Symbolic cumulative sum
Create a vector and find the cumulative sum of its elements.
V = 1./factorial(sym([1:5])) sum_V = cumsum(V)
V = [ 1, 1/2, 1/6, 1/24, 1/120] sum_V = [ 1, 3/2, 5/3, 41/24, 103/60]
Create matrix a 4-by-4 symbolic matrix A
all
elements of which equal 1.
A = sym(ones(4,4))
A = [ 1, 1, 1, 1] [ 1, 1, 1, 1] [ 1, 1, 1, 1] [ 1, 1, 1, 1]
Compute the cumulative sum of elements of A
.
By default, cumsum
returns the cumulative sum
of each column.
sumA = cumsum(A)
sumA = [ 1, 1, 1, 1] [ 2, 2, 2, 2] [ 3, 3, 3, 3] [ 4, 4, 4, 4]
Create matrix a 4-by-4 symbolic matrix A
all
elements of which equal 1.
A = sym(ones(4,4))
A = [ 1, 1, 1, 1] [ 1, 1, 1, 1] [ 1, 1, 1, 1] [ 1, 1, 1, 1]
Compute the cumulative sum of each row of the matrix A
.
sumA = cumsum(A,2)
sumA = [ 1, 2, 3, 4] [ 1, 2, 3, 4] [ 1, 2, 3, 4] [ 1, 2, 3, 4]
Create matrix a 4-by-4 symbolic matrix, all elements of which equal 1.
A = sym(ones(4,4))
A = [ 1, 1, 1, 1] [ 1, 1, 1, 1] [ 1, 1, 1, 1] [ 1, 1, 1, 1]
Calculate the cumulative sum along the columns in both directions.
Specify the 'reverse'
option to work from right
to left in each row.
columnsDirect = cumsum(A) columnsReverse = cumsum(A,'reverse')
columnsDirect = [ 1, 1, 1, 1] [ 2, 2, 2, 2] [ 3, 3, 3, 3] [ 4, 4, 4, 4] columnsReverse = [ 4, 4, 4, 4] [ 3, 3, 3, 3] [ 2, 2, 2, 2] [ 1, 1, 1, 1]
Calculate the cumulative sum along the rows in both directions.
Specify the 'reverse'
option to work from right
to left in each row.
rowsDirect = cumsum(A,2) rowsReverse = cumsum(A,2,'reverse')
rowsDirect = [ 1, 2, 3, 4] [ 1, 2, 3, 4] [ 1, 2, 3, 4] [ 1, 2, 3, 4] rowsReverse = [ 4, 3, 2, 1] [ 4, 3, 2, 1] [ 4, 3, 2, 1] [ 4, 3, 2, 1]