// Copyright (c) 2017 Advanced Micro Devices, Inc. All rights reserved.
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#ifndef ROCRAND_LOG_NORMAL_H_
#define ROCRAND_LOG_NORMAL_H_

#ifndef FQUALIFIERS
#define FQUALIFIERS __forceinline__ __device__
#endif // FQUALIFIERS

/** \rocrand_internal \addtogroup rocranddevice
 *
 *  @{
 */

#include <math.h>

#include "rocrand_philox4x32_10.h"
#include "rocrand_mrg32k3a.h"
#include "rocrand_xorwow.h"
#include "rocrand_sobol32.h"
#include "rocrand_mtgp32.h"

#include "rocrand_normal.h"

/**
 * \brief Returns a log-normally distributed \p float value.
 *
 * Generates and returns a log-normally distributed \p float value using Philox
 * generator in \p state, and increments position of the generator by one.
 * The function uses the Box-Muller transform method to generate two normally distributed
 * values, transforms them to log-normally distributed values, returns first of them, and saves
 * the second to be returned on the next call.
 *
 * \param state  - Pointer to a state to use
 * \param mean   - Mean of the related log-normal distribution
 * \param stddev - Standard deviation of the related log-normal distribution
 *
 * \return Log-normally distributed \p float value
 */
#ifndef ROCRAND_DETAIL_PHILOX_BM_NOT_IN_STATE
FQUALIFIERS
float rocrand_log_normal(rocrand_state_philox4x32_10 * state, float mean, float stddev)
{
    typedef rocrand_device::detail::engine_boxmuller_helper<rocrand_state_philox4x32_10> bm_helper;

    if(bm_helper::has_float(state))
    {
        return expf(mean + (stddev * bm_helper::get_float(state)));
    }
    float2 r = rocrand_device::detail::normal_distribution2(rocrand(state), rocrand(state));
    bm_helper::save_float(state, r.y);
    return expf(mean + (stddev * r.x));
}
#endif // ROCRAND_DETAIL_PHILOX_BM_NOT_IN_STATE

/**
 * \brief Returns two log-normally distributed \p float values.
 *
 * Generates and returns two log-normally distributed \p float values using Philox
 * generator in \p state, and increments position of the generator by two.
 * The function uses the Box-Muller transform method to generate two normally distributed
 * values, transforms them to log-normally distributed values, and returns both.
 *
 * \param state  - Pointer to a state to use
 * \param mean   - Mean of the related log-normal distribution
 * \param stddev - Standard deviation of the related log-normal distribution
 *
 * \return Two log-normally distributed \p float value as \p float2
 */
FQUALIFIERS
float2 rocrand_log_normal2(rocrand_state_philox4x32_10 * state, float mean, float stddev)
{
    float2 r = rocrand_device::detail::normal_distribution2(rocrand(state), rocrand(state));
    return float2 {
        expf(mean + (stddev * r.x)),
        expf(mean + (stddev * r.y))
    };
}

/**
 * \brief Returns four log-normally distributed \p float values.
 *
 * Generates and returns four log-normally distributed \p float values using Philox
 * generator in \p state, and increments position of the generator by four.
 * The function uses the Box-Muller transform method to generate four normally distributed
 * values, transforms them to log-normally distributed values, and returns them.
 *
 * \param state  - Pointer to a state to use
 * \param mean   - Mean of the related log-normal distribution
 * \param stddev - Standard deviation of the related log-normal distribution
 *
 * \return Four log-normally distributed \p float value as \p float4
 */
FQUALIFIERS
float4 rocrand_log_normal4(rocrand_state_philox4x32_10 * state, float mean, float stddev)
{
    float4 r = rocrand_device::detail::normal_distribution4(rocrand4(state));
    return float4 {
        expf(mean + (stddev * r.x)),
        expf(mean + (stddev * r.y)),
        expf(mean + (stddev * r.z)),
        expf(mean + (stddev * r.w))
    };
}

/**
 * \brief Returns a log-normally distributed \p double values.
 *
 * Generates and returns a log-normally distributed \p double value using Philox
 * generator in \p state, and increments position of the generator by two.
 * The function uses the Box-Muller transform method to generate two normally distributed
 * \p double values, transforms them to log-normally distributed \p double values, returns
 * first of them, and saves the second to be returned on the next call.
 *
 * \param state  - Pointer to a state to use
 * \param mean   - Mean of the related log-normal distribution
 * \param stddev - Standard deviation of the related log-normal distribution
 *
 * \return Log-normally distributed \p double value
 */
#ifndef ROCRAND_DETAIL_PHILOX_BM_NOT_IN_STATE
FQUALIFIERS
double rocrand_log_normal_double(rocrand_state_philox4x32_10 * state, double mean, double stddev)
{
    typedef rocrand_device::detail::engine_boxmuller_helper<rocrand_state_philox4x32_10> bm_helper;

    if(bm_helper::has_double(state))
    {
        return exp(mean + (stddev * bm_helper::get_double(state)));
    }
    double2 r = rocrand_device::detail::normal_distribution_double2(rocrand4(state));
    bm_helper::save_double(state, r.y);
    return exp(mean + r.x * stddev);
}
#endif // ROCRAND_DETAIL_PHILOX_BM_NOT_IN_STATE

