NAG FL Interface
f06evf (dgthrz)

1 Purpose

2 Specification

3 Description

4 References

5 Arguments

1: $\mathbf{nz}$ – Integer Input

On entry: the number of nonzeros in the compressed sparse vector $x$.

2: $\mathbf{y}\left(*\right)$ – Real (Kind=nag_wp) array Input/Output

Note: the dimension of the array y must be at least ${\displaystyle \underset{\mathit{k}}{\max }}\left\{\mathbf{indx}\left(\mathit{k}\right)\right\}$.

On entry: the vector $y$. Only elements corresponding to indices in indx are accessed.

On exit: the elements of $y$ corresponding to indices in indx are set to zero.

3: $\mathbf{x}\left(*\right)$ – Real (Kind=nag_wp) array Output

Note: the dimension of the array x must be at least $\max (1,\mathbf{nz})$.

On exit: the compressed vector $x$.

4: $\mathbf{indx}\left(*\right)$ – Integer array Input

Note: the dimension of the array indx must be at least $\max (1,\mathbf{nz})$.

On entry: $\mathbf{indx}\left(\mathit{i}\right)$ must contain the index $\mathbf{y}\left(\mathit{i}\right)$, for $\mathit{i}=1,2,\dots ,\mathbf{nz}$, which is to be gathered into $x$.

Constraint: the indices must be distinct.

6 Error Indicators and Warnings

7 Accuracy

8 Parallelism and Performance

9 Further Comments

10 Example