public static NMatrix Dot(this NMatrix A, NMatrix B)
{
/*
* a b c . 0 1 2
* d e f 3 4 5
* 6 7 8
*
* => [a0+b3+c6, a1+b4+c7, a2+b5+c8,
* d0+e3+f6, d1+e4+f7, d2+e5+f8]
*/
if (A.Col != B.Row)
{
return(NMatrix.Empty);
}
uint length = A.Row * B.Col;
double[] array = new double[length];
uint arrIdx = 0;
for (uint i = 0; i < A.Row; i++)
{
for (uint k = 0; k < B.Col; k++)
{
for (uint j = 0; j < A.Col; j++)
{
array[arrIdx] += A[i, j] * B[j, k];
}
arrIdx++;
}
}
var result = new NMatrix(A.Row, B.Col, array);
return(result);
}
public static NMatrix Div(this NMatrix A, double value)
{
if (value == 0)
{
return(NMatrix.Empty);
}
return(Map(A, (elem) => { return elem / value; }));
}
/// <summary>
/// <para>Element-wise functional map function</para>
/// <para>Example) matA.Map((elem) => { return elem * 0.5; });</para>
/// </summary>
/// <param name="A"></param>
/// <param name="func"></param>
/// <returns></returns>
public static NMatrix Map(this NMatrix A, Func <double, double> func)
{
double[] array = new double[A.Row * A.Col];
for (uint i = 0; i < array.Length; i++)
{
array[i] = func.Invoke(A[i]);
}
return(new NMatrix(A.Row, A.Col, array));
}
public NMatrix(NMatrix B)
{
if (B.Invalid)
{
Invalid = true;
}
else
{
Row = B.Row;
Col = B.Col;
RawArray = new double[B.RawArray.Length];
B.RawArray.CopyTo(RawArray, 0);
}
}
/// <summary>
/// <para>Matrix-wise functional map function</para>
/// <para>Example) matA.Map(matB,(elemA, elemB) => { return elemA* elemB; });</para>
/// </summary>
/// <param name="A"></param>
/// <param name="B"></param>
/// <param name="func"></param>
/// <returns></returns>
public static NMatrix Map(this NMatrix A, NMatrix B, Func <double, double, double> func)
{
if (A.Row != B.Row || A.Col != B.Col)
{
return(NMatrix.Empty);
}
uint length = A.Row * A.Col;
double[] array = new double[length];
for (uint i = 0; i < length; i++)
{
array[i] = func.Invoke(A[i], B[i]);
}
return(new NMatrix(A.Row, A.Col, array));
}
public static NMatrix Add(this NMatrix A, NMatrix B)
{
if (A.Row != B.Row || A.Col != B.Col)
{
return(NMatrix.Empty);
}
uint length = A.Row * A.Col;
double[] array = new double[length];
for (uint i = 0; i < length; i++)
{
array[i] = A[i] + B[i];
}
NMatrix matrix = new NMatrix(A.Row, A.Col, array);
return(matrix);
}
public static NMatrix Softmax(NMatrix matrix)
{
var maxElem = matrix.Max();
var expMatrix = matrix.Map(
(elem) => { return(Math.Exp(elem - maxElem)); });
double expSum = 0;
for (uint i = 0; i < expMatrix.Row * expMatrix.Col; i++)
{
expSum += expMatrix[i];
}
var resultMatrix = new NMatrix(expMatrix);
for (uint i = 0; i < resultMatrix.Row * resultMatrix.Col; i++)
{
resultMatrix[i] = expMatrix[i] / expSum;
}
return(resultMatrix);
}
public static NMatrix I(uint size)
{// TODO: Should be optimized
if (size == 0)
{
return(NMatrix.Empty);
}
double[] array = new double[size * size];
for (int i = 0; i < size * size; i++)
{
/*
* 1 0
* 0 1
* 0, 3 (2*2)
*
* 1 0 0
* 0 1 0
* 0 0 1
* 0, 4, 8 (3*3)
*
* 1 0 0 0
* 0 1 0 0
* 0 0 1 0
* 0 0 0 1
* 0, 5, 10, 15 (4*4)
*
* => (idx % (size+1) == 0)
*/
if ((array[i] % (size + 1)) == 0)
{
array[i] = 1;
}
else
{
array[i] = 0;
}
}
var matrix = new NMatrix(size, size, array);
return(matrix);
}
public bool Equals(NMatrix B)
{
// If parameter is null, return false.
if (ReferenceEquals(B, null))
{
return(false);
}
// Optimization for a common success case.
if (ReferenceEquals(this, B))
{
return(true);
}
// If run-time types are not exactly the same, return false.
if (GetType() != B.GetType())
{
return(false);
}
if (Row != B.Row || Col != B.Col ||
Invalid || B.Invalid)
{
return(false);
}
for (uint i = 0; i < (Row * Col); i++)
{
if (this[i] != B[i])
{
return(false);
}
}
return(true);
}
public static NMatrix Mult(this NMatrix A, double value)
{
return(Map(A, (elem) => { return elem * value; }));
}
public static double Sum(this NMatrix A)
{
return(A.RawArray.Sum());
}
public static double Min(this NMatrix A)
{
return(A.RawArray.Min());
}