/**
 * \brief Returns two log-normally distributed \p double values.
 *
 * Generates and returns two log-normally distributed \p double values using Philox
 * generator in \p state, and increments position of the generator by four.
 * The function uses the Box-Muller transform method to generate two normally distributed
 * values, transforms them to log-normally distributed values, and returns both.
 *
 * \param state  - Pointer to a state to use
 * \param mean   - Mean of the related log-normal distribution
 * \param stddev - Standard deviation of the related log-normal distribution
 *
 * \return Two log-normally distributed \p double values as \p double2
 */
FQUALIFIERS
double2 rocrand_log_normal_double2(rocrand_state_philox4x32_10 * state, double mean, double stddev)
{
    double2 r = rocrand_device::detail::normal_distribution_double2(rocrand4(state));
    return double2 {
        exp(mean + (stddev * r.x)),
        exp(mean + (stddev * r.y))
    };
}

/**
 * \brief Returns four log-normally distributed \p double values.
 *
 * Generates and returns four log-normally distributed \p double values using Philox
 * generator in \p state, and increments position of the generator by eight.
 * The function uses the Box-Muller transform method to generate four normally distributed
 * values, transforms them to log-normally distributed values, and returns them.
 *
 * \param state  - Pointer to a state to use
 * \param mean   - Mean of the related log-normal distribution
 * \param stddev - Standard deviation of the related log-normal distribution
 *
 * \return Four log-normally distributed \p double values as \p double4
 */
FQUALIFIERS
double4 rocrand_log_normal_double4(rocrand_state_philox4x32_10 * state, double mean, double stddev)
{
    double2 r1, r2;
    r1 = rocrand_log_normal_double2(state, mean, stddev);
    r2 = rocrand_log_normal_double2(state, mean, stddev);
    return double4 {
        r1.x, r1.y, r2.x, r2.y
    };
}

/**
 * \brief Returns a log-normally distributed \p float value.
 *
 * Generates and returns a log-normally distributed \p float value using MRG32k3a
 * generator in \p state, and increments position of the generator by one.
 * The function uses the Box-Muller transform method to generate two normally distributed
 * values, transforms them to log-normally distributed values, returns first of them,
 * and saves the second to be returned on the next call.
 *
 * \param state  - Pointer to a state to use
 * \param mean   - Mean of the related log-normal distribution
 * \param stddev - Standard deviation of the related log-normal distribution
 *
 * \return Log-normally distributed \p float value
 */
#ifndef ROCRAND_DETAIL_MRG32K3A_BM_NOT_IN_STATE
FQUALIFIERS
float rocrand_log_normal(rocrand_state_mrg32k3a * state, float mean, float stddev)
{
    typedef rocrand_device::detail::engine_boxmuller_helper<rocrand_state_mrg32k3a> bm_helper;

    if(bm_helper::has_float(state))
    {
        return expf(mean + (stddev * bm_helper::get_float(state)));
    }
    float2 r = rocrand_device::detail::mrg_normal_distribution2(rocrand(state), rocrand(state));
    bm_helper::save_float(state, r.y);
    return expf(mean + (stddev * r.x));
}
#endif // ROCRAND_DETAIL_MRG32K3A_BM_NOT_IN_STATE

/**
 * \brief Returns two log-normally distributed \p float values.
 *
 * Generates and returns two log-normally distributed \p float values using MRG32k3a
 * generator in \p state, and increments position of the generator by two.
 * The function uses the Box-Muller transform method to generate two normally distributed
 * values, transforms them to log-normally distributed values, and returns both.
 *
 * \param state  - Pointer to a state to use
 * \param mean   - Mean of the related log-normal distribution
 * \param stddev - Standard deviation of the related log-normal distribution
 *
 * \return Two log-normally distributed \p float value as \p float2
 */
FQUALIFIERS
float2 rocrand_log_normal2(rocrand_state_mrg32k3a * state, float mean, float stddev)
{
    float2 r = rocrand_device::detail::mrg_normal_distribution2(rocrand(state), rocrand(state));
    return float2 {
        expf(mean + (stddev * r.x)),
        expf(mean + (stddev * r.y))
    };
}

