Automatic vectorization, in parallel computing, is a special case of automatic parallelization, where a computer program is converted from a scalar implementation, which processes a single pair of operands at a time, to a vector implementation, which processes one operation on multiple pairs of operands at once. For example, modern conventional computers, including specialized supercomputers, typically have vector operations that simultaneously perform operations such as the following four additions:

However, in most programming languages one typically writes loops that sequentially perform additions of many numbers. Here is an example of such a loop, written in C: <source lang="c"> for (i=0; i<n; i++)

   c[i] = a[i] + b[i];

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