/**
* This operation performs the tile updates needed by the generateTile() operation where
* interfaces should be considered.
*
* @param tile the tile to update
* @param slabM1 the slab one index less than (so above) the middle slab
* @param slab the middle slab
* @param dist the step distance
*/
private void updateTileByInterface(
Tile tile, Slab slabM1, Slab slab, double zInt, double rufInt) {
// Update the tile
tile.thickness = zInt * slab.interfaceWidth;
tile.scatteringLength =
0.5
* (slab.scatteringLength
+ slabM1.scatteringLength
+ rufInt * (slab.scatteringLength - slabM1.scatteringLength));
tile.trueAbsLength =
0.5
* (slab.trueAbsLength
+ slabM1.trueAbsLength
+ rufInt * (slab.trueAbsLength - slabM1.trueAbsLength));
tile.incAbsLength =
0.5
* (slab.incAbsLength
+ slabM1.incAbsLength
+ rufInt * (slab.incAbsLength - slabM1.incAbsLength));
return;
}
/**
* This operation performs the tile updates needed by the generateTile() operation.
*
* @param tile the tile to update
* @param slabM1 the slab one index less than (so above) the middle slab
* @param slab the middle slab
* @param slabP1 the slab one index greater than (so below) the middle slab
* @param dist the step distance
* @throws MathException Thrown if the error function cannot be evaluated
*/
private void updateTileByLayer(Tile updateSlab, Slab slabM1, Slab slab, Slab slabP1, double dist)
throws MathException {
// Compute the exponentials
double tExpFac = Erf.erf(cE * dist / slab.interfaceWidth);
double bExpFac = Erf.erf(cE * (dist - slab.thickness) / (slabP1.interfaceWidth));
// Update the slab properties
updateSlab.scatteringLength =
getTileValue(
slabM1.scatteringLength,
slab.scatteringLength,
slabP1.scatteringLength,
tExpFac,
bExpFac);
updateSlab.trueAbsLength =
getTileValue(
slabM1.trueAbsLength, slab.trueAbsLength, slabP1.trueAbsLength, tExpFac, bExpFac);
updateSlab.incAbsLength =
getTileValue(slabM1.incAbsLength, slab.incAbsLength, slabP1.incAbsLength, tExpFac, bExpFac);
return;
}
/**
* This operation generates a list of Tiles from the slabs with the corresponding number of
* ordinate steps.
*
* @param slabs the slabs of materials that define the system
* @param numRough the number of ordinate steps
* @param zInt FIXME! This array must be preallocated with a size n = maxRoughSize.
* @param rufInt FIXME! This array must be preallocated with a size n = maxRoughSize.
* @return the system of generated tiles
* @throws MathException Thrown if the error function cannot be calculated
*/
public Tile[] generateTiles(Slab[] slabs, int numRough, double[] zInt, double[] rufInt)
throws MathException {
// Local Declarations
int nGlay = 0;
double totalThickness = 0.0, gDMid = 0.0, step = 0.0, dist = 0.0;
// The number of slabs was not defined in the original code. I computed
// it by counting up the loops. This formula is currently off a little
// bit.
int numSlabs = 2 + 2 * (numRough / 2 + 1) + (slabs.length - 2) * (2 + numRough);
Tile[] generatedSlabs = new Tile[numSlabs];
// Create the slabs
for (int i = 0; i < numSlabs; i++) {
generatedSlabs[i] = new Slab();
}
// Evaluate the first half of the vacuum interface. Create the first
// slab.
