Code optimization using Splice

Some information is given here to explain how Splice can be used in conjunction with Optimize to automate code generation. Specifically, it is necessary to keep track of the number of optimization variables introduced during the optimization process, in order to make appropriate type and dimension declarations.

In FORTRAN, it is possible to declare all optimization variables to be the same type by using implicit statement declarations as mentioned previously. In C this is not possible and there are several strategies which may be adopted, the simplest of which is outlined below.

• Use the option OptimizeFormat->False. This has the effect of generating the optimization variables in array form o[i] (the default is a concatenated format oi which is more memory efficient). This is facilitated by a finishing touch during formatting, where optimization variables are returned in consecutively numbered form o[1], o[2],....
• It is difficult to judge in advance exactly how many optimizations will be performed. Optimize returns a list of the form {optseq,optexpr}. The dimension of the optimization array corresponds to Length[optseq].
• Use a two-pass Splice. The first pass fills in the body of the procedure and contains statements such as o(ToExpression["<* arraydim *>"]). The second pass is used to fill in the array dimension arraydim.