--- layout: stdlib-reference --- # coopVecOuterProductAccumulate ## Description Atomically accumulates the outer product of two cooperative vectors into a matrix. Given an M-element vector a, and an N-element vector b, compute the outer product of a and b, forming a M-row by N-col matrix. The elements in the matrix is then atomically accumulated to memory location represented by matrix. ## Signature

/// Requires Capability Set 1:
void coopVecOuterProductAccumulate<T, int M, int N>(
    CoopVec<T, M> a,
    CoopVec<T, N> b,
    RWByteAddressBuffer matrix,
    int matrixOffset,
    uint matrixStride,
    CoopVecMatrixLayout memoryLayout,
    CoopVecComponentType matrixInterpretation)
    where T : __BuiltinArithmeticType;

/// Requires Capability Set 2:
void coopVecOuterProductAccumulate<T, int M, int N, IgnoredBufferElementType>(
    CoopVec<T, M> a,
    CoopVec<T, N> b,
    RWStructuredBuffer<IgnoredBufferElementType, DefaultDataLayout> matrix,
    int matrixOffset,
    uint matrixStride,
    CoopVecMatrixLayout memoryLayout,
    CoopVecComponentType matrixInterpretation)
    where T : __BuiltinArithmeticType;

/// Requires Capability Set 2:
void coopVecOuterProductAccumulate<T, int M, int N, U, int IgnoredBufferSize>(
    CoopVec<T, M> a,
    CoopVec<T, N> b,
    U[IgnoredBufferSize] matrix,
    int matrixOffset,
    uint matrixStride,
    CoopVecMatrixLayout memoryLayout,
    CoopVecComponentType matrixInterpretation)
    where T : __BuiltinArithmeticType
    where U : __BuiltinArithmeticType;

/// Requires Capability Set 2:
void coopVecOuterProductAccumulate<T, int M, int N>(
    CoopVec<T, M> a,
    CoopVec<T, N> b,
    Ptr<void, Access.ReadWrite, AddressSpace.Device> matrixPtr,
    uint matrixStride,
    CoopVecMatrixLayout memoryLayout,
    CoopVecComponentType matrixInterpretation)
    where T : __BuiltinArithmeticType;

## Generic Parameters #### T: [\_\_BuiltinArithmeticType](../interfaces/0_builtinarithmetictype-029j/index.html) #### M : int #### N : int #### IgnoredBufferElementType #### U: [\_\_BuiltinArithmeticType](../interfaces/0_builtinarithmetictype-029j/index.html) #### IgnoredBufferSize : int ## Parameters #### a : [CoopVec](../types/coopvec-04/index.html)\<[T](../types/coopvec-04/index.html#typeparam-T), M\> The first cooperative vector. #### b : [CoopVec](../types/coopvec-04/index.html)\<[T](../types/coopvec-04/index.html#typeparam-T), [N](../types/coopvec-04/index.html#decl-N)\> The second cooperative vector. #### matrix : [RWByteAddressBuffer](../types/rwbyteaddressbuffer-0126d/index.html) The matrix buffer to accumulate the result into. #### matrixOffset : int Byte offset into the matrix buffer. #### matrixStride : uint The stride between matrix rows/columns in bytes. #### memoryLayout : [CoopVecMatrixLayout](../types/coopvecmatrixlayout-047d/index.html) Specifies the memory layout of the matrix (row-major or column-major). #### matrixInterpretation : [CoopVecComponentType](../types/coopveccomponenttype-047g/index.html) Specifies how to interpret the values in the matrix. #### matrix : [RWStructuredBuffer](../types/rwstructuredbuffer-012c/index.html)\ The matrix buffer to accumulate the result into. #### matrix : [U](coopvecouterproductaccumulate-47cj.html#typeparam-U) \[ [IgnoredBufferSize](coopvecouterproductaccumulate-47cj.html#decl-IgnoredBufferSize) \] The matrix buffer to accumulate the result into. #### matrixPtr : [Ptr](../types/ptr-0/index.html)\ ## Remarks On current hardware, memoryLayout must be TrainingOptimal. When memoryLayout is RowMajor, this function is equivalent to: ``` uint8_t* matrixPtr = matrix + matrixOffset; for (int i = 0; i < M; i++) { for (int j = 0; j < N; j++) { let elem = a[i] * b[j]; atomicAdd(matrixPtr + i * matrixStride + j * sizeof(T), elem); } } ``` ## Availability and Requirements ### Capability Set 1 Defined for the following targets: #### hlsl Available in all stages. #### glsl Available in all stages. #### cpp Available in all stages. #### cuda Available in all stages. Requires capability: `optix_coopvec`. #### spirv Available in all stages. Requires capability: `spvCooperativeVectorNV`. ### Capability Set 2 Defined for the following targets: #### spirv Available in all stages. Requires capability: `spvCooperativeVectorTrainingNV`.