@tensorflow/tfjs-core
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Hardware-accelerated JavaScript library for machine intelligence
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JavaScript
;
/**
* @license
* Copyright 2018 Google LLC. 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 });
/**
* Merges real and imaginary Float32Arrays into a single complex Float32Array.
*
* The memory layout is interleaved as follows:
* real: [r0, r1, r2]
* imag: [i0, i1, i2]
* complex: [r0, i0, r1, i1, r2, i2]
*
* This is the inverse of splitRealAndImagArrays.
*
* @param real The real values of the complex tensor values.
* @param imag The imag values of the complex tensor values.
* @returns A complex tensor as a Float32Array with merged values.
*/
function mergeRealAndImagArrays(real, imag) {
if (real.length !== imag.length) {
throw new Error("Cannot merge real and imag arrays of different lengths. real:" +
(real.length + ", imag: " + imag.length + "."));
}
var result = new Float32Array(real.length * 2);
for (var i = 0; i < result.length; i += 2) {
result[i] = real[i / 2];
result[i + 1] = imag[i / 2];
}
return result;
}
exports.mergeRealAndImagArrays = mergeRealAndImagArrays;
/**
* Splits a complex Float32Array into real and imag parts.
*
* The memory layout is interleaved as follows:
* complex: [r0, i0, r1, i1, r2, i2]
* real: [r0, r1, r2]
* imag: [i0, i1, i2]
*
* This is the inverse of mergeRealAndImagArrays.
*
* @param complex The complex tensor values.
* @returns An object with real and imag Float32Array components of the complex
* tensor.
*/
function splitRealAndImagArrays(complex) {
var real = new Float32Array(complex.length / 2);
var imag = new Float32Array(complex.length / 2);
for (var i = 0; i < complex.length; i += 2) {
real[i / 2] = complex[i];
imag[i / 2] = complex[i + 1];
}
return { real: real, imag: imag };
}
exports.splitRealAndImagArrays = splitRealAndImagArrays;
/**
* Extracts even indexed complex values in the given array.
* @param complex The complex tensor values
*/
function complexWithEvenIndex(complex) {
var len = Math.ceil(complex.length / 4);
var real = new Float32Array(len);
var imag = new Float32Array(len);
for (var i = 0; i < complex.length; i += 4) {
real[Math.floor(i / 4)] = complex[i];
imag[Math.floor(i / 4)] = complex[i + 1];
}
return { real: real, imag: imag };
}
exports.complexWithEvenIndex = complexWithEvenIndex;
/**
* Extracts odd indexed comple values in the given array.
* @param complex The complex tensor values
*/
function complexWithOddIndex(complex) {
var len = Math.floor(complex.length / 4);
var real = new Float32Array(len);
var imag = new Float32Array(len);
for (var i = 2; i < complex.length; i += 4) {
real[Math.floor(i / 4)] = complex[i];
imag[Math.floor(i / 4)] = complex[i + 1];
}
return { real: real, imag: imag };
}
exports.complexWithOddIndex = complexWithOddIndex;
/**
* Get the map representing a complex value in the given array.
* @param complex The complex tensor values.
* @param index An index of the target complex value.
*/
function getComplexWithIndex(complex, index) {
var real = complex[index * 2];
var imag = complex[index * 2 + 1];
return { real: real, imag: imag };
}
exports.getComplexWithIndex = getComplexWithIndex;
/**
* Insert a given complex value into the TypedArray.
* @param data The array in which the complex value is inserted.
* @param c The complex value to be inserted.
* @param index An index of the target complex value.
*/
function assignToTypedArray(data, real, imag, index) {
data[index * 2] = real;
data[index * 2 + 1] = imag;
}
exports.assignToTypedArray = assignToTypedArray;
/**
* Make the list of exponent terms used by FFT.
*/
function exponents(n, inverse) {
var real = new Float32Array(n / 2);
var imag = new Float32Array(n / 2);
for (var i = 0; i < Math.ceil(n / 2); i++) {
var x = (inverse ? 2 : -2) * Math.PI * (i / n);
real[i] = Math.cos(x);
imag[i] = Math.sin(x);
}
return { real: real, imag: imag };
}
exports.exponents = exponents;
/**
* Make the exponent term used by FFT.
*/
function exponent(k, n, inverse) {
var x = (inverse ? 2 : -2) * Math.PI * (k / n);
var real = Math.cos(x);
var imag = Math.sin(x);
return { real: real, imag: imag };
}
exports.exponent = exponent;
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