ai.djl.ndarray.index.full.NDIndexFullSlice Maven / Gradle / Ivy
/*
* Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License"). You may not use this file except in compliance
* with the License. A copy of the License is located at
*
* http://aws.amazon.com/apache2.0/
*
* or in the "license" file accompanying this file. This file is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES
* OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions
* and limitations under the License.
*/
package ai.djl.ndarray.index.full;
import ai.djl.ndarray.index.NDIndex;
import ai.djl.ndarray.index.dim.NDIndexAll;
import ai.djl.ndarray.index.dim.NDIndexElement;
import ai.djl.ndarray.index.dim.NDIndexFixed;
import ai.djl.ndarray.index.dim.NDIndexSlice;
import ai.djl.ndarray.types.Shape;
import java.util.ArrayList;
import java.util.List;
import java.util.Optional;
/** An index as a slice on all dimensions where some dimensions can be squeezed. */
public final class NDIndexFullSlice {
private long[] min;
private long[] max;
private long[] step;
private int[] toSqueeze;
private Shape shape;
private Shape squeezedShape;
/**
* Constructs a {@link NDIndexFullSlice}.
*
* @param min the min for each axis
* @param max the max for each axis
* @param step the step for each axis
* @param toSqueeze the axes to squeeze after slicing
* @param shape the result shape (without squeezing)
* @param squeezedShape the result shape (with squeezing)
*/
private NDIndexFullSlice(
long[] min,
long[] max,
long[] step,
int[] toSqueeze,
Shape shape,
Shape squeezedShape) {
this.min = min;
this.max = max;
this.step = step;
this.toSqueeze = toSqueeze;
this.shape = shape;
this.squeezedShape = squeezedShape;
}
/**
* Returns (if possible) the {@link NDIndexFullSlice} representation of an {@link NDIndex}.
*
* @param index the index to represent
* @param target the shape of the array to index
* @return the full slice representation or nothing if it can't represent the index
*/
public static Optional fromIndex(NDIndex index, Shape target) {
if (!index.stream()
.allMatch(
ie ->
ie instanceof NDIndexAll
|| ie instanceof NDIndexFixed
|| ie instanceof NDIndexSlice)) {
return Optional.empty();
}
int ellipsisIndex = index.getEllipsisIndex();
int indDimensions = index.getRank();
int targetDimensions = target.dimension();
if (indDimensions > target.dimension()) {
throw new IllegalArgumentException(
"The index has too many dimensions - "
+ indDimensions
+ " dimensions for array with "
+ targetDimensions
+ " dimensions");
}
long[] min = new long[targetDimensions];
long[] max = new long[targetDimensions];
long[] step = new long[targetDimensions];
List toSqueeze = new ArrayList<>(targetDimensions);
long[] shape = new long[targetDimensions];
List squeezedShape = new ArrayList<>(targetDimensions);
if (ellipsisIndex == -1 || ellipsisIndex == indDimensions) {
// ellipsis in the end and non ellipsis case
for (int i = 0; i < indDimensions; i++) {
NDIndexElement ie = index.get(i);
addSliceInfo(ie, i, target, min, max, step, toSqueeze, shape, squeezedShape);
}
for (int i = indDimensions; i < target.dimension(); i++) {
padIndexAll(i, target, min, max, step, shape, squeezedShape);
}
} else if (ellipsisIndex == 0) {
// ellipsis in the beginning
int paddingDim = targetDimensions - indDimensions;
int i;
for (i = 0; i < paddingDim; ++i) {
padIndexAll(i, target, min, max, step, shape, squeezedShape);
}
for (; i < targetDimensions; ++i) {
NDIndexElement ie = index.get(i - paddingDim);
addSliceInfo(ie, i, target, min, max, step, toSqueeze, shape, squeezedShape);
}
} else {
// ellipsis in the middle
int paddingDim = targetDimensions - indDimensions;
int i;
for (i = 0; i < ellipsisIndex; ++i) {
NDIndexElement ie = index.get(i);
addSliceInfo(ie, i, target, min, max, step, toSqueeze, shape, squeezedShape);
}
for (; i < paddingDim + ellipsisIndex; ++i) {
padIndexAll(i, target, min, max, step, shape, squeezedShape);
}
for (; i < targetDimensions; ++i) {
NDIndexElement ie = index.get(i - paddingDim);
addSliceInfo(ie, i, target, min, max, step, toSqueeze, shape, squeezedShape);
}
}
int[] squeeze = toSqueeze.stream().mapToInt(i -> i).toArray();
NDIndexFullSlice fullSlice =
new NDIndexFullSlice(
min, max, step, squeeze, new Shape(shape), new Shape(squeezedShape));
return Optional.of(fullSlice);
}
private static void addSliceInfo(
NDIndexElement ie,
int i,
Shape target,
long[] min,
long[] max,
long[] step,
List toSqueeze,
long[] shape,
List squeezedShape) {
if (ie instanceof NDIndexFixed) {
NDIndexFixed fixed = ((NDIndexFixed) ie);
long rawIndex = fixed.getIndex();
min[i] = rawIndex < 0 ? Math.floorMod(rawIndex, target.get(i)) : rawIndex;
max[i] = min[i] + 1;
step[i] = 1;
toSqueeze.add(i);
shape[i] = 1;
} else if (ie instanceof NDIndexSlice) {
NDIndexSlice slice = (NDIndexSlice) ie;
long rawMin = Optional.ofNullable(slice.getMin()).orElse(0L);
min[i] = rawMin < 0 ? Math.floorMod(rawMin, target.get(i)) : rawMin;
long rawMax = Optional.ofNullable(slice.getMax()).orElse(target.size(i));
max[i] = rawMax < 0 ? Math.floorMod(rawMax, target.get(i)) : rawMax;
step[i] = Optional.ofNullable(slice.getStep()).orElse(1L);
shape[i] = (long) Math.ceil(((double) (max[i] - min[i])) / step[i]);
squeezedShape.add(shape[i]);
} else if (ie instanceof NDIndexAll) {
padIndexAll(i, target, min, max, step, shape, squeezedShape);
}
}
private static void padIndexAll(
int i,
Shape target,
long[] min,
long[] max,
long[] step,
long[] shape,
List squeezedShape) {
min[i] = 0;
max[i] = target.size(i);
step[i] = 1;
shape[i] = target.size(i);
squeezedShape.add(target.size(i));
}
/**
* Returns the slice min for each axis.
*
* @return the slice min for each axis
*/
public long[] getMin() {
return min;
}
/**
* Returns the slice max for each axis.
*
* @return the slice max for each axis
*/
public long[] getMax() {
return max;
}
/**
* Returns the slice step for each axis.
*
* @return the slice step for each axis
*/
public long[] getStep() {
return step;
}
/**
* Returns the squeeze array of axis.
*
* @return the squeeze array of axis
*/
public int[] getToSqueeze() {
return toSqueeze;
}
/**
* Returns the slice shape without squeezing.
*
* @return the slice shape without squeezing
*/
public Shape getShape() {
return shape;
}
/**
* Returns the slice shape with squeezing.
*
* @return the slice shape with squeezing
*/
public Shape getSqueezedShape() {
return squeezedShape;
}
}
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