Tile tmpSlab = generatedSlabs[0];
Slab refSlab = slabs[0], secondRefSlab = slabs[1], thirdRefSlab;
tmpSlab.scatteringLength = refSlab.scatteringLength;
tmpSlab.trueAbsLength = refSlab.trueAbsLength;
tmpSlab.incAbsLength = refSlab.incAbsLength;
tmpSlab.thickness = refSlab.thickness;
++nGlay;
// Create the other slabs for this half
for (int i = 0; i < numRough / 2 + 1; i++) {
tmpSlab = generatedSlabs[nGlay + i];
updateTileByInterface(tmpSlab, refSlab, secondRefSlab, zInt[i], rufInt[i]);
}
nGlay += numRough / 2 + 1;
// Evaluate the total normalized thickness of the surface
for (int i = 0; i < numRough + 1; i++) {
totalThickness += zInt[i];
}
// Calculate gradation of layers. Using slabs.length - 1 because the
// last layer is at index 4.
for (int i = 1; i < slabs.length - 1; i++) {
refSlab = slabs[i];
secondRefSlab = slabs[i + 1];
thirdRefSlab = slabs[i - 1];
// FIXME! Review gDMid calculation with John because it can be
// negative.
gDMid =
refSlab.thickness
- 0.5 * totalThickness * (refSlab.interfaceWidth + secondRefSlab.interfaceWidth);
if (gDMid <= 1.0e-10) {
// The interfaces are overlapping. Step through the entire slab
step = refSlab.thickness / (numRough + 1);
// Take the first half step
tmpSlab = generatedSlabs[nGlay];
tmpSlab.thickness = step / 2.0;
dist = step / 4.0;
updateTileByLayer(tmpSlab, thirdRefSlab, refSlab, secondRefSlab, dist);
++nGlay;
dist += 0.75 * step;
// Take the remaining steps
for (int j = 0; j < numRough; j++) {
tmpSlab = generatedSlabs[nGlay + j];
tmpSlab.thickness = step;
updateTileByLayer(tmpSlab, thirdRefSlab, refSlab, secondRefSlab, dist);
dist += step;
}
nGlay += numRough;
// Take final half step
tmpSlab = generatedSlabs[nGlay];
tmpSlab.thickness = step / 2.0;
dist = refSlab.thickness - step / 4.0;
updateTileByLayer(tmpSlab, thirdRefSlab, refSlab, secondRefSlab, dist);
++nGlay;
} else {
// Evaluate contributions from interfaces separately.
// Top interface
for (int j = numRough / 2 + 1; j < numRough + 1; j++) {
// Get the next slab and update it by considering the
// interface contribution.
tmpSlab = generatedSlabs[nGlay + j - numRough / 2 - 1];
updateTileByInterface(tmpSlab, thirdRefSlab, refSlab, zInt[j], rufInt[j]);
}
nGlay += numRough / 2 + 1;
// Central, bulk-like portion
tmpSlab = generatedSlabs[nGlay];
tmpSlab.scatteringLength = refSlab.scatteringLength;
tmpSlab.thickness = gDMid;
tmpSlab.trueAbsLength = refSlab.trueAbsLength;
tmpSlab.incAbsLength = refSlab.incAbsLength;
++nGlay;
// Bottom interface
for (int j = 0; j < numRough / 2 + 1; j++) {
tmpSlab = generatedSlabs[nGlay + j];
updateTileByInterface(tmpSlab, refSlab, secondRefSlab, zInt[j], rufInt[j]);
}
nGlay += numRough / 2 + 1;
}
}
// Evaluate substrate gradation
refSlab = slabs[slabs.length - 1];
secondRefSlab = slabs[slabs.length - 2];
for (int i = numRough / 2 + 1; i < numRough + 1; i++) {
tmpSlab = generatedSlabs[nGlay + i - numRough / 2 - 1];
updateTileByInterface(tmpSlab, secondRefSlab, refSlab, zInt[i], rufInt[i]);
}
nGlay += numRough / 2 + 1;
// Handle the last layer
refSlab = slabs[slabs.length - 1];
tmpSlab = generatedSlabs[nGlay];
tmpSlab.scatteringLength = refSlab.scatteringLength;
tmpSlab.trueAbsLength = refSlab.trueAbsLength;
tmpSlab.incAbsLength = refSlab.incAbsLength;
tmpSlab.thickness = refSlab.thickness;
++nGlay;
return generatedSlabs;
}
