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Peter Eastman's avatar
Created OpenCL implementations of SETTLE and LangevinIntegrator (not yet fully debugged).  
Peter Eastman committed
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/**
 * Generate random numbers
 */
Peter Eastman's avatar
Added "const" and "restrict" to lots of kernel arguments to let the compiler do more optimizations  
Peter Eastman committed
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__kernel void generateRandomNumbers(int numValues, __global float4* restrict random, __global uint4* restrict seed) {
Peter Eastman's avatar
Created OpenCL implementations of SETTLE and LangevinIntegrator (not yet fully debugged).  
Peter Eastman committed
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    int index = get_global_id(0);
    uint4 state = seed[index];
    unsigned int carry = 0;
    while (index < numValues) {
        float4 value;

        // Generate first value.

        state.x = state.x * 69069 + 1;
        state.y ^= state.y << 13;
        state.y ^= state.y >> 17;
        state.y ^= state.y << 5;
        unsigned int k = (state.z >> 2) + (state.w >> 3) + (carry >> 2);
        unsigned int m = state.w + state.w + state.z + carry;
        state.z = state.w;
        state.w = m;
        carry = k >> 30;
        float x1 = (float)max(state.x + state.y + state.w, 0x00000001u) / (float)0xffffffff;
        state.x = state.x * 69069 + 1;
        state.y ^= state.y << 13;
        state.y ^= state.y >> 17;
        state.y ^= state.y << 5;
        x1 = sqrt(-2.0f * log(x1));
        k = (state.z >> 2) + (state.w >> 3) + (carry >> 2);
        m = state.w + state.w + state.z + carry;
        state.z = state.w;
        state.w = m;
        carry = k >> 30;
        float x2 = (float)(state.x + state.y + state.w) / (float)0xffffffff;
        value.x = x1 * cos(2.0f * 3.14159265f * x2);

        // Generate second value.

        state.x = state.x * 69069 + 1;
        state.y ^= state.y << 13;
        state.y ^= state.y >> 17;
        state.y ^= state.y << 5;
        k = (state.z >> 2) + (state.w >> 3) + (carry >> 2);
        m = state.w + state.w + state.z + carry;
        state.z = state.w;
        state.w = m;
        carry = k >> 30;
        float x3 = (float)max(state.x + state.y + state.w, 0x00000001u) / (float)0xffffffff;
        state.x = state.x * 69069 + 1;
        state.y ^= state.y << 13;
        state.y ^= state.y >> 17;
        state.y ^= state.y << 5;
        x3 = sqrt(-2.0f * log(x3));
        k = (state.z >> 2) + (state.w >> 3) + (carry >> 2);
        m = state.w + state.w + state.z + carry;
        state.z = state.w;
        state.w = m;
        carry = k >> 30;
        float x4 = (float)(state.x + state.y + state.w) / (float)0xffffffff;
        value.y = x3 * cos(2.0f * 3.14159265f * x4);

        // Generate third value.

        state.x = state.x * 69069 + 1;
        state.y ^= state.y << 13;
        state.y ^= state.y >> 17;
        state.y ^= state.y << 5;
        k = (state.z >> 2) + (state.w >> 3) + (carry >> 2);
        m = state.w + state.w + state.z + carry;
        state.z = state.w;
        state.w = m;
        carry = k >> 30;
        float x5 = (float)max(state.x + state.y + state.w, 0x00000001u) / (float)0xffffffff;
        state.x = state.x * 69069 + 1;
        state.y ^= state.y << 13;
        state.y ^= state.y >> 17;
        state.y ^= state.y << 5;
        x5 = sqrt(-2.0f * log(x5));
        k = (state.z >> 2) + (state.w >> 3) + (carry >> 2);
        m = state.w + state.w + state.z + carry;
        state.z = state.w;
        state.w = m;
        carry = k >> 30;
        float x6 = (float)(state.x + state.y + state.w) / (float)0xffffffff;
        value.z = x5 * cos(2.0f * 3.14159265f * x6);

        // Generate fourth value.

        state.x = state.x * 69069 + 1;
        state.y ^= state.y << 13;
        state.y ^= state.y >> 17;
        state.y ^= state.y << 5;
        k = (state.z >> 2) + (state.w >> 3) + (carry >> 2);
        m = state.w + state.w + state.z + carry;
        state.z = state.w;
        state.w = m;
        carry = k >> 30;
        float x7 = (float)max(state.x + state.y + state.w, 0x00000001u) / (float)0xffffffff;
        state.x = state.x * 69069 + 1;
        state.y ^= state.y << 13;
        state.y ^= state.y >> 17;
        state.y ^= state.y << 5;
        x7 = sqrt(-2.0f * log(x7));
        k = (state.z >> 2) + (state.w >> 3) + (carry >> 2);
        m = state.w + state.w + state.z + carry;
        state.z = state.w;
        state.w = m;
        carry = k >> 30;
        float x8 = (float)(state.x + state.y + state.w) / (float)0xffffffff;
        value.w = x7 * cos(2.0f * 3.14159265f * x8);

        // Record the values.

        random[index] = value;
        index += get_global_size(0);
    }
    seed[get_global_id(0)] = state;
}