unstructured set of positions. Some measurements techniques, like PIV or particle tracking, provided unstructured data, while most methods of analysis require data  on a regular grid. This can be done by interpolation, defining a projection on a plane (with '''[!ProjMode]''' ='interp...', see [#ProjObject next section]).  The three possibilities of griding are defined as follows:
    320320
     
    331331Fields may be alternatively obtained on a unstructured (grid-less) set of positions. The coordinates are then described by coordinate arrays X(nb_points), Y(nb_points), Z(nb_points). The corresponding field values are then represented as variables U(nb_point),V(nb_point) for each vector component, or alternatively by V(nb_points, j, i), where i, j possibly stand for vector or tensor components.
    332332
    333 - '''Thin plate shell (tps) interpolation:''' #tps
     333- '''Thin plate shell (tps) interpolation:'''
    334334
    335335This is a multi-dimensional generalisation of the spline interpolation/smoothing, an optimum way to interpolate data with minimal  curvature of the interpolating function. The result at an interpolation position vector ${\bf r}$ is expressed in the form, (see ThinPlateShell).