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====== AddSpin ======

###
Matrix.AddSpin($M$) takes a Matrix $M$ that acts on a space with no spin included and returns the matrix doubled in size, where every former entry now splits in spin-up and spin-down. We assume the ordering of the basis alternates between spin up and down. This behaviour is equivalent to calling //[[documentation:language_reference:objects:matrix:functions:Enlarge|Matrix.Enlarge($M$,2)]]//.
###

===== Example =====

==== Input ====
<code Quanty Example.Quanty>
A = Matrix.New({{1,2},{3,4}})
B = Matrix.AddSpin(A)
print(B)
</code>

==== Result ====
<file Quanty_Output>
{ {  1      ,  0      ,  2      ,  0      } ,
  {  0      ,  1      ,  0      ,  2      } ,
  {  3      ,  0      ,  4      ,  0      } ,
  {  0      ,  3      ,  0      ,  4      } }
</file>

===== Table of contents =====
{{indexmenu>..:#2|tsort}}