# cumsum

cumulative sum of array elements

### Syntax

y=cumsum(x) y=cumsum(x,orientation) y=cumsum(x,outtype) y=cumsum(x,orientation,outtype)

### Arguments

- x
an array of reals, complex, booleans, polynomials or rational fractions.

- orientation
This argument can be

either a string with possible values

`"*"`

,`"r"`

,`"c"`

or`"m"`

or a number with positive integer value

- outtype
a string with possible values

`"native"`

or`"double"`

.- y
scalar or array

### Description

Returns the cumulative sum of array elements.
For an array x, `y=cumsum(x)`

a matrix y of the same size as x.
The value `y(i)`

is the sum of all elements of `x(1:i)`

*i.e.*:

`y=cumsum(x,orientation)`

returns in y the cumulative sum of x along the dimension given by orientation:

if orientation is equal to 1 or "r" then:

or

if orientation is equal to 2 or "c" then:

or

if orientation is equal to n then:

`y=cumsum(x,"*")`

is equivalent to`y=cumsum(x)`

`y=cumsum(x,"m")`

is equivalent to`y=cumsum(x,orientation)`

where orientation is the index of the first dimension of x that is greater than 1. This option is used for Matlab compatibility.

The outtype argument rules the way the summation is done:

For arrays of floats, of polynomials, of rational fractions, the evaluation is always done using floating points computations. The

`"double"`

or`"native"`

options are equivalent.For arrays of integers,

if

`outtype="native"`

the evaluation is done using integer computations (modulo 2^b, where b is the number of bits used),if

`outtype="double"`

the evaluation is done using floating point computations.The default value is

`outtype="native"`

.For arrays of booleans,

if

`outtype="native"`

the evaluation is done using boolean computations ( + is replaced by |),if

`outtype="double"`

the evaluation is done using floating point computations (%t values are replaced by 1 and %f values by 0).The default value is

`outtype="double"`

.

This function applies, with identical rules to sparse matrices. |

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