Undoubtedly, MATLAB is the best and most popular software tool for high end mathematical computations. However, there are many other good alternatives to MATLAB which are sufficient for academic/educational purpose. The reason why alternatives to MATLAB are considered is that it is too costly for an individual to buy MATLAB. Although the student version is available, it also costs more than ₹50,000. Other reasons are that there are some special features in other softwares that MATLAB doesn't.

Here is the list and a short review of a few recommended MATLAB alternatives.
There are many softwares that can be used for high end computing instead of MATLAB. But here I am listing softwares that have code compatibility with MATLAB, keeping students in mind as many university syllabi prefers MATLAB and also do have courses based on it.