# naginterfaces.library.dot.complex_​prec¶

naginterfaces.library.dot.complex_prec(a, b, cx, sw)[source]

complex_prec calculates the value of a complex scalar product using basic precision or additional precision and adds it to a complex initial value.

For full information please refer to the NAG Library document for x03ab

https://www.nag.com/numeric/nl/nagdoc_27.3/flhtml/x03/x03abf.html

Parameters
acomplex, array-like, shape

The elements of the first vector.

bcomplex, array-like, shape

The elements of the second vector.

cxcomplex

The initial value .

swbool

The precision to be used in the calculation.

basic precision.

Returns
dxcomplex

The result .

Raises
NagValueError
(errno )

On entry, .

Constraint: .

(errno )

On entry, .

Constraint: .

(errno )

On entry, , and .

Constraint: .

(errno )

On entry, , and .

Constraint: .

Notes

No equivalent traditional C interface for this routine exists in the NAG Library.

complex_prec calculates the scalar product of two complex vectors and adds it to an initial value to give a correctly rounded result :

If , .

The vector elements and are stored in selected elements of the one-dimensional array arguments and .

The products are accumulated in basic precision or additional precision depending on the argument .

This function has been designed primarily for use as an auxiliary function by other functions in the NAG Library, especially those in the modules on Linear Algebra.