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# VecMTDot
Computes indefinite vector multiple dot products. That is, it does NOT use the complex conjugate.
## Synopsis
```
#include "petscvec.h"
PetscErrorCode VecMTDot(Vec x, PetscInt nv, const Vec y[], PetscScalar val[])
```
Collective
## Input Parameters
- ***x -*** one vector
- ***nv -*** number of vectors
- ***y -*** array of vectors. Note that vectors are pointers
## Output Parameter
- ***val -*** array of the dot products
## Notes for Users of Complex Numbers
For complex vectors, `VecMTDot()` computes the indefinite form
```none
val = (x,y) = y^T x,
```
where y^T denotes the transpose of y.
Use `VecMDot()` for the inner product
```none
val = (x,y) = y^H x,
```
where y^H denotes the conjugate transpose of y.
## See Also
[](ch_vectors), `Vec`, `VecMDot()`, `VecTDot()`
## Level
intermediate
## Location
src/vec/vec/interface/rvector.c
## Implementations
VecMTDot_MPIKokkos in src/vec/vec/impls/mpi/kokkos/mpikok.kokkos.cxx
VecMTDot_MPI in src/vec/vec/impls/mpi/pvec2.c
VecMTDot_Nest in src/vec/vec/impls/nest/vecnest.c
VecMTDot_Seq in src/vec/vec/impls/seq/dvec2.c
VecMTDot_SeqKokkos in src/vec/vec/impls/seq/kokkos/veckok.kokkos.cxx
VecMTDot_SeqViennaCL in src/vec/vec/impls/seq/seqviennacl/vecviennacl.cxx
---
[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/src/vec/vec/interface/rvector.c)
[Index of all Vec routines](index.md)
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[Index of all manual pages](/manualpages/singleindex.md)