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@stdlib/math-base-special-gamma-lanczos-sum

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Calculate the Lanczos sum for the approximation of the gamma function.

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/* * @license Apache-2.0 * * Copyright (c) 2019 The Stdlib Authors. * * 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. */ // TypeScript Version: 4.1 /** * Calculates the Lanczos sum approximation. * * @param x - input value * @returns Lanczos sum approximation * * @example * var v = gammaLanczosSum( 4.0 ); * // returns ~950.366 * * @example * var v = gammaLanczosSum( -1.5 ); * // returns ~1373366.245 * * @example * var v = gammaLanczosSum( -0.5 ); * // returns ~-699841.735 * * @example * var v = gammaLanczosSum( 0.5 ); * // returns ~96074.186 * * @example * var v = gammaLanczosSum( 0.0 ); * // returns Infinity * * @example * var v = gammaLanczosSum( NaN ); * // returns NaN */ declare function gammaLanczosSum( x: number ): number; // EXPORTS // export = gammaLanczosSum;