wderiv-library.md

 **UNDER CONSTRUCTION !**
 # Introduction
-This library provides a set of functions for computation derivatives using spectral methods. The lib depends on [FFTW](http://www.fftw.org/) library. The library is compatible with W-SLDA Toolkit however, it can be used as standalone lib. It is written in [C99 standard](https://en.wikipedia.org/wiki/C99).
+This library provides a set of functions for computation derivatives using spectral methods. The lib depends on [FFTW](http://www.fftw.org/) library. The library is compatible with W-SLDA Toolkit however, it can be used as standalone lib. It is written in [C99 standard](https://en.wikipedia.org/wiki/C99).
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+
+# Name convention 
+
+Generic name of a function is `wderiv_operation_xd_t`, where:
+* `wderiv`: fixed, function belongs to _wderiv_ lib,
+* `operation`:  
+  * dfdx
+  * dfdy
+  * d2fdx2
+  * laplace
+  * grad
+  * ...
+* `x`:
+  * `1` for 1D problems
+  * `2` for 2D problems
+  * `3` for 3D problems
+* `t`:
+  * `r` for real problems