# sum

sum of array elements

### Syntax

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

### Arguments

- x
- Array of booleans (full or sparse), encoded integers, real or complex numbers (full or sparse), polynomials, or rationals.
- orientation
- it can be either
- a character
`"*"`

(default),`"r"`

,`"c"`

or`"m"`

- a positive integer: Index of the dimension along which the sums must be computed.

- a character
- outtype
- string
`"native"`

or`"double"`

. - y
- scalar or array

### Description

For an array `x`

,
`y=sum(x)`

returns in the scalar `y`

the
sum of all the elements of `x`

.

`y=sum(x,orientation)`

returns in
`y`

the sum of `x`

along the
dimension given by `orientation`

:

if

`orientation`

is equal to 1 or "r" thenor

if

`orientation`

is equal to 2 or "c" then:or

if

`orientation`

is equal to n then`y=sum(x,"*")`

is equivalent to`y=sum(x)`

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

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

where`orientation`

is the index of the first dimension of`x`

that is greater than 1.

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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