Wolfram Language Paclet Repository
Community-contributed installable additions to the Wolfram Language
PeterBurbery`Combinatorics`
FindDescentElements |
|
| | ||||
Details and Options
Examples
(3)
Basic Examples
(1)
Consider this random permutation.
In[1]:=
randomPermutation=RandomSample[Range[9]]
Out[1]=
{9,1,3,4,7,5,8,6,2}
Find the positions, that is the indices, of the descent. An index i is an descent index if >.
a
i
a
i+1
In[2]:=
 | FindDescentElements |
Out[2]=
{{9,1},{7,5},{8,6},{6,2}}
Find the descents.
In[3]:=
| FindDescentElements |
Out[3]=
{{9,1},{7,5},{8,6},{6,2}}
Write this with Inactive.
In[4]:=
Inactive[Greater]@@@
[randomPermutation]
| FindDescentElements |
Out[4]=
{9>1,7>5,8>6,6>2}
Are all these statements true?
In[5]:=
AllTrue[Activate[#]&]Inactive[Greater]@@@
[randomPermutation]
| FindDescentElements |
Out[5]=
True
Reverse with less:
In[6]:=
Inactive[Less]@@@Map[Reverse]
[randomPermutation]
| FindDescentElements |
Out[6]=
{1<9,5<7,6<8,2<6}
Are all these statements true?
In[7]:=
AllTrue[Activate[#]&]Inactive[Less]@@@Map[Reverse]
[randomPermutation]
| FindDescentElements |
Out[7]=
True
Scope
(1)
Options
(1)
 |
|
""