/**
 * \brief Returns a log-normally distributed \p double value.
 *
 * Generates and returns a log-normally distributed \p double value using MRG32k3a
 * generator in \p state, and increments position of the generator by one.
 * The function uses the Box-Muller transform method to generate two normally distributed
 * \p double values, transforms them to log-normally distributed \p double values, returns
 * first of them, and saves the second to be returned on the next call.
 *
 * \param state  - Pointer to a state to use
 * \param mean   - Mean of the related log-normal distribution
 * \param stddev - Standard deviation of the related log-normal distribution
 *
 * \return Log-normally distributed \p double value
 */
#ifndef ROCRAND_DETAIL_MRG32K3A_BM_NOT_IN_STATE
FQUALIFIERS
double rocrand_log_normal_double(rocrand_state_mrg32k3a * state, double mean, double stddev)
{
    typedef rocrand_device::detail::engine_boxmuller_helper<rocrand_state_mrg32k3a> bm_helper;

    if(bm_helper::has_double(state))
    {
        return exp(mean + (stddev * bm_helper::get_double(state)));
    }
    double2 r = rocrand_device::detail::mrg_normal_distribution_double2(rocrand(state), rocrand(state));
    bm_helper::save_double(state, r.y);
    return exp(mean + r.x * stddev);
}
#endif // ROCRAND_DETAIL_MRG32K3A_BM_NOT_IN_STATE

/**
 * \brief Returns two log-normally distributed \p double values.
 *
 * Generates and returns two log-normally distributed \p double values using MRG32k3a
 * generator in \p state, and increments position of the generator by two.
 * The function uses the Box-Muller transform method to generate two normally distributed
 * values, transforms them to log-normally distributed values, and returns both.
 *
 * \param state  - Pointer to a state to use
 * \param mean   - Mean of the related log-normal distribution
 * \param stddev - Standard deviation of the related log-normal distribution
 *
 * \return Two log-normally distributed \p double values as \p double2
 */
FQUALIFIERS
double2 rocrand_log_normal_double2(rocrand_state_mrg32k3a * state, double mean, double stddev)
{
    double2 r = rocrand_device::detail::mrg_normal_distribution_double2(rocrand(state), rocrand(state));
    return double2 {
        exp(mean + (stddev * r.x)),
        exp(mean + (stddev * r.y))
    };
}

/**
 * \brief Returns a log-normally distributed \p float value.
 *
 * Generates and returns a log-normally distributed \p float value using XORWOW
 * generator in \p state, and increments position of the generator by one.
 * The function uses the Box-Muller transform method to generate two normally distributed
 * values, transforms them to log-normally distributed values, returns first of them,
 * and saves the second to be returned on the next call.
 *
 * \param state  - Pointer to a state to use
 * \param mean   - Mean of the related log-normal distribution
 * \param stddev - Standard deviation of the related log-normal distribution
 *
 * \return Log-normally distributed \p float value
 */
#ifndef ROCRAND_DETAIL_XORWOW_BM_NOT_IN_STATE
FQUALIFIERS
float rocrand_log_normal(rocrand_state_xorwow * state, float mean, float stddev)
{
    typedef rocrand_device::detail::engine_boxmuller_helper<rocrand_state_xorwow> bm_helper;

    if(bm_helper::has_float(state))
    {
        return expf(mean + (stddev * bm_helper::get_float(state)));
    }
    float2 r = rocrand_device::detail::normal_distribution2(rocrand(state), rocrand(state));
    bm_helper::save_float(state, r.y);
    return expf(mean + (stddev * r.x));
}
#endif // ROCRAND_DETAIL_XORWOW_BM_NOT_IN_STATE

/**
 * \brief Returns two log-normally distributed \p float values.
 *
 * Generates and returns two log-normally distributed \p float values using XORWOW
 * generator in \p state, and increments position of the generator by two.
 * The function uses the Box-Muller transform method to generate two normally distributed
 * values, transforms them to log-normally distributed values, and returns both.
 *
 * \param state  - Pointer to a state to use
 * \param mean   - Mean of the related log-normal distribution
 * \param stddev - Standard deviation of the related log-normal distribution
 *
 * \return Two log-normally distributed \p float value as \p float2
 */
FQUALIFIERS
float2 rocrand_log_normal2(rocrand_state_xorwow * state, float mean, float stddev)
{
    float2 r = rocrand_device::detail::normal_distribution2(rocrand(state), rocrand(state));
    return float2 {
        expf(mean + (stddev * r.x)),
        expf(mean + (stddev * r.y))
    };
}

