BLAS is an API, more or less.<p><a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Basic_Linear_Algebra_Subprograms#Implementations" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Basic_Linear_Algebra_Subprogra...</a>