F06GRF (ZDOTUI) (PDF version)
F06 Chapter Contents
F06 Chapter Introduction
NAG Library Manual

NAG Library Routine Document

F06GRF (ZDOTUI)

Note:  before using this routine, please read the Users' Note for your implementation to check the interpretation of bold italicised terms and other implementation-dependent details.

+ Contents

    1  Purpose
    7  Accuracy
    9  Example

1  Purpose

F06GRF (ZDOTUI) computes the scalar product of an unconjugated sparse complex vector with a complex vector.

2  Specification

FUNCTION F06GRF ( NZ, X, INDX, Y)
COMPLEX (KIND=nag_wp) F06GRF
INTEGER  NZ, INDX(*)
COMPLEX (KIND=nag_wp)  X(*), Y(*)
The routine may be called by its BLAS name zdotui.

3  Description

F06GRF (ZDOTUI) returns, via the function name, the value of the scalar product
xTy
where x is a sparse complex vector stored in compressed form, and y is a complex vector in full storage form.

4  References

Dodson D S, Grimes R G and Lewis J G (1991) Sparse extensions to the Fortran basic linear algebra subprograms ACM Trans. Math. Software 17 253–263

5  Parameters

1:     NZ – INTEGERInput
On entry: the number of nonzeros in the sparse vector x.
2:     X(*) – COMPLEX (KIND=nag_wp) arrayInput
Note: the dimension of the array X must be at least max1,NZ .
On entry: the compressed vector x. X contains xi for iJ.
3:     INDX(*) – INTEGER arrayInput
Note: the dimension of the array INDX must be at least max1,NZ .
On entry: INDX must contain the set of indices J.
4:     Y(*) – COMPLEX (KIND=nag_wp) arrayInput
Note: the dimension of the array Y must be at least maxkINDXk .
On entry: the vector y. Only elements corresponding to indices in INDX are accessed.

6  Error Indicators and Warnings

None.

7  Accuracy

Not applicable.

8  Further Comments

None.

9  Example

None.

F06GRF (ZDOTUI) (PDF version)
F06 Chapter Contents
F06 Chapter Introduction
NAG Library Manual

© The Numerical Algorithms Group Ltd, Oxford, UK. 2012