Creating possible addition of a number
1 Ansicht (letzte 30 Tage)
Ältere Kommentare anzeigen
fyza affandi
am 24 Feb. 2019
Kommentiert: fyza affandi
am 24 Feb. 2019
I have a set of array A
A= [1 2 4 8 16]
For example I want a set of number that make up total of 4 (from A), it would be
B=[1 1 1 1] *total in array B would be 4*
B=[1 1 2]
B=[2 2]
B=[4]
Is it possible to do it in Matlab?
1 Kommentar
Akzeptierte Antwort
John D'Errico
am 24 Feb. 2019
Bearbeitet: John D'Errico
am 24 Feb. 2019
Trivial, if you download my partitions function from the File Exchange.
A = [1 2 4 8 16];
partitions(4,A)
ans =
4 0 0 0 0
2 1 0 0 0
0 2 0 0 0
0 0 1 0 0
Each row of the result tells you how many times that element appears in the target sum.
Find it here:
Note that the number of such partitions can be immense for some problems. You can easily overwhelm such a tool. For example, I have another utiility that will count the number of partitions of an integer.
numberOfPartitions(1000)
ans =
24061467864032622473692149727991
Thus as the sum of numbers in the set [1:1000]. It gets big, and does so pretty fast.
0 Kommentare
Weitere Antworten (1)
Stephen23
am 24 Feb. 2019
Download John D'Errico's excellent partitions:
and use it like this:
>> A = [1,2,4,8,16];
>> M = partitions(4,A);
>> F = @(v)repelem(A,v);
>> C = cellfun(F,num2cell(M,2),'uni',0);
>> C{:}
ans =
1 1 1 1
ans =
1 1 2
ans =
2 2
ans =
4
2 Kommentare
John D'Errico
am 24 Feb. 2019
One of the things I should have added as an option, was the ability to return the partitions in an expanded form, something much like Stephen did here. You can never have too many options in an interface. Well, at least not until you do. ;-)
Siehe auch
Kategorien
Mehr zu Multidimensional Arrays finden Sie in Help Center und File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!