/**
* get a col sparse vector of a matrix
*
* @param col col id
* @return a sparse vector of {index, value}
*/
public SparseVector column(int col) {
SparseVector sv = new SparseVector(numRows);
if (isCCSUsed) {
for (int j = colPtr[col]; j < colPtr[col + 1]; j++) {
int row = rowInd[j];
double val = get(row, col);
if (val != 0.0) sv.set(row, val);
}
} else {
for (int row = 0; row < numRows; row++) {
double val = get(row, col);
if (val != 0.0) sv.set(row, val);
}
}
return sv;
}
/**
* get a row sparse vector of a matrix
*
* @param row row id
* @return a sparse vector of {index, value}
*/
public SparseVector row(int row) {
SparseVector sv = new SparseVector(numColumns);
for (int j = rowPtr[row]; j < rowPtr[row + 1]; j++) {
int col = colInd[j];
double val = get(row, col);
if (val != 0.0) sv.set(col, val);
}
return sv;
}
@Test
public void testGetRawData() {
SparseVector vector = new SparseVector(Integer.MAX_VALUE);
double[] data = vector.getRawData();
assertTrue(data != null);
assertTrue(data.length == 0);
assertSame(data, vector.data);
assertEquals(data.length, vector.getRawIndex().length);
vector.set(2, 1.0);
vector.set(1, 0.0);
vector.set(4, 2.0);
data = vector.getRawData();
assertSame(data, vector.data);
assertEquals(data.length, vector.getRawIndex().length);
// In this case, the raw index is larger than the used, so the raw
// indices have more entries than the other one.
assertTrue(data.length > vector.getUsed());
assertTrue(data.length > vector.getIndex().length);
}
/**
* Unit test checking that the sparse vector does not end up ever using more than "size" elements.
*/
@Test
public void testOverAllocation() {
for (int d = 0; d < 10; d++) {
SparseVector v = new SparseVector(d, 0);
assertEquals(0, v.index.length);
assertEquals(0, v.data.length);
// Fill with non-zero elements.
for (int i = 0; i < d; i++) {
v.set(i, 1.0 + i);
}
assertEquals(d, v.index.length);
assertEquals(d, v.data.length);
}
}
@Override
public Vector slice(int from, int to) {
SparseVector res = new SparseVector();
int fi = find(from);
if (fi < 0) {
fi = -fi - 1;
}
int ti = find(to);
if (ti < 0) {
ti = -ti - 1;
}
for (int idx = fi; idx < ti; idx++) {
res.set(index(idx) - from, value(idx));
}
return res;
}