Functional programming languages are free of side effects which makes programs written in them easy to verify, parallelize and optimize. However, to maintain this model, naive execution may involve an excessive amount of copying which consumes both space and time. Optimizing the compilers for such languages with an algorithm that minimizes copies improves their performance without losing the side effect free feature. In this thesis we present a O ( TlogT + V E w + V 2 ) greedy in-placeness algorithm that reduces the amount of copying in such languages. We have implemented a prototype of the in-placeness algorithm for the widely used graphical programming language LabVIEW and compared its performance to the performance of the ad-hoc in-placeness heuristic used in the current LabVIEW compiler. Our in-placeness algorithm achieves promising improvements to LabVIEW performance in a uniform and systematic approach. National Instruments anticipates incorporating our algorithm in the next published version of the LabVIEW compiler.