philox432.c.h

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 /*
 ***********************************************************************
 Copyright (c) 2015 Advanced Micro Devices, Inc. 
 All rights reserved.
 
 Redistribution and use in source and binary forms, with or without 
 modification, are permitted provided that the following conditions 
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 1. Redistributions of source code must retain the above copyright 
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 2. Redistributions in binary form must reproduce the above copyright 
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 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
 "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 
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 HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 
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 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 
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 */

#pragma once
#ifndef PRIVATE_PHILOX432_CH
#define PRIVATE_PHILOX432_CH

#include "Random123/philox.h" 

#define Philox432_NORM_cl_double    1.0 / 0x100000000L   // 1.0 /2^32 
#define Philox432_NORM_cl_float     2.32830644e-010f; 

clrngPhilox432Counter clrngPhilox432Add(clrngPhilox432Counter a, clrngPhilox432Counter b)
{
    clrngPhilox432Counter c;

    c.L.lsb = a.L.lsb + b.L.lsb;
    c.L.msb = a.L.msb + b.L.msb + (c.L.lsb < a.L.lsb);

    c.H.lsb = a.H.lsb + b.H.lsb + (c.L.msb < a.L.msb);
    c.H.msb = a.H.msb + b.H.msb + (c.H.lsb < a.H.lsb);

    return c;
}

clrngPhilox432Counter clrngPhilox432Substract(clrngPhilox432Counter a, clrngPhilox432Counter b)
{
    clrngPhilox432Counter c;

    c.L.lsb = a.L.lsb - b.L.lsb;
    c.L.msb = a.L.msb - b.L.msb - (c.L.lsb > a.L.lsb);

    c.H.lsb = a.H.lsb - b.H.lsb - (c.L.msb > a.L.msb);
    c.H.msb = a.H.msb - b.H.msb - (c.H.lsb > a.H.lsb);

    return c;
}

clrngStatus clrngPhilox432CopyOverStreams(size_t count, clrngPhilox432Stream* destStreams, const clrngPhilox432Stream* srcStreams)
{
    //Check params
    if (!destStreams)
        return clrngSetErrorString(CLRNG_INVALID_VALUE, "%s(): destStreams cannot be NULL", __func__);
    if (!srcStreams)
        return clrngSetErrorString(CLRNG_INVALID_VALUE, "%s(): srcStreams cannot be NULL", __func__);

    for (size_t i = 0; i < count; i++)
        destStreams[i] = srcStreams[i];

    return CLRNG_SUCCESS;
}

void clrngPhilox432GenerateDeck(clrngPhilox432StreamState *currentState)
{
    //Default key
    philox4x32_key_t k = { { currentState->key[0], currentState->key[1] } };

    //get the currect state
    philox4x32_ctr_t c = { { 0 } };
    c.v[0] = currentState->ctr.L.lsb;
    c.v[1] = currentState->ctr.L.msb;
    c.v[2] = currentState->ctr.H.lsb;
    c.v[3] = currentState->ctr.H.msb;

    //Generate 4 uint and store them into the stream state
    philox4x32_ctr_t r = philox4x32(c, k);
    currentState->deck[3] = r.v[0];
    currentState->deck[2] = r.v[1];
    currentState->deck[1] = r.v[2];
    currentState->deck[0] = r.v[3];
}

static cl_uint clrngPhilox432NextState(clrngPhilox432StreamState *currentState) {

    if (currentState->deckIndex == 0)
    {
        clrngPhilox432GenerateDeck(currentState);
    
    }

    cl_uint result = currentState->deck[currentState->deckIndex];
    
    currentState->deckIndex++;

    // Advance to the next Counter.
    if (currentState->deckIndex == 4) {

        clrngPhilox432Counter incBy1 = { { 0, 0 }, { 0, 1 } };
        currentState->ctr = clrngPhilox432Add(currentState->ctr, incBy1);

        currentState->deckIndex = 0;
        clrngPhilox432GenerateDeck(currentState);
    }

    return result;

}
// The following would be much cleaner with C++ templates instead of macros.

