/// <summary>
/// Applies matrix dot product operation for
/// all matrices in tensors
///
/// O(N^3)
/// </summary>
public static GenTensor <T> TensorMatrixMultiply(GenTensor <T> a,
GenTensor <T> b)
{
#if ALLOW_EXCEPTIONS
if (a.Shape.Count < 2 || b.Shape.Count < 2)
{
throw new InvalidShapeException($"Arguments should be at least matrices while their shapes are {a.Shape} and {b.Shape}");
}
if (a.Shape.SubShape(0, 2) != b.Shape.SubShape(0, 2))
{
throw new InvalidShapeException("Other dimensions of tensors should be equal");
}
#endif
var oldShape = a.Shape.SubShape(0, 2).ToArray();
var newShape = new int[oldShape.Length + 2];
for (int i = 0; i < oldShape.Length; i++)
{
newShape[i] = oldShape[i];
}
newShape[newShape.Length - 2] = a.Shape[a.Shape.Length - 2];
newShape[newShape.Length - 1] = b.Shape[b.Shape.Length - 1];
var resTensor = new GenTensor <T>(newShape);
foreach (var subDimensions in a.IterateOverMatrices())
{
var product = MatrixMultiply(a.GetSubtensor(subDimensions), b.GetSubtensor(subDimensions));
resTensor.SetSubtensor(product, subDimensions);
}
return(resTensor);
}
/// <summary>
/// Creates a tensor whose all matrices are identity matrices
/// 1 is achieved with TWrapper.SetOne()
/// 0 is achieved with TWrapper.SetZero()
/// </summary>
public static GenTensor <T> CreateIdentityTensor(int[] dimensions, int finalMatrixDiag)
{
var newDims = new int[dimensions.Length + 2];
for (int i = 0; i < dimensions.Length; i++)
{
newDims[i] = dimensions[i];
}
newDims[newDims.Length - 2] = newDims[newDims.Length - 1] = finalMatrixDiag;
var res = new GenTensor <T>(newDims);
foreach (var index in res.IterateOverMatrices())
{
var iden = CreateIdentityMatrix(finalMatrixDiag);
res.SetSubtensor(iden, index);
}
return(res);
}
public static GenTensor <T> TensorMatrixDivide(GenTensor <T> a, GenTensor <T> b)
{
#if ALLOW_EXCEPTIONS
InvalidShapeException.NeedTensorSquareMatrix(a);
InvalidShapeException.NeedTensorSquareMatrix(b);
if (a.Shape != b.Shape)
{
throw new InvalidShapeException("Should be of the same shape");
}
#endif
var res = new GenTensor <T>(a.Shape);
foreach (var ind in res.IterateOverMatrices())
{
res.SetSubtensor(
MatrixDivide(
a.GetSubtensor(ind),
b.GetSubtensor(ind)
), ind);
}
return(res);
}
