CODEWITHSUNDEEP
javaandroidopengl-esrenderscript
Benjie
Benjie

Reputation: 74

Array addition on android

Suppose i have 2 arrays of int

int[10] A; //[1,1,1,1,1,1,1,1,1,1]
int[10] B; //[2,2,2,2,2,2,2,2,2,2]

And the result of array C should be

int[10] C; //[3,3,3,3,3,3,3,3,3,3]

How should I get the result C instead of using a for loop to iterate through each A and B? In another words, is it possible to do parallel computation to save computation time by using the GPU?

I have read that by using RenderScript, it is possible to do such calculation. How should I go about doing it? I would be glad if someone can guide me along or point me to a reference site.

I have already read this and still confused: How to pass array values to and from Android RenderScript using Allocations

Will it be possible to use OpenGl ES to do this too? I read in this post that it is not possible to declare array: How to define constant array in GLSL (OpenGL ES 2.0)?

Current solution:

RenderScript Snippet

int32_t *A;
int32_t *B;

int32_t __attribute__((kernel)) kernelAdd(int32_t in) {
    int32_t C;
    C = A[in] + B[in];
    return C;
}

Java Snippet:

private void intAdd3(int[] A, int[] B) {
    RenderScript rs = RenderScript.create(this);
    ScriptC_rsintadd intaddscript = new ScriptC_rsintadd(rs,
            getResources(), R.raw.rsintadd);
    mScript = intaddscript;

    // Create allocation for arrays
    Allocation a = Allocation.createSized(rs, Element.I32(rs), A.length);
    a.copyFrom(A);
    intaddscript.bind_A(a);

    Allocation b = Allocation.createSized(rs, Element.I32(rs), B.length);
    b.copyFrom(B);
    intaddscript.bind_B(b);

    Allocation array = Allocation.createSized(rs, Element.I32(rs), SIZE);
    int[] array_size = new int[SIZE];
    for (int i = 0; i < SIZE; i++) {
        array_size[i] = i;
    }
    array.copyFrom(array_size);

    // create blank memory for c
    int[] C = new int[SIZE];
    Allocation c = Allocation.createSized(rs, Element.I32(rs), C.length);
    intaddscript.forEach_kernelAdd(array, c);

    c.copyTo(C);

    for (int i = 0; i < SIZE; i++) {
        System.out.println("intadd3" + i + ": " + C[i]);
    }
}

Upvotes: 1

Views: 170

Answers (2)

Aladin Q
Aladin Q

Reputation: 550

Assuming you have already allocated your arrays and they are available in the scope:

void __attribute__((kernel)) kernelAdd(uint32_t x) {
    C[x] = A[x] + B[x];
}

Take a look at http://developer.android.com/guide/topics/renderscript/compute.html#writing-an-rs-kernel

Upvotes: 1

Amitsharma
Amitsharma

Reputation: 1576

It May Help You

int[] a = { 1, 2 };
int[] b = { 3, 4 };
int[] l;

for (int i = 0; i < a.length; i++) {
        int c=i;
        for(int j=0;j<=b.length;j++)
        {
            int d=j;
            int e=c*d;
            // Make List Array here To insert e
            myList.add(e);

        }
    }
    System.out.println(myList);

This is not Perfect Solution but HelpFull

Upvotes: 0

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