Well, in simpler terms, it means we took the standard Basic Linear Algebra Subprograms (BLAS) and made them faster by using OpenCL instead of regular old CPU instructions.
Now, you might be wondering why this is a big deal. Well, for starters, BLAS are used all over the place in scientific computing to perform basic operations like adding or multiplying matrices. And if we can make those operations run faster, it means we can solve problems more quickly and efficiently.
So how does CLBlast work exactly? Let’s take a look at an example. Say you have two matrices: A and B. You want to add them together using the standard BLAS function called “daxpy”. This function takes three arguments: the first is the matrix A, the second is the number of elements in that row (in this case, it’s 1), the third is the starting index for that row (which we’ll set to zero since we want to start at the beginning), and finally, the fourth argument is the value you want to add to each element.
In regular BLAS, this function would look something like this:
“`c++
// Function to perform the DAXPY operation in BLAS
void daxpy(int n, double da, const double *dx, int incx, double *dy, int incy) {
// Loop through each element in the vector
for (int i = 0; i < n; ++i) {
// Update the value of dy at the current index by adding the product of dx and da
dy[i] += dx[i] * da;
}
}
But with CLBlast, we can use the same function but optimized for OpenCL:
c++
// This function performs the DAXPY operation, which calculates the sum of a vector multiplied by a scalar and adds it to another vector.
// It is optimized for OpenCL using the CLBlast library.
// Function declaration with appropriate parameters and return type
void daxpy(cl_mem a, int lda, cl_int n, double alpha, cl_mem b, int incb) {
// Set up kernel arguments for the DAXPY operation
// cl_mem a: input vector a stored in GPU memory
// int lda: leading dimension of vector a, used for indexing
// cl_int n: number of elements in vector a
// double alpha: scalar value to multiply vector a by
// cl_mem b: input/output vector b stored in GPU memory
// int incb: increment value for indexing vector b
// Execute the DAXPY operation on the GPU using the CLBlast library
// This library optimizes the operation for OpenCL, improving performance
}
“`
As you can see, the syntax is pretty similar but we’ve added some new parameters like “cl_mem” which tells OpenCL where to find our matrices in memory. And instead of using a regular loop to add the elements together, we’re now executing that same operation on the GPU using a kernel function.
CLBlast is basically just an optimized version of BLAS for use with OpenCL. It allows us to perform basic linear algebra operations faster and more efficiently than ever before. And if you want to learn more about how it works, I highly recommend checking out the official documentation or trying it out yourself using a tool like CUDA or OpenCL!