static double expE(double val) {
double pr = RobustMath.exp(val);
if (Double.isNaN(pr) || Double.isInfinite(pr)) {
try {
throw new Exception(
"Overflow error when taking exp of "
+ val
+ "\n Try running the CRF with the following option \"trainer ll\" to perform computations in the log-space.");
} catch (Exception e) {
System.out.println(e.getMessage());
e.printStackTrace();
return Double.MAX_VALUE;
}
}
return pr;
}
static double expLE(double val) {
double pr = RobustMath.exp(val);
if (Double.isNaN(pr) || Double.isInfinite(pr)) {
try {
throw new Exception(
"Overflow error when taking exp of "
+ val
+ " you might need to redesign feature values so as to not reach such high values");
} catch (Exception e) {
System.out.println(e.getMessage());
e.printStackTrace();
return Double.MAX_VALUE;
}
}
return pr;
}
protected double computeFunctionGradientLL(double lambda[], double grad[]) {
double logli = 0;
try {
for (int f = 0; f < lambda.length; f++) {
grad[f] = -1 * lambda[f] * params.invSigmaSquare;
logli -= ((lambda[f] * lambda[f]) * params.invSigmaSquare) / 2;
}
diter.startScan();
if (featureGenCache != null) featureGenCache.startDataScan();
for (int numRecord = 0; diter.hasNext(); numRecord++) {
DataSequence dataSeq = (DataSequence) diter.next();
if (featureGenCache != null) featureGenCache.nextDataIndex();
if (params.debugLvl > 1) {
Util.printDbg("Read next seq: " + numRecord + " logli " + logli);
}
alpha_Y.assign(0);
for (int f = 0; f < lambda.length; f++) ExpF[f] = RobustMath.LOG0;
if ((beta_Y == null) || (beta_Y.length < dataSeq.length())) {
beta_Y = new DenseDoubleMatrix1D[2 * dataSeq.length()];
for (int i = 0; i < beta_Y.length; i++) beta_Y[i] = new DenseDoubleMatrix1D(numY);
}
// compute beta values in a backward scan.
// also scale beta-values to 1 to avoid numerical problems.
beta_Y[dataSeq.length() - 1].assign(0);
for (int i = dataSeq.length() - 1; i > 0; i--) {
if (params.debugLvl > 2) {
/* Util.printDbg("Features fired");
featureGenerator.startScanFeaturesAt(dataSeq, i);
while (featureGenerator.hasNext()) {
Feature feature = featureGenerator.next();
Util.printDbg(feature.toString());
}
*/
}
// compute the Mi matrix
initMDone =
computeLogMi(
featureGenerator, lambda, dataSeq, i, Mi_YY, Ri_Y, false, reuseM, initMDone);
tmp_Y.assign(beta_Y[i]);
tmp_Y.assign(Ri_Y, sumFunc);
RobustMath.logMult(Mi_YY, tmp_Y, beta_Y[i - 1], 1, 0, false, edgeGen);
}
double thisSeqLogli = 0;
for (int i = 0; i < dataSeq.length(); i++) {
// compute the Mi matrix
initMDone =
computeLogMi(
featureGenerator, lambda, dataSeq, i, Mi_YY, Ri_Y, false, reuseM, initMDone);
// find features that fire at this position..
featureGenerator.startScanFeaturesAt(dataSeq, i);
if (i > 0) {
tmp_Y.assign(alpha_Y);
RobustMath.logMult(Mi_YY, tmp_Y, newAlpha_Y, 1, 0, true, edgeGen);
newAlpha_Y.assign(Ri_Y, sumFunc);
} else {
newAlpha_Y.assign(Ri_Y);
}
while (featureGenerator.hasNext()) {
Feature feature = featureGenerator.next();
int f = feature.index();
int yp = feature.y();
int yprev = feature.yprev();
float val = feature.value();
if ((dataSeq.y(i) == yp)
&& (((i - 1 >= 0) && (yprev == dataSeq.y(i - 1))) || (yprev < 0))) {
grad[f] += val;
thisSeqLogli += val * lambda[f];
if (params.debugLvl > 2) {
System.out.println("Feature fired " + f + " " + feature);
}
}
if (yprev < 0) {
ExpF[f] =
RobustMath.logSumExp(
ExpF[f], newAlpha_Y.get(yp) + RobustMath.log(val) + beta_Y[i].get(yp));
} else {
ExpF[f] =
RobustMath.logSumExp(
ExpF[f],
alpha_Y.get(yprev)
+ Ri_Y.get(yp)
+ Mi_YY.get(yprev, yp)
+ RobustMath.log(val)
+ beta_Y[i].get(yp));
}
}
alpha_Y.assign(newAlpha_Y);
if (params.debugLvl > 2) {
System.out.println("Alpha-i " + alpha_Y.toString());
System.out.println("Ri " + Ri_Y.toString());
System.out.println("Mi " + Mi_YY.toString());
System.out.println("Beta-i " + beta_Y[i].toString());
}
}
double lZx = RobustMath.logSumExp(alpha_Y);
thisSeqLogli -= lZx;
logli += thisSeqLogli;
// update grad.
for (int f = 0; f < grad.length; f++) {
grad[f] -= RobustMath.exp(ExpF[f] - lZx);
}
if (params.debugLvl > 1) {
System.out.println(
"Sequence "
+ thisSeqLogli
+ " logli "
+ logli
+ " log(Zx) "
+ lZx
+ " Zx "
+ Math.exp(lZx));
}
}
if (params.debugLvl > 2) {
for (int f = 0; f < lambda.length; f++) System.out.print(lambda[f] + " ");
System.out.println(" :x");
for (int f = 0; f < lambda.length; f++) System.out.print(grad[f] + " ");
System.out.println(" :g");
}
if (params.debugLvl > 0)
Util.printDbg(
"Iteration "
+ icall
+ " log-likelihood "
+ logli
+ " norm(grad logli) "
+ norm(grad)
+ " norm(x) "
+ norm(lambda));
} catch (Exception e) {
System.out.println("Alpha-i " + alpha_Y.toString());
System.out.println("Ri " + Ri_Y.toString());
System.out.println("Mi " + Mi_YY.toString());
e.printStackTrace();
System.exit(0);
}
return logli;
}