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interpolateElectricPotential

Interpolate electric potential in electrostatic result at arbitrary spatial locations

    Description

    example

    Vintrp = interpolateElectricPotential(electrostaticresults,xq,yq) returns the interpolated electric potential values at the points specified in xq and yq.

    example

    Vintrp = interpolateElectricPotential(electrostaticresults,querypoints) returns the interpolated electric potential values at the points specified in querypoints.

    Examples

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    Create an electromagnetic model for electrostatic analysis.

    emagmodel = createpde('electromagnetic','electrostatic');

    Create a square geometry and include it in the model. Plot the geometry with the edge labels.

    R1 = [3,4,-1,1,1,-1,1,1,-1,-1]';
    g = decsg(R1, 'R1', ('R1')');
    geometryFromEdges(emagmodel,g);
    pdegplot(emagmodel,'EdgeLabels','on')
    xlim([-1.5 1.5])
    axis equal

    Figure contains an axes. The axes contains 5 objects of type line, text.

    Specify the vacuum permittivity in the SI system of units.

    emagmodel.VacuumPermittivity = 8.8541878128E-12;

    Specify the relative permittivity of the material.

    electromagneticProperties(emagmodel,'RelativePermittivity',1);

    Apply the voltage boundary conditions on the edges of the square.

    electromagneticBC(emagmodel,'Voltage',0,'Edge',[1 3]);
    electromagneticBC(emagmodel,'Voltage',1000,'Edge',[2 4]);

    Specify the charge density for the entire geometry.

    electromagneticSource(emagmodel,'ChargeDensity',5E-9);

    Generate the mesh.

    generateMesh(emagmodel);

    Solve the model and plot the electric potential.

    R = solve(emagmodel);
    pdeplot(emagmodel,'XYData',R.ElectricPotential, ...
                      'Contour','on')
    axis equal

    Figure contains an axes. The axes contains 12 objects of type patch, line.

    Interpolate the resulting electric potential to a grid covering the central portion of the geometry, for x and y from -0.5 to 0.5.

    v = linspace(-0.5,0.5,51);
    [X,Y] = meshgrid(v);
    
    Vintrp = interpolateElectricPotential(R,X,Y)
    Vintrp = 2601×1
    
      602.2959
      616.0208
      629.0498
      641.4049
      653.0828
      664.0757
      674.4209
      684.1432
      693.2704
      701.8026
          ⋮
    
    

    Reshape Vintrp and plot the resulting electric potential.

    Vintrp = reshape(Vintrp,size(X));
    
    figure
    contourf(X,Y,Vintrp)
    colormap(cool)
    colorbar

    Figure contains an axes. The axes contains an object of type contour.

    Alternatively, you can specify the grid by using a matrix of query points.

    querypoints = [X(:),Y(:)]';
    Vintrp = interpolateElectricPotential(R,querypoints);

    Input Arguments

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    Solution of an electrostatic problem, specified as an ElectrostaticResults object. Create electrostaticresults using the solve function.

    Example: electrostaticresults = solve(emagmodel)

    x-coordinate query points, specified as a real array. interpolateElectricPotential evaluates the electric potential at the coordinate points [xq(i) yq(i)] for every i. Because of this, xq and yq must have the same number of entries.

    interpolateElectricPotential converts the query points to column vectors xq(:) and yq(:). It returns electric potential values as a column vector of the same size. To ensure that the dimensions of the returned solution are consistent with the dimensions of the original query points, use reshape. For example, use Vintrp = reshape(Vintrp,size(xq)).

    Example: xq = [0.5 0.5 0.75 0.75]

    Data Types: double

    y-coordinate query points, specified as a real array. interpolateElectricPotential evaluates the electric potential at the coordinate points [xq(i) yq(i)] for every i. Because of this, xq and yq must have the same number of entries.

    interpolateElectricPotential converts the query points to column vectors xq(:) and yq(:). It returns electric potential values as a column vector of the same size. To ensure that the dimensions of the returned solution are consistent with the dimensions of the original query points, use reshape. For example, use Vintrp = reshape(Vintrp,size(yq)).

    Example: yq = [1 2 0 0.5]

    Data Types: double

    Query points, specified as a real matrix with two rows for 2-D geometry. interpolateElectricPotential evaluates the electric potential at the coordinate points querypoints(:,i) for every i, so each column of querypoints contains exactly one 2-D query point.

    Example: querypoints = [0.5 0.5 0.75 0.75; 1 2 0 0.5]

    Data Types: double

    Output Arguments

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    Electric potential at query points, returned as an FEStruct object with the properties representing the spatial components of the electric potential at the query points. For query points that are outside the geometry, Vintrp(i) = NaN. Properties of an FEStruct object are read-only.

    Introduced in R2021a