/// <summary>
/// Return a new array of given shape and type, filled with ones.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="np"></param>
/// <param name="shape"></param>
/// <returns></returns>
public static NDArray ones(Shape shape, Type dtype = null)
{
if (dtype == null)
{
dtype = typeof(double);
}
var nd = new NDArray(dtype, shape);
switch (dtype.Name)
{
case "Int32":
nd.SetData(Enumerable.Range(0, nd.size).Select(x => 1).ToArray());
break;
case "Double":
nd.SetData(Enumerable.Range(0, nd.size).Select(x => 1.0).ToArray());
break;
case "Boolean":
nd.SetData(Enumerable.Range(0, nd.size).Select(x => true).ToArray());
break;
}
return(nd);
}
public static NDArray asanyarray <T>(T data) where T : struct
{
var nd = new NDArray(typeof(T), new int[0]);
nd.SetData(new T[] { data });
return(nd);
}
public NDArray randint(int low, int?high = null, Shape shape = null)
{
var rng = new Random();
if (high == null)
{
high = int.MaxValue;
}
if (shape == null)
{
shape = new Shape(high.Value - low);
}
var data = new int[shape.Size];
for (int i = 0; i < data.Length; i++)
{
data[i] = rng.Next(low, high.Value);
}
var np = new NDArray(typeof(int), shape.Dimensions.ToArray());
np.SetData(data);
return(np);
}
public static NDArray asanyarray <T>(T[] data, int ndim = 1) where T : struct
{
var nd = new NDArray(typeof(T), data.Length);
nd.SetData(data);
return(nd);
}
/// <summary>
/// Draw samples from a uniform distribution.
/// Samples are uniformly distributed over the half-open interval [low, high) (includes low, but excludes high). In other words, any value within the given interval is equally likely to be drawn by uniform.
/// </summary>
/// <param name="low">Lower boundary of the output interval. All values generated will be greater than or equal to low. The default value is 0.</param>
/// <param name="high">Upper boundary of the output interval. All values generated will be less than high. The default value is 1.0.</param>
/// <param name="size">Output shape. If the given shape is, e.g., m, n, k, then m * n * k samples are drawn. If size is None (default), a single value is returned if low and high are both scalars. </param>
/// <returns>NDArray with values of type <see cref="double"/></returns>
public NDArray uniform(double low, double high, params int[] size)
{
if (size == null || size.Length == 0) //return scalar
{
var ret = new NDArray <double>(new Shape(1));
var data = new double[] { low + randomizer.NextDouble() * (high - low) };
ret.SetData(data);
return(ret);
}
var result = new NDArray <double>(size);
double[] resultArray = result.Data <double>();
//parallelism is prohibited to make sure the result come out presistant
double diff = high - low;
for (int i = 0; i < result.size; ++i)
{
resultArray[i] = low + randomizer.NextDouble() * diff;
}
result.SetData(resultArray); //incase of a view
return(result);
}
public static NDArray asanyarray(string data)
{
var nd = new NDArray(typeof(string), new int[0]);
nd.SetData(new string[] { data });
return(nd);
}
public static NDArray asanyarray(string[] data, int ndim = 1)
{
var nd = new NDArray(typeof(string), data.Length);
nd.SetData(data);
return(nd);
}
public static NDArray ravel(matrix mx)
{
var nd = new NDArray(mx.dtype, mx.size);
switch (mx.dtype.Name)
{
case "Double":
nd.SetData(mx.Data <double>());
break;
case "Int32":
nd.SetData(mx.Data <int>());
break;
}
return(nd);
}
/// <summary>
/// Random values in a given shape.
/// Create an array of the given shape and populate it with random samples from a uniform distribution over [0, 1).
