Update README.md

Author: perazz

README.md

@@ -1,5 +1,5 @@
 # fortran-lapack
-This package provides precision-agnostig, high-level linear algebra APIs for `real` and `complex` arguments in Modern Fortran. The APIs are similar to NumPy/SciPy operations, and leverage a Modern Fortran implementation of the [Reference-LAPACK](http://github.com/reference-LAPACK) library.
+This package provides precision-agnostic, high-level linear algebra APIs for `real` and `complex` arguments in Modern Fortran. The APIs are similar to NumPy/SciPy operations, and leverage a Modern Fortran implementation of the [Reference-LAPACK](http://github.com/reference-LAPACK) library.
 
 # Current API
 Procedure   | Type | Description | Optional arguments
@@ -54,6 +54,14 @@ To add fortran-lapack to your project, simply add it as a dependency:
 [dependencies]
 fortran-lapack = { git="https://github.com/perazz/fortran-lapack.git" }
 ```
+
+`fortran-lapack` is compatible with the LAPACK API. If high-performance external BLAS/LAPACK libraries are available, it is sufficient to define macros
+
+```
+[dependencies]
+fortran-lapack = { git="https://github.com/perazz/fortran-lapack.git", preprocess.cpp.macros=["LA_EXTERNAL_BLAS", "LA_EXTERNAL_LAPACK"] }
+```
+
 # Extension to external BLAS/LAPACK libraries
 
 Generic interfaces to most BLAS/LAPACK functions are exposed to modules `la_blas` and `la_lapack`. These interfaces drop the initial letter to wrap a precision-agnostic version. For example, `axpy` is a precision-agnostic interface to `saxpy`, `daxpy`, `caxpy`, `zaxpy`, `qaxpy`, `waxpy`.