in flink-ml-lib/src/main/java/org/apache/flink/ml/feature/interaction/Interaction.java [98:178]
public Row map(Row value) {
int nnz = 1;
boolean hasSparse = false;
for (int i = 0; i < inputCols.length; ++i) {
Object obj = value.getField(inputCols[i]);
if (obj == null) {
return RowUtils.append(value, null);
}
if (obj instanceof DenseVector) {
featureSize[i] = ((Vector) obj).size();
if (featureIndices[i] == null || featureIndices[i].length != featureSize[i]) {
featureIndices[i] = new int[featureSize[i]];
for (int j = 0; j < featureSize[i]; ++j) {
featureIndices[i][j] = j;
}
}
featureValues[i] = ((DenseVector) obj).values;
nnz *= featureSize[i];
} else if (obj instanceof SparseVector) {
featureSize[i] = ((Vector) obj).size();
featureIndices[i] = ((SparseVector) obj).indices;
featureValues[i] = ((SparseVector) obj).values;
nnz *= ((SparseVector) obj).values.length;
hasSparse = true;
} else {
featureSize[i] = 1;
featureIndices[i] = new int[] {0};
featureValues[i] = new double[] {Double.parseDouble(obj.toString())};
}
}
Vector ret;
int featureIter = inputCols.length - 1;
if (hasSparse) {
int[] indices = new int[nnz];
double[] values = new double[nnz];
Arrays.fill(values, 1.0);
int offset = 1;
int size = 1;
while (featureIter >= 0) {
int[] prevIndices = featureIndices[featureIter];
double[] prevValues = featureValues[featureIter];
for (int i = 0; i < nnz / offset; ++i) {
int idxOffset = i * offset;
int idx = i % prevValues.length;
for (int j = 0; j < offset; ++j) {
values[idxOffset + j] *= prevValues[idx];
indices[idxOffset + j] += prevIndices[idx] * size;
}
}
offset *= prevValues.length;
size *= featureSize[featureIter--];
}
ret = Vectors.sparse(size, indices, values);
} else {
double[] values = new double[nnz];
Arrays.fill(values, 1.0);
int idxOffset = 1;
while (featureIter >= 0) {
double[] prevValues = featureValues[featureIter--];
for (int i = 0; i < nnz / idxOffset; ++i) {
int innerOffset = i * idxOffset;
int idx = i % prevValues.length;
for (int j = 0; j < idxOffset; ++j) {
values[innerOffset + j] *= prevValues[idx];
}
}
idxOffset *= prevValues.length;
}
ret = new DenseVector(values);
}
return RowUtils.append(value, ret);
}