/**
 * \brief Returns a log-normally distributed \p double value.
 *
 * Generates and returns a log-normally distributed \p double value using XORWOW
 * generator in \p state, and increments position of the generator by two.
 * The function uses the Box-Muller transform method to generate two normally distributed
 * \p double values, transforms them to log-normally distributed \p double values, returns
 * first of them, and saves the second to be returned on the next call.
 *
 * \param state  - Pointer to a state to use
 * \param mean   - Mean of the related log-normal distribution
 * \param stddev - Standard deviation of the related log-normal distribution
 *
 * \return Log-normally distributed \p double value
 */
#ifndef ROCRAND_DETAIL_XORWOW_BM_NOT_IN_STATE
FQUALIFIERS
double rocrand_log_normal_double(rocrand_state_xorwow * state, double mean, double stddev)
{
    typedef rocrand_device::detail::engine_boxmuller_helper<rocrand_state_xorwow> bm_helper;

    if(bm_helper::has_double(state))
    {
        return exp(mean + (stddev * bm_helper::get_double(state)));
    }
    double2 r = rocrand_device::detail::normal_distribution_double2(
        uint4 { rocrand(state), rocrand(state), rocrand(state), rocrand(state) }
    );
    bm_helper::save_double(state, r.y);
    return exp(mean + (stddev * r.x));
}
#endif // ROCRAND_DETAIL_XORWOW_BM_NOT_IN_STATE

/**
 * \brief Returns two log-normally distributed \p double values.
 *
 * Generates and returns two log-normally distributed \p double values using XORWOW
 * generator in \p state, and increments position of the generator by four.
 * The function uses the Box-Muller transform method to generate two normally distributed
 * values, transforms them to log-normally distributed values, and returns both.
 *
 * \param state  - Pointer to a state to use
 * \param mean   - Mean of the related log-normal distribution
 * \param stddev - Standard deviation of the related log-normal distribution
 *
 * \return Two log-normally distributed \p double values as \p double2
 */
FQUALIFIERS
double2 rocrand_log_normal_double2(rocrand_state_xorwow * state, double mean, double stddev)
{
    double2 r = rocrand_device::detail::normal_distribution_double2(
        uint4 { rocrand(state), rocrand(state), rocrand(state), rocrand(state) }
    );
    return double2 {
        exp(mean + (stddev * r.x)),
        exp(mean + (stddev * r.y))
    };
}

/**
 * \brief Returns a log-normally distributed \p float value.
 *
 * Generates and returns a log-normally distributed \p float value using MTGP32
 * generator in \p state, and increments position of the generator by one.
 *
 * \param state  - Pointer to a state to use
 * \param mean   - Mean of the related log-normal distribution
 * \param stddev - Standard deviation of the related log-normal distribution
 *
 * \return Log-normally distributed \p float value
 */
FQUALIFIERS
float rocrand_log_normal(rocrand_state_mtgp32 * state, float mean, float stddev)
{
    float r = rocrand_device::detail::normal_distribution(rocrand(state));
    return expf(mean + (stddev * r));
}

/**
 * \brief Returns a log-normally distributed \p double value.
 *
 * Generates and returns a log-normally distributed \p double value using MTGP32
 * generator in \p state, and increments position of the generator by one.
 *
 * \param state  - Pointer to a state to use
 * \param mean   - Mean of the related log-normal distribution
 * \param stddev - Standard deviation of the related log-normal distribution
 *
 * \return Log-normally distributed \p double value
 */
FQUALIFIERS
double rocrand_log_normal_double(rocrand_state_mtgp32 * state, double mean, double stddev)
{
    double r = rocrand_device::detail::normal_distribution_double(rocrand(state));
    return exp(mean + (stddev * r));
}

/**
 * \brief Returns a log-normally distributed \p float value.
 *
 * Generates and returns a log-normally distributed \p float value using SOBOL32
 * generator in \p state, and increments position of the generator by one.
 *
 * \param state  - Pointer to a state to use
 * \param mean   - Mean of the related log-normal distribution
 * \param stddev - Standard deviation of the related log-normal distribution
 *
 * \return Log-normally distributed \p float value
 */
FQUALIFIERS
float rocrand_log_normal(rocrand_state_sobol32 * state, float mean, float stddev)
{
    float r = rocrand_device::detail::normal_distribution(rocrand(state));
    return expf(mean + (stddev * r));
}

/**
 * \brief Returns a log-normally distributed \p double value.
 *
 * Generates and returns a log-normally distributed \p double value using SOBOL32
 * generator in \p state, and increments position of the generator by one.
 *
 * \param state  - Pointer to a state to use
 * \param mean   - Mean of the related log-normal distribution
 * \param stddev - Standard deviation of the related log-normal distribution
 *
 * \return Log-normally distributed \p double value
 */
FQUALIFIERS
double rocrand_log_normal_double(rocrand_state_sobol32 * state, double mean, double stddev)
{
    double r = rocrand_device::detail::normal_distribution_double(rocrand(state));
    return exp(mean + (stddev * r));
}


#endif // ROCRAND_LOG_NORMAL_H_

/** @} */ // end of group rocranddevice