// We use an underscore on the r.h.s. to avoid potential recursion with certain
// preprocessors.
#define IMPLEMENT_GENERATE_FOR_TYPE(fptype) \
    \
    fptype clrngPhilox432RandomU01_##fptype(clrngPhilox432Stream* stream) { \
        return (clrngPhilox432NextState(&stream->current) + 0.5) * Philox432_NORM_##fptype; \
    } \
    \
    cl_int clrngPhilox432RandomInteger_##fptype(clrngPhilox432Stream* stream, cl_int i, cl_int j) { \
        return i + (cl_int)((j - i + 1) * clrngPhilox432RandomU01_##fptype(stream)); \
    } \
    \
    clrngStatus clrngPhilox432RandomU01Array_##fptype(clrngPhilox432Stream* stream, size_t count, fptype* buffer) { \
        if (!stream) \
            return clrngSetErrorString(CLRNG_INVALID_VALUE, "%s(): stream cannot be NULL", __func__); \
        if (!buffer) \
            return clrngSetErrorString(CLRNG_INVALID_VALUE, "%s(): buffer cannot be NULL", __func__); \
        for (size_t i = 0; i < count; i++)  \
            buffer[i] = clrngPhilox432RandomU01_##fptype(stream); \
        return CLRNG_SUCCESS; \
    } \
    \
    clrngStatus clrngPhilox432RandomIntegerArray_##fptype(clrngPhilox432Stream* stream, cl_int i, cl_int j, size_t count, cl_int* buffer) { \
        if (!stream) \
            return clrngSetErrorString(CLRNG_INVALID_VALUE, "%s(): stream cannot be NULL", __func__); \
        if (!buffer) \
            return clrngSetErrorString(CLRNG_INVALID_VALUE, "%s(): buffer cannot be NULL", __func__); \
        for (size_t k = 0; k < count; k++) \
            buffer[k] = clrngPhilox432RandomInteger_##fptype(stream, i, j); \
        return CLRNG_SUCCESS; \
    }

// On the host, implement everything.
// On the device, implement only what is required to avoid cluttering memory.
#if defined(CLRNG_SINGLE_PRECISION)  || !defined(__CLRNG_DEVICE_API)
IMPLEMENT_GENERATE_FOR_TYPE(cl_float)
#endif
#if !defined(CLRNG_SINGLE_PRECISION) || !defined(__CLRNG_DEVICE_API)
IMPLEMENT_GENERATE_FOR_TYPE(cl_double)
#endif

// Clean up macros, especially to avoid polluting device code.
#undef IMPLEMENT_GENERATE_FOR_TYPE



clrngStatus clrngPhilox432RewindStreams(size_t count, clrngPhilox432Stream* streams)
{
    //Check params
    if (!streams)
        return clrngSetErrorString(CLRNG_INVALID_VALUE, "%s(): streams cannot be NULL", __func__);
    //Reset current state to the stream initial state
    for (size_t j = 0; j < count; j++) {
#ifdef __CLRNG_DEVICE_API
#ifdef CLRNG_ENABLE_SUBSTREAMS
        streams[j].current = streams[j].substream = *streams[j].initial;
#else
        streams[j].current = *streams[j].initial;
#endif
#else
        streams[j].current = streams[j].substream = streams[j].initial;
#endif
}

    return CLRNG_SUCCESS;
}

#if defined(CLRNG_ENABLE_SUBSTREAMS) || !defined(__CLRNG_DEVICE_API)

clrngStatus clrngPhilox432RewindSubstreams(size_t count, clrngPhilox432Stream* streams)
{
    //Check params
    if (!streams)
        return clrngSetErrorString(CLRNG_INVALID_VALUE, "%s(): streams cannot be NULL", __func__);
    //Reset current state to the subStream initial state
    for (size_t j = 0; j < count; j++) {
        streams[j].current = streams[j].substream;
    }

    return CLRNG_SUCCESS;
}

void Philox432ResetNextSubStream(clrngPhilox432Stream* stream){

    //2^64 states
    clrngPhilox432Counter steps = { { 0, 1 }, { 0, 0 } };

    //move the substream counter 2^64 steps forward.
    stream->substream.ctr = clrngPhilox432Add(stream->substream.ctr, steps);

    clrngPhilox432RewindSubstreams(1, stream);
}

clrngStatus clrngPhilox432ForwardToNextSubstreams(size_t count, clrngPhilox432Stream* streams)
{
    //Check params
    if (!streams)
        return clrngSetErrorString(CLRNG_INVALID_VALUE, "%s(): streams cannot be NULL", __func__);

    for (size_t k = 0; k < count; k++) {

        Philox432ResetNextSubStream(&streams[k]);
    }

    return CLRNG_SUCCESS;
}

clrngStatus clrngPhilox432MakeOverSubstreams(clrngPhilox432Stream* stream, size_t count, clrngPhilox432Stream* substreams)
{
    for (size_t i = 0; i < count; i++) {
        clrngStatus err;
        // snapshot current stream into substreams[i]
        err = clrngPhilox432CopyOverStreams(1, &substreams[i], stream);
        if (err != CLRNG_SUCCESS)
            return err;
        // advance to next substream
        err = clrngPhilox432ForwardToNextSubstreams(1, stream);
        if (err != CLRNG_SUCCESS)
            return err;
    }
    return CLRNG_SUCCESS;
}

#endif

#endif // PRIVATE_Philox432_CH