/**
* Calculates the L2-norm of the sythesis waveforms of every leaf in the tree. This method should
* only be called on the root element.
*/
private void calcL2Norms() {
int i;
float wfs[][] = new float[2][];
double acc;
float l2n;
// While we are not done on the root element, compute basis
// functions and assign L2-norm
while (l2Norm < 0f) {
calcBasisWaveForms(wfs);
// Compute line L2-norm, which is the product of the line
// and column L2-norms
acc = 0.0;
for (i = wfs[0].length - 1; i >= 0; i--) {
acc += wfs[0][i] * wfs[0][i];
}
l2n = (float) Math.sqrt(acc);
// Compute column L2-norm
acc = 0.0;
for (i = wfs[1].length - 1; i >= 0; i--) {
acc += wfs[1][i] * wfs[1][i];
}
l2n *= (float) Math.sqrt(acc);
// Release waveforms
wfs[0] = null;
wfs[1] = null;
// Assign the value
assignL2Norm(l2n);
}
}
/**
* Calculates the basis waveform of the first leaf for which the L2-norm has not been calculated
* yet. This method searches recursively for the first leaf for which the value has not been
* calculated yet, and then calculates the L2-norm on the return path.
*
* <p>The wfs argument should be a size 2 array of float arrays (i.e. 2D array) and it must be of
* length 2 (or more). When returning, wfs[0] will contain the line waveform, and wfs[1] will
* contain the column waveform.
*
* <p>This method can not be called on an element that ahs a non-negative value in l2Norm, since
* that means that we are done.
*
* @param wfs An size 2 array where the line and column waveforms will be returned.
*/
private void calcBasisWaveForms(float wfs[][]) {
if (l2Norm < 0) {
// We are not finished with this element yet
if (isNode) {
// We are on a node => search on childs
if (subb_LL.l2Norm < 0f) {
subb_LL.calcBasisWaveForms(wfs);
wfs[0] = hFilter.getLPSynWaveForm(wfs[0], null);
wfs[1] = vFilter.getLPSynWaveForm(wfs[1], null);
} else if (subb_HL.l2Norm < 0f) {
subb_HL.calcBasisWaveForms(wfs);
wfs[0] = hFilter.getHPSynWaveForm(wfs[0], null);
wfs[1] = vFilter.getLPSynWaveForm(wfs[1], null);
} else if (subb_LH.l2Norm < 0f) {
subb_LH.calcBasisWaveForms(wfs);
wfs[0] = hFilter.getLPSynWaveForm(wfs[0], null);
wfs[1] = vFilter.getHPSynWaveForm(wfs[1], null);
} else if (subb_HH.l2Norm < 0f) {
subb_HH.calcBasisWaveForms(wfs);
wfs[0] = hFilter.getHPSynWaveForm(wfs[0], null);
wfs[1] = vFilter.getHPSynWaveForm(wfs[1], null);
} else {
// There is an error! If all childs have
// non-negative l2norm, then this node should have
// non-negative l2norm
throw new Error("You have found a bug in JJ2000!");
}
} else {
// This is a leaf, just use diracs (null is
// equivalent to dirac)
wfs[0] = new float[1];
wfs[0][0] = 1.0f;
wfs[1] = new float[1];
wfs[1][0] = 1.0f;
}
} else {
// This is an error! The calcBasisWaveForms() method is
// never called on an element with non-negative l2norm
throw new Error("You have found a bug in JJ2000!");
}
}