3.3 Dense Vector Data Structure

The psb_T_vect_type data structure encapsulates the dense vectors in a way similar to sparse matrices, i.e. including a base type psb_T_base_vect_type. The user will not, in general, access the vector components directly, but rather via the routines of sec. 6. Among other simple things, we define here an extraction method that can be used to get a full copy of the part of the vector stored on the local process.

The type declaration is shown in figure 3 where T is a placeholder for the data type and precision variants

I

Integer;

S

Single precision real;

D

Double precision real;

C

Single precision complex;

Z

Double precision complex.

The actual data is contained in the polymorphic component v%v; the separation between the application and the actual data is essential for cases where it is necessary to link to data storage made available elsewhere outside the direct control of the compiler/application, e.g. data stored in a graphics accelerator’s private memory.

  type psb_T_base_vect_type
    TYPE(KIND_), allocatable :: v(:)
  end type psb_T_base_vect_type
  type psb_T_vect_type
    class(psb_T_base_vect_type), allocatable :: v
  end type  psb_T_vect_type

3.3.1 Vector Methods

3.3.2 get_nrows — Get number of rows in a dense vector

nr = v%get_nrows()

Type:

Asynchronous.

On Entry

v

the dense vector
Scope: local

On Return

Function value

The number of rows of dense vector v.

3.3.3 sizeof — Get memory occupation in bytes of a dense vector

memory_size = v%sizeof()

Type:

Asynchronous.

On Entry

v

the dense vector
Scope: local

On Return

Function value

The memory occupation in bytes.

3.3.4 set — Set contents of the vector

 call  v%set(alpha[,first,last])
 call  v%set(vect[,first,last])
 call  v%zero()

Type:

Asynchronous.

On Entry

v

the dense vector
Scope: local

alpha

A scalar value.
Scope: local
Type: required
Intent: in.
Specified as: a number of the data type indicated in Table 1.

first,last

Boundaries for setting in the vector.
Scope: local
Type: optional
Intent: in.
Specified as: integers.

vect

An array
Scope: local
Type: required
Intent: in.
Specified as: a number of the data type indicated in Table 1.

Note that a call to v%zero() is provided as a shorthand, but is equivalent to a call to v%set(zero) with the zero constant having the appropriate type and kind.

On Return

v

the dense vector, with updated entries
Scope: local

3.3.5 get_vect — Get a copy of the vector contents

extv = v%get_vect([n])

Type:

Asynchronous.

On Entry

v

the dense vector
Scope: local

n

Size to be returned
Scope: local.
Type: optional; default: entire vector.

On Return

Function value

An allocatable array holding a copy of the dense vector contents. If the argument n is specified, the size of the returned array equals the minimum between n and the internal size of the vector, or 0 if n is negative; otherwise, the size of the array is the same as the internal size of the vector.

3.3.6 clone — Clone current object

call  x%clone(y,info)

Type:

Asynchronous.

On Entry

x

the dense vector.
Scope: local.

On Return

y

A copy of the input object.

info

Return code.