Paper - IDAV: Institute for Data Analysis and Visualization

20 · Lefohn, Kniss, Strzodka, Sengupta, and Owensnn(a)(b)Fig. 3: The Glift n-stack container stores a stack of n-length arrays (a) to support n-way parallel push and pop operations. We implement thestructure in Glift as a 1D virtual array stored in 2D physical memory (b).int maxNumN = 10000;StackType stack( maxNumN );✝The stack can store at most maxNumN number of n-sized arrays. Users may push either CPU-based or GPU-baseddata onto the stack. The following code demonstrates a GPU stack push:✞typedef ArrayGpu ArrayType;ArrayType data( 1000 );✆☎// ... initialize data array ...ArrayType::gpu_in_range r = data.gpu_in_single_range( 0, 1000 );stack.push( r );✝Push writes a stream of n input values into the physical memory locations from stack.top() to stack.top()+ n - 1 (see Figure 4). Note that the input to push is specified as a range of element iterators rather than a specificdata structure. This makes push compatible with any Glift data structure rather than just dense, 1D arrays.Pop removes the top n elements from the stack and returns a GPU input range iterator (Figure 4). This iterator canbe bound as input to a GPU computation over the specified range. Example C++ source code that pops two streamsfrom the stack, combines them in a subsequent kernel, and writes them to an array looks like:✞StackType::gpu_in_range result1 = stack.pop();StackType::gpu_in_range result2 = stack.pop();// ... Create Cg shader and instantiate Glift typesCGparameter result1Param = cgGetNamedParameter( prog, "result1" );result1.bind_for_read( result1Param );CGparameter result2Param = cgGetNamedParameter( prog, "result2" );ACM Transactions on Graphics, Vol. 25, No. 1, January 2006.✆☎