/// </summary>
public NDArray rand(Shape shape)
{
NDArray ndArray = new NDArray(typeof(double), shape);
double[] numArray = ndArray.Data <double>();
for (int index = 0; index < ndArray.size; ++index)
{
numArray[index] = randomizer.NextDouble();
}
ndArray.SetData <double[]>(numArray);
return(ndArray);
}
public static NDArray array <T>(T[,] data)
{
var nd = new NDArray(typeof(T), new Shape(data.GetLength(0), data.GetLength(1)));
for (int dim0 = 0; dim0 < data.GetLength(0); dim0++)
{
for (int dim1 = 0; dim1 < data.GetLength(1); dim1++)
{
nd.SetData(data[dim0, dim1], dim0, dim1);
}
}
return(nd);
}
/*public static NDArray array(System.Drawing.Bitmap image)
* {
* var imageArray = new NDArray(typeof(Byte));
*
* var bmpd = image.LockBits(new System.Drawing.Rectangle(0, 0, image.Width, image.Height), System.Drawing.Imaging.ImageLockMode.ReadOnly, image.PixelFormat);
* var dataSize = bmpd.Stride * bmpd.Height;
*
* var bytes = new byte[dataSize];
* System.Runtime.InteropServices.Marshal.Copy(bmpd.Scan0, bytes, 0, dataSize);
* image.UnlockBits(bmpd);
*
* imageArray.Storage.Allocate(typeof(byte),new Shape(bmpd.Height, bmpd.Width, System.Drawing.Image.GetPixelFormatSize(image.PixelFormat) / 8),1);
* imageArray.Storage.SetData(bytes);
*
* return imageArray;
* }*/
public static NDArray array <T>(T[][] data)
{
var nd = new NDArray(typeof(T), new Shape(data.Length, data[0].Length));
for (int row = 0; row < data.Length; row++)
{
for (int col = 0; col < data[row].Length; col++)
{
nd.SetData(data[row][col], row, col);
}
}
return(nd);
}
public NDArray randint(int low, int size = 1)
{
var data = new int[size];
for (int i = 0; i < data.Length; i++)
{
data[i] = randomizer.Next(low, int.MaxValue);
}
var np = new NDArray(typeof(int), size);
np.SetData(data);
return(np);
}
private NDArray setValue2D <T>(NDArray indexes)
{
var buf = Data <T>();
var idx = indexes.Data <int>();
var nd = new NDArray(dtype, new Shape(indexes.size, shape[1]));
Parallel.For(0, nd.shape[0], (row) =>
{
for (int col = 0; col < nd.shape[1]; col++)
{
nd.SetData(buf[Storage.Shape.GetIndexInShape(idx[row], col)], row, col);
}
});
return(nd);
}
private NDArray setValue2D <T>(NDArray indexes)
{
var buf = Data <T>();
var idx = indexes.Data <int>();
var selectedValues = new NDArray(dtype, new Shape(indexes.size, shape[1]));
Parallel.ForEach(Enumerable.Range(0, selectedValues.shape[0]), (row) =>
{
for (int col = 0; col < selectedValues.shape[1]; col++)
{
selectedValues.SetData(buf[Storage.Shape.GetIndexInShape(idx[row], col)], row, col);
}
});
return(selectedValues);
}
public static NDArray array(Array array, Type dtype = null, int ndim = 1)
{
dtype = (dtype == null) ? array.GetType().GetElementType() : dtype;
var nd = new NDArray(dtype, new Shape(new int[] { array.Length }));
if ((array.Rank == 1) && (!array.GetType().GetElementType().IsArray))
{
nd.SetData(array);
}
else
{
throw new Exception("Method is not implemeneted for multidimensional arrays or jagged arrays.");
}
return(nd);
}
public static NDArray linspace <T>(double start, double stop, int num, bool entdpoint = true)
{
double steps = (stop - start) / ((entdpoint) ? (double)num - 1.0 : (double)num);
double[] doubleArray = new double[num];
for (int idx = 0; idx < doubleArray.Length; idx++)
{
doubleArray[idx] = start + idx * steps;
}
var nd = new NDArray(typeof(T), doubleArray.Length);
nd.SetData(doubleArray);
return(nd);
}
/// <summary>
/// Draw random samples from a normal (Gaussian) distribution.
/// </summary>
/// <param name="loc">Mean of the distribution</param>
/// <param name="scale">Standard deviation of the distribution</param>
/// <param name="dims"></param>
/// <returns></returns>
public NDArray normal(double loc, double scale, params int[] dims)
{
var array = new NDArray(typeof(double), new Shape(dims));
double[] arr = array.Data <double>();
for (int i = 0; i < array.size; i++)
{
double u1 = 1.0 - randomizer.NextDouble(); //uniform(0,1] random doubles
double u2 = 1.0 - randomizer.NextDouble();
double randStdNormal = Math.Sqrt(-2.0 * Math.Log(u1)) *
Math.Sin(2.0 * Math.PI * u2); //random normal(0,1)
double randNormal = loc + scale * randStdNormal; //random normal(mean,stdDev^2)
arr[i] = randNormal;
}
array.SetData(arr);
return(array);
}
public static NDArray arange(int start, int stop, int step = 1)
{
if (start > stop)
{
throw new Exception("parameters invalid, start is greater than stop.");
}
int length = (int)Math.Ceiling((stop - start + 0.0) / step);
int index = 0;
var nd = new NDArray(np.int32, new Shape(length));
var a = new int[length];
for (int i = start; i < stop; i += step)
{
a[index++] = i;
}
nd.SetData(a);
return(nd);
}
private NDArray setValue4D <T>(NDArray indexes)
{
var buf = Data <T>();
var selectedValues = new NDArray(dtype, new Shape(indexes.size, shape[1], shape[2], shape[3]));
var idx = indexes.Data <int>();
Parallel.ForEach(Enumerable.Range(0, selectedValues.shape[0]), (item) =>
{
for (int row = 0; row < selectedValues.shape[1]; row++)
{
for (int col = 0; col < selectedValues.shape[2]; col++)
{
for (int channel = 0; channel < selectedValues.shape[3]; channel++)
{
selectedValues.SetData(buf[Storage.Shape.GetIndexInShape(idx[item], row, col, channel)], item, row, col, channel);
}
}
}
});
return(selectedValues);
}
