/// <summary>
/// Modify a sequence in-place by shuffling its contents.
/// </summary>
/// <param name="x">The array or list to be shuffled.</param>
/// <remarks>https://docs.scipy.org/doc/numpy/reference/generated/numpy.random.shuffle.html <br></br>Does not copy <paramref name="x"/></remarks>
public void shuffle(NDArray x)
{
var count = x.size;
while (count-- > 1)
{
var swapAt = randomizer.Next(x);
var tmp = x.GetAtIndex(0);
x.SetAtIndex(x.GetAtIndex(swapAt), 0);
x.SetAtIndex(tmp, swapAt);
}
}
public override NDArray Cast(NDArray nd, NPTypeCode dtype, bool copy)
{
if (dtype == NPTypeCode.Empty)
{
throw new ArgumentNullException(nameof(dtype));
}
NDArray clone() => new NDArray(nd.Storage.Clone());
if (nd.Shape.IsEmpty)
{
if (copy)
{
return(new NDArray(dtype));
}
nd.Storage = new UnmanagedStorage(dtype);
return(nd);
}
if (nd.Shape.IsScalar || (nd.Shape.size == 1 && nd.Shape.NDim == 1))
{
var ret = NDArray.Scalar(nd.GetAtIndex(0), dtype);
if (copy)
{
return(ret);
}
nd.Storage = ret.Storage;
return(nd);
}
if (nd.GetTypeCode == dtype)
{
//casting not needed
return(copy ? clone() : nd);
}
else
{
//casting needed
if (copy)
{
if (nd.Shape.IsSliced)
{
nd = clone();
}
return(new NDArray(new UnmanagedStorage(ArraySlice.FromMemoryBlock(nd.Array.CastTo(dtype), false), nd.Shape)));
}
else
{
var storage = nd.Shape.IsSliced ? nd.Storage.Clone() : nd.Storage;
nd.Storage = new UnmanagedStorage(ArraySlice.FromMemoryBlock(storage.InternalArray.CastTo(dtype), false), storage.Shape);
return(nd);
}
}
}
public void UniformMultipleSample()
{
// Generate a uniform random sample from np.arange(5) of size 3:
// This is equivalent to np.random.randint(0,5,3)
int low = 0;
int high = 5;
int nrSamples = 3;
NDArray actual = np.random.choice(high, (Shape)nrSamples);
Assert.AreEqual(actual.size, nrSamples, "Unexpected number of elements");
// Verify that all elements in output are within the range
for (int i = 0; i < actual.size; i++)
{
Assert.IsTrue(actual.GetAtIndex <int>(i) >= low, "Element was less than expected");
Assert.IsTrue(actual.GetAtIndex <int>(i) < high, "Element was greater than expected");
}
}
public void NonUniformSample()
{
// Generate a non-uniform random sample from np.arange(5) of size 3:
int low = 0;
int high = 5;
int nrSamples = 3;
double[] probabilities = new double[] { 0.1, 0, 0.3, 0.6, 0 };
NDArray actual = np.random.choice(5, (Shape)nrSamples, probabilities: probabilities);
Assert.AreEqual(actual.size, nrSamples, "Unexpected number of elements");
// Verify that all elements in output are within the range
for (int i = 0; i < actual.size; i++)
{
Assert.IsTrue(actual.GetAtIndex <int>(i) >= low, "Element was less than expected");
Assert.IsTrue(actual.GetAtIndex <int>(i) < high, "Element was greater than expected");
Assert.IsTrue(actual.GetAtIndex <int>(i) != 1, "Sampled zero-probability element");
Assert.IsTrue(actual.GetAtIndex <int>(i) != 4, "Sampled zero-probability element");
}
}
public override NDArray ReduceProduct(NDArray arr, int? axis_, bool keepdims = false, NPTypeCode? typeCode = null)
{
//in order to iterate an axis:
//consider arange shaped (1,2,3,4) when we want to summarize axis 1 (2nd dimension which its value is 2)
//the size of the array is [1, 2, n, m] all shapes after 2nd multiplied gives size
//the size of what we need to reduce is the size of the shape of the given axis (shape[axis])
var shape = arr.Shape;
if (shape.IsEmpty || shape.size==0)
return NDArray.Scalar(1, (typeCode ?? arr.typecode));
if (shape.IsScalar || (shape.size == 1 && shape.NDim == 1))
{
var r = NDArray.Scalar(typeCode.HasValue ? Converts.ChangeType(arr.GetAtIndex(0), typeCode.Value) : arr.GetAtIndex(0));
if (keepdims)
r.Storage.ExpandDimension(0);
return r;
}
if (axis_ == null)
{
var r = NDArray.Scalar(product_elementwise(arr, typeCode));
if (keepdims)
r.Storage.ExpandDimension(0);
else if (!r.Shape.IsScalar && r.Shape.size == 1 && r.ndim == 1)
r.Storage.Reshape(Shape.Scalar);
return r;
}
var axis = axis_.Value;
while (axis < 0)
axis = arr.ndim + axis; //handle negative axis
if (axis >= arr.ndim)
throw new ArgumentOutOfRangeException(nameof(axis));
if (shape[axis] == 1)
{
//if the given div axis is 1 and can be squeezed out.
if (keepdims)
return new NDArray(arr.Storage.Alias());
return np.squeeze_fast(arr, axis);
}
//handle keepdims
Shape axisedShape = Shape.GetAxis(shape, axis);
var retType = typeCode ?? (arr.GetTypeCode.GetAccumulatingType());
//prepare ret
var ret = new NDArray(retType, axisedShape, false);
var iterAxis = new NDCoordinatesAxisIncrementor(ref shape, axis);
var iterRet = new NDCoordinatesIncrementor(ref axisedShape);
var iterIndex = iterRet.Index;
var slices = iterAxis.Slices;
//resolve the accumulator type
#if _REGEN1
#region Compute
switch (arr.GetTypeCode)
{
%foreach supported_numericals,supported_numericals_lowercase%
case NPTypeCode.#1:
{
switch (retType)
{
%foreach supported_numericals,supported_numericals_lowercase,supported_numericals_onevales%
case NPTypeCode.#101:
{
do
{
var slice = arr[slices];
var iter = slice.AsIterator<#2>();
var moveNext = iter.MoveNext;
var hasNext = iter.HasNext;
|#102 sum = #103;
while (hasNext())
sum *= (#102) moveNext();
ret.Set#101(Converts.To#101(sum), iterIndex);
} while (iterAxis.Next() != null && iterRet.Next() != null);
break;
}
