/*
 * Copyright (c) 2015 Jiri Svoboda
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup libmath
 * @{
 */
/** @file
 */

#include <math.h>
#include <tanh.h>

/** Hyperbolic tangent (32-bit floating point)
 *
 * Compute hyperbolic tangent value.
 *
 * @param arg Hyperbolic angle
 *
 * @return Hyperbolic tangent.
 *
 */
float32_t float32_tanh(float32_t arg)
{
	float32_t em2x;

	if (arg > 9.0)
		return 1.0;
	if (arg < -9.0)
		return -1.0;

	em2x = exp_f32(-2.0 * arg);
	return (1.0 - em2x) / (1.0 + em2x);
}

/** Hyperbolic tangent (64-bit floating point)
 *
 * Compute hyperbolic tangent value.
 *
 * @param arg Hyperbolic angle
 *
 * @return Hyperbolic tangent.
 *
 */
float64_t float64_tanh(float64_t arg)
{
	float64_t em2x;

	if (arg > 19.0)
		return 1.0;
	if (arg < -19.0)
		return -1.0;

	em2x = exp_f64(-2.0 * arg);
	return (1.0 - em2x) / (1.0 + em2x);
}

/** @}
 */