Add note in Faust/concatenation doc about use of LazyLinearOp to encapsulate a Faust.

Issue #267.

wrapper/matlab/+matfaust/@Faust/Faust.m

@@ -75,6 +75,10 @@
 %> Mainly for convenience and test purposes, a Faust can be converted into
 %> the corresponding full matrix using the function Faust.full.
 %>
+%> @note it could be wiser to encapsulate a Faust in a
+%> <a href="https://gitlab.inria.fr/faustgrp/matlazylinop/-/blob/main/src/%2Blazylinop/aslazylinearoperator.m">lazylinop.LazyLinearOp</a>
+%> for a totally lazy paradigm on all available operations.
+%>
 %> @warning using Faust.full is discouraged except for test purposes, as it
 %> loses the main potential interests of the FAuST structure: compressed
 %> memory storage and faster matrix-vector multiplication compared to its
@@ -2824,6 +2828,11 @@ classdef Faust < handle % subclass of handle for Faust.delete to be called on cl
 		%>
 		%> @retval C the concatenation result as a new Faust.
 		%>
+		%> @note it could be wiser to encapsulate a Faust in a
+		%> <a href="https://gitlab.inria.fr/faustgrp/matlazylinop/-/blob/main/src/%2Blazylinop/aslazylinearoperator.m">lazylinop.LazyLinearOp</a>
+		%> for a lazy concatenation.
+		%> </br>
+		%>
 		%>
 		%> @b Example
 		%> @code
@@ -2960,7 +2969,11 @@ classdef Faust < handle % subclass of handle for Faust.delete to be called on cl
 		%>
 		%> &nbsp;&nbsp;&nbsp; @b C=HORZCAT(F,A) concatenates the Faust F and A horizontally. A is a Faust or a sparse/full matrix. The result is the Faust C. @b HORZCAT(F,A) is the same as [F,G].<br/>
 		%> &nbsp;&nbsp;&nbsp; @b C=HORZCAT(@b F,@b A,@b B,…) concatenates horizontally F to A, B, etc. @b HORZCAT(@b F,@b A, @b B,…) is the same as [F,A,B,…].<br/>
-%>
+		%>
+		%> @note it could be wiser to encapsulate a Faust in a
+		%> <a href="https://gitlab.inria.fr/faustgrp/matlazylinop/-/blob/main/src/%2Blazylinop/aslazylinearoperator.m">lazylinop.LazyLinearOp</a>
+		%> for a lazy concatenation.
+		%>
 		%> <p>@b See @b also Faust.vertcat, Faust.cat.
 		%======================================================================
 		function HC = horzcat(varargin)
@@ -2980,6 +2993,10 @@ classdef Faust < handle % subclass of handle for Faust.delete to be called on cl
 		%> &nbsp;&nbsp;&nbsp; @b C=VERTCAT(F,A) concatenates the Faust F and A vertically. A is a Faust or a sparse/full matrix. The result is the Faust C. @b VERTCAT(F,A) is the same as [F;G].<br/>
 		%> &nbsp;&nbsp;&nbsp; @b C=VERTCAT(@b F, @b A, @b B,…) concatenates vertically F to A, B etc. @b VERTCAT(@b F, @b A, @b B,…) is the same as [F;A;B;…].<br/>
 		%>
+		%> @note it could be wiser to encapsulate a Faust in a
+		%> <a href="https://gitlab.inria.fr/faustgrp/matlazylinop/-/blob/main/src/%2Blazylinop/aslazylinearoperator.m">lazylinop.LazyLinearOp</a>
+		%> for a lazy concatenation.
+		%>
 		%> <p>@b See @b also Faust.horzcat, Faust.cat.
 		%======================================================================
 		function VC = vertcat(varargin)

wrapper/python/pyfaust.py

@@ -71,6 +71,10 @@ class Faust(numpy.lib.mixins.NDArrayOperatorsMixin):
     Mainly for convenience and test purposes, a Faust can be converted into
     the corresponding full matrix using the function Faust.toarray.
 
+    NOTE: it could be wiser to encapsulate a Faust in a
+    <a href="https://faustgrp.gitlabpages.inria.fr/lazylinop/api_lazylinop.html#lazylinop.aslazylinearoperator">lazylinop.LazyLinearOp</a>
+    for a totally lazy paradigm on all available operations.
+
     Warning: using Faust.toarray is discouraged except for test purposes, as it
     loses the main potential interests of the FAuST structure: compressed
     memory storage and faster matrix-vector multiplication compared to its
@@ -1388,6 +1392,10 @@ class Faust(numpy.lib.mixins.NDArrayOperatorsMixin):
         <br/>N.B.: you could have an elementwise non-significant absolute
         difference between the two members.
 
+        NOTE: it could be wiser to encapsulate a Faust in a
+        <a href="https://faustgrp.gitlabpages.inria.fr/lazylinop/api_lazylinop.html#lazylinop.aslazylinearoperator">lazylinop.LazyLinearOp</a>
+        for a lazy concatenation.
+
 
            Args:
                F: the Faust to concatenate to.
@@ -3367,7 +3375,7 @@ def concatenate(_tuple, *args, axis=0, **kwargs):
         - FACTOR 4 (double) SPARSE, size 56x100, density 0.05, nnz 280
         - FACTOR 5 (double) SPARSE, size 100x50, density 0.02, nnz 100
 
-    <b>See also</b> numpy.concatenate
+    <b>See also</b> numpy.concatenate, Faust.concatenate
     """
     if not isinstance(_tuple, tuple):
         raise TypeError("first arg must be a tuple")
@@ -3395,6 +3403,11 @@ def hstack(_tuple):
 
     <b>See also</b> numpy.hstack
 
+
+    NOTE: it could be wiser to encapsulate a Faust in a
+    <a href="https://faustgrp.gitlabpages.inria.fr/lazylinop/api_lazylinop.html#lazylinop.aslazylinearoperator">lazylinop.LazyLinearOp</a>
+    for a lazy concatenation.
+
     Example:
         >>> from pyfaust import *
         >>> seed(42) # just for reproducibility
@@ -3417,6 +3430,11 @@ def vstack(_tuple):
 
     <b>See also</b> numpy.vstack
 
+
+    NOTE: it could be wiser to encapsulate a Faust in a
+    <a href="https://faustgrp.gitlabpages.inria.fr/lazylinop/api_lazylinop.html#lazylinop.aslazylinearoperator">lazylinop.LazyLinearOp</a>
+    for a lazy concatenation.
+
     Example:
         >>> from pyfaust import *
         >>> seed(42) # just for reproducibility