---
name: "MPI_Type_vector.openmpi"
section: "3"
platform: "linux"
package: "openmpi-doc"
version: "5.0.7-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/MPI_Type_vector.openmpi"
---

# MPI\_Type\_vector.openmpi(3)

*MPI\_Type\_vector* — Creates a vector (strided) datatype.

## SYNTAX

### C Syntax

```
#include <mpi.h>
int MPI_Type_vector(int count, int blocklength, int stride,
     MPI_Datatype oldtype, MPI_Datatype *newtype)
```

### Fortran Syntax

```
USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_TYPE_VECTOR(COUNT, BLOCKLENGTH, STRIDE, OLDTYPE, NEWTYPE,
             IERROR)
     INTEGER COUNT, BLOCKLENGTH, STRIDE, OLDTYPE
     INTEGER NEWTYPE, IERROR
```

### Fortran 2008 Syntax

```
USE mpi_f08
MPI_Type_vector(count, blocklength, stride, oldtype, newtype, ierror)
     INTEGER, INTENT(IN) :: count, blocklength, stride
     TYPE(MPI_Datatype), INTENT(IN) :: oldtype
     TYPE(MPI_Datatype), INTENT(OUT) :: newtype
     INTEGER, OPTIONAL, INTENT(OUT) :: ierror
```

## INPUT PARAMETERS

- •

  **count**: Number of blocks (nonnegative integer).

- •

  **blocklength**: Number of elements in each block (nonnegative integer).

- •

  **stride**: Number of elements between start of each block (integer).

- •

  **oldtype**: Old datatype (handle).

## OUTPUT PARAMETERS

- •

  **newtype**: New datatype (handle).

- •

  **ierror**: Fortran only: Error status (integer).

## DESCRIPTION

The function *MPI\_Type\_vector* is a general constructor that allows replication of a datatype into locations that consist of equally spaced blocks. Each block is obtained by concatenating the same number of copies of the old datatype. The spacing between blocks is a multiple of the extent of the old datatype.

**Example 1:** Assume, again, that oldtype has type map {(double, 0), (char, 8)}, with extent 16. A call to MPI\_Type\_vector(2, 3, 4, oldtype, newtype) will create the datatype with type map

```
{(double, 0), (char, 8), (double, 16), (char, 24),
(double, 32), (char, 40),
(double, 64), (char, 72),
(double, 80), (char, 88), (double, 96), (char, 104)}
```

That is, two blocks with three copies each of the old type, with a stride of 4 elements (4 x 16 bytes) between the blocks.

**Example 2:** A call to MPI\_Type\_vector(3, 1, -2, oldtype, newtype) will create the datatype

```
{(double, 0), (char, 8), (double, -32), (char, -24),
(double, -64), (char, -56)}
```

In general, assume that oldtype has type map

```
{(type(0), disp(0)), ..., (type(n-1), disp(n-1))},
```

with extent ex. Let bl be the blocklength. The newly created datatype has a type map with count x bl x n entries:

```
{(type(0), disp(0)), ..., (type(n-1), disp(n-1)),
(type(0), disp(0) + ex), ..., (type(n-1), disp(n-1) + ex), ...,
(type(0), disp(0) + (bl -1) * ex),...,
(type(n-1), disp(n-1) + (bl -1)* ex),
(type(0), disp(0) + stride * ex),..., (type(n-1),
disp(n-1) + stride * ex), ...,
(type(0), disp(0) + (stride + bl - 1) * ex), ...,
(type(n-1), disp(n-1) + (stride + bl -1) * ex), ...,
(type(0), disp(0) + stride * (count -1) * ex), ...,
(type(n-1), disp(n-1) + stride * (count -1) * ex), ...,
(type(0), disp(0) + (stride * (count -1) + bl -1) * ex), ...,
(type(n-1), disp(n-1) + (stride * (count -1) + bl -1) * ex)}
```

A call to MPI\_Type\_contiguous(count, oldtype, newtype) is equivalent to a call to MPI\_Type\_vector(count, 1, 1, oldtype, newtype), or to a call to MPI\_Type\_vector(1, count, n, oldtype, newtype), n arbitrary.

## ERRORS

Almost all MPI routines return an error value; C routines as the return result of the function and Fortran routines in the last argument.

Before the error value is returned, the current MPI error handler associated with the communication object (e.g., communicator, window, file) is called. If no communication object is associated with the MPI call, then the call is considered attached to MPI\_COMM\_SELF and will call the associated MPI error handler. When MPI\_COMM\_SELF is not initialized (i.e., before *MPI\_Init*/*MPI\_Init\_thread*, after *MPI\_Finalize*, or when using the Sessions Model exclusively) the error raises the initial error handler. The initial error handler can be changed by calling *MPI\_Comm\_set\_errhandler* on MPI\_COMM\_SELF when using the World model, or the mpi\_initial\_errhandler CLI argument to mpiexec or info key to *MPI\_Comm\_spawn*/*MPI\_Comm\_spawn\_multiple*. If no other appropriate error handler has been set, then the MPI\_ERRORS\_RETURN error handler is called for MPI I/O functions and the MPI\_ERRORS\_ABORT error handler is called for all other MPI functions.

Open MPI includes three predefined error handlers that can be used:

- •

  **MPI\_ERRORS\_ARE\_FATAL** Causes the program to abort all connected MPI processes.

- •

  **MPI\_ERRORS\_ABORT** An error handler that can be invoked on a communicator, window, file, or session. When called on a communicator, it acts as if *MPI\_Abort* was called on that communicator. If called on a window or file, acts as if *MPI\_Abort* was called on a communicator containing the group of processes in the corresponding window or file. If called on a session, aborts only the local process.

- •

  **MPI\_ERRORS\_RETURN** Returns an error code to the application.

MPI applications can also implement their own error handlers by calling:

- •

  *MPI\_Comm\_create\_errhandler* then *MPI\_Comm\_set\_errhandler*

- •

  *MPI\_File\_create\_errhandler* then *MPI\_File\_set\_errhandler*

- •

  *MPI\_Session\_create\_errhandler* then *MPI\_Session\_set\_errhandler* or at *MPI\_Session\_init*

- •

  *MPI\_Win\_create\_errhandler* then *MPI\_Win\_set\_errhandler*

Note that MPI does not guarantee that an MPI program can continue past an error.

See the *MPI man page* for a full list of *MPI error codes*.

See the Error Handling section of the MPI-3.1 standard for more information.

**SEE ALSO:**

- •

  *MPI\_Type\_create\_hvector*

- •

  *MPI\_Type\_hvector*

## COPYRIGHT

2003-2025, The Open MPI Community