@tensorflow/tfjs-core
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Hardware-accelerated JavaScript library for machine intelligence
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JavaScript
;
/**
* @license
* Copyright 2018 Google Inc. 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.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License 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.
* =============================================================================
*/
Object.defineProperty(exports, "__esModule", { value: true });
var engine_1 = require("../engine");
var tensor_util_env_1 = require("../tensor_util_env");
var operation_1 = require("./operation");
var slice_1 = require("./slice");
var slice_util_1 = require("./slice_util");
/**
* Extracts a strided slice of a tensor.
*
* Roughly speaking, this op extracts a slice of size (end-begin)/stride from
* the given input tensor (x). Starting at the location specified by begin the
* slice continues by adding stride to the index until all dimensions are not
* less than end. Note that a stride can be negative, which causes a reverse
* slice.
*
* ```js
* const t = tf.tensor3d([1, 1, 1 ,2, 2, 2, 3, 3, 3, 4, 4, 4, 5, 5, 5, 6, 6, 6],
* [3, 2, 3]);
* t.stridedSlice([1, 0, 0], [2, 1, 3], [1, 1, 1]).print() // [[[3, 3, 3]]]
* t.stridedSlice([1, 0, 0], [2, 2, 3], [1, 1, 1]).print() // [[[3, 3, 3],
* // [4, 4, 4]]]
* t.stridedSlice([1, -1, 0], [2, -3, 3], [1, -1, 1]).print() // [[[4, 4, 4],
* // [3, 3, 3]]]
* ```
*
* @param x The tensor to stride slice.
* @param begin The coordinates to start the slice from.
* @param end: The coordinates to end the slice at.
* @param strides: The size of the slice.
* @param beginMask: If the ith bit of beginMask is set, begin[i] is ignored
* and the fullest possible range in that dimension is used instead.
* @param endMask: If the ith bit of endMask is set, end[i] is ignored
* and the fullest possible range in that dimension is used instead.
* @param shrinkAxisMask: a bitmask where bit i implies that
* the ith specification should shrink the dimensionality. begin and end must
* imply a slice of size 1 in the dimension.
*/
/** @doc {heading: 'Operations', subheading: 'Slicing and Joining'} */
function stridedSlice_(x, begin, end, strides, beginMask, endMask, ellipsisMask, newAxisMask, shrinkAxisMask) {
if (beginMask === void 0) { beginMask = 0; }
if (endMask === void 0) { endMask = 0; }
if (ellipsisMask === void 0) { ellipsisMask = 0; }
if (newAxisMask === void 0) { newAxisMask = 0; }
if (shrinkAxisMask === void 0) { shrinkAxisMask = 0; }
if (ellipsisMask !== 0) {
throw new Error('ellipsis mask is not yet supported');
}
if (newAxisMask !== 0) {
throw new Error('new axis mask is not yet supported');
}
var $x = tensor_util_env_1.convertToTensor(x, 'x', 'stridedSlice');
var nonStrided = strides.every(function (v) { return v === 1; });
if (nonStrided) {
var _a = slice_util_1.getStridedSlicedInfo($x.shape, begin, end, strides, beginMask, endMask, ellipsisMask, newAxisMask, shrinkAxisMask), beginIndex = _a[0], size = _a[1], shrinkAxis_1 = _a[2];
var outShape = size.filter(function (_, index) { return shrinkAxis_1.indexOf(index) === -1; });
return slice_1.slice($x, beginIndex, size).reshape(outShape);
}
return engine_1.ENGINE.runKernel(function (backend) { return backend.stridedSlice($x, begin, end, strides, beginMask, endMask, ellipsisMask, newAxisMask, shrinkAxisMask); }, { $x: $x });
}
exports.stridedSlice = operation_1.op({ stridedSlice_: stridedSlice_ });
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