Finally, C is slow. Yeah, you read that right. Its main problem is that it has no non-wizardry high level semantics for parallelism. Do you know about openMP?

Finally, C is slow. Yeah, you read that right. Its main problem is that it has no non-wizardry high level semantics for parallelism. Do you know about openMP? Which works in most mainstream c compilers (clang, gcc, icc, msvs, etc). Ok, its not part of the standard, but IMHO thats probably a good thing. C doesn't dictate a paradigm which allows it to support a wide range of competing standards. Pick the one best for your project, or embed something like openCL or lua right into your C project. Of course the opposite can be said as well, write your code in python/whatever and then write a C plugin for the critical portions. Because, outside of fortran or C++ pretty much nothing comes close to the capability of C to solve a problem quickly. Which if no one noticed is even more important these days than it was two decades ago, when companies used crappy languages and shipped products that wasted 99% of the cycles of the users computer. Today doubling the performance of your product can literally 1/2 the computing costs at your friendly cloud provider/datacenter.