gather_direct.br

用于GPU通用计算的编程语言BrookGPU 0.4

// gather_direct.br
// Minimal acceptance test for gather functionality.
// It confirms that when we perform a gather with
// a constant index, the expected stream element
// is fetched.

#include <stdio.h>

kernel void gather1( float2 index, float a[100], out float b<> ) {
	b = a[ index.x ];
}

kernel void gather2( float2 index, float a[10][10], out float b<> ) {
	b = a[ index.xy ];
}

int main() {
	int i, j;
	float2 index = float2(3, 4);
	float a1< 100 >;
	float b1< 100 >;
	float a2< 10, 10 >;
	float b2< 10, 10 >;
	float input_a1[100];
	float output_b1[100];
	float input_a2[10][10];
	float output_b2[10][10];
	
	// initialize data
	for( i = 0; i < 10; i++ )
	{
		for( j = 0; j < 10; j++ )
		{
			input_a1[10*i+j] = (float)(10*i+j);
			input_a2[i][j] = (float)(10*i+j);
		}
	}
	streamRead( a1, input_a1 );
	streamRead( a2, input_a1 );
	
	gather1( index, a1, b1 );
	gather2( index, a2, b2 );
	
	streamWrite( b1, output_b1 );
	streamWrite( b2, output_b2 );
	
	for( i = 0; i < 10; i++ )
	{
		for( j = 0; j < 10; j++ )
			printf( "%3.2f ", output_b1[10*i+j] );
		printf("\n");
	}
	
	for( i = 0; i < 10; i++ )
	{
		for( j = 0; j < 10; j++ )
			printf( "%3.2f ", output_b2[i][j] );
		printf("\n");
	}
	
	return 0;
}