public static Array <T> Fill <T>(Func <T> f, Array <T> result)
{
return(Array_.ElementwiseOp(result, (n, r, offR, strideR) =>
{
for (int i = 0; i < n; ++i)
{
r[offR] = f();
offR += strideR;
}
}));
}
public static Real Norm2(Array <Real> a)
{
Real result = 0;
Array_.ElementwiseOp(0, a, 0,
(n, x, offsetx, incx) =>
{
result += Blas.dot(n, x, offsetx, incx, x, offsetx, incx);
});
return(result);
}
/// <summary>
/// Fills the result array using the value from a, and the indexes from selected.
/// </summary>
/// <typeparam name="T">The type of a content</typeparam>
/// <param name="thiz"></param>
/// <param name="selected">the result of a ArgMax/ArgMin operation</param>
/// <param name="axis"></param>
/// <param name="axisSize"></param>
/// <param name="keepDims"></param>
/// <param name="result"></param>
/// <returns></returns>
public static Array <T> UnArgmax <T>(this Array <T> thiz, Array <int> selected, int axis, int axisSize, bool keepDims = false, Array <T> result = null)
{
thiz.AssertOfShape(selected);
var dim = thiz.NDim + (keepDims ? 0 : 1);
var shape = new int[dim];
if (keepDims)
{
System.Array.Copy(thiz.Shape, shape, dim);
}
else
{
System.Array.Copy(thiz.Shape, 0, shape, 0, axis);
System.Array.Copy(thiz.Shape, axis, shape, axis + 1, thiz.NDim - axis);
}
shape[axis] = axisSize;
result = result ?? NN.Zeros <T>(shape);
result.AssertOfShape(shape);
var resultInc = result.Stride[axis];
// HACK
// as result have one more shape than thiz and selected, we have to lie about the number of shapes
var resultSlices = new Slice[dim];
for (int i = 0; i < dim; ++i)
{
resultSlices[i] = Slicer._;
}
if (!keepDims)
{
resultSlices[axis] = 0;
}
else
{
resultSlices[axis] = Slicer.Upto(1);
}
var res = result[resultSlices];
Array_.ElementwiseOp(thiz, selected, res,
(n, x, offsetx, incx, s, offsetS, incS, r, offsetR, incR) =>
{
for (int i = 0; i < n; ++i)
{
r[offsetR + resultInc * s[offsetS]] = x[offsetx];
offsetR += incR;
offsetS += incS;
offsetx += incx;
}
});
return(result);
}
public static Array <R> Apply <T1, T2, T3, T4, R>(this Array <T1> a, Array <T2> b, Array <T3> c, Array <T4> d, Func <T1, T2, T3, T4, R> fn, Array <R> result = null)
{
return(Array_.ElementwiseOp(a, b, c, d, result,
(n, x0, offset0, inc0, x1, offset1, inc1, x2, offset2, inc2, x3, offset3, inc3, x4, offset4, inc4) =>
{
if (n < MIN_SIZE_FOR_PARELLELISM)
{
for (int i = 0; i < n; i++)
{
x4[offset4] = fn(x0[offset0], x1[offset1], x2[offset2], x3[offset3]);
offset0 += inc0;
offset1 += inc1;
offset2 += inc2;
offset3 += inc3;
offset4 += inc4;
}
}
else
{
var threads = Blas.NThreads;
Parallel.For(0, threads, t =>
{
var end = (n - 1) / threads + 1;
var off0 = offset0 + t * end * inc0;
var off1 = offset1 + t * end * inc1;
var off2 = offset2 + t * end * inc2;
var off3 = offset3 + t * end * inc3;
var off4 = offset4 + t * end * inc4;
if (t == threads - 1)
{
end = n - t * end;
}
for (int i = 0; i < end; i++)
{
x4[off4] = fn(x0[off0], x1[off1], x2[off2], x3[off3]);
off0 += inc0;
off1 += inc1;
off2 += inc2;
off3 += inc3;
off4 += inc4;
}
});
}
}));
}
/// <summary>
/// Implementations of squared Euclidean distance that doesn't create intermediary array (unlike NN.Norm(a - b)).
/// Faster for small arrays, longer for really big arrays
/// </summary>
/// <param name="a"></param>
/// <param name="b"></param>
/// <returns></returns>
public static Real EuclideanDistance2(Array <Real> a, Array <Real> b)
{
Real result = 0;
Array_.ElementwiseOp(a, b,
(n, x, offx, incx, y, offy, incy) =>
{
for (int _ = 0; _ < n; ++_)
{
var d = x[offx] - y[offy];
result += d * d;
offx += incx;
offy += incy;
}
});
return(result);
}
public static Array <R> Apply <T1, R>(this Array <T1> a, Func <T1, R> fn, Array <R> result = null)
{
if (result == null)
{
result = new Array <R>(a.Shape);
}
Array_.ElementwiseOp(a, result, (n, x0, offset0, inc0, x1, offset1, inc1) =>
{
if (n < MIN_SIZE_FOR_PARELLELISM)
{
for (int i = 0; i < n; i++)
{
x1[offset1] = fn(x0[offset0]);
offset0 += inc0;
offset1 += inc1;
}
}
else
{
var threads = Blas.NThreads;
Parallel.For(0, threads, t =>
{
var end = (n - 1) / threads + 1;
var off0 = offset0 + t * end * inc0;
var off1 = offset1 + t * end * inc0;
if (t == threads - 1)
{
end = n - t * end;
}
for (int i = 0; i < end; i++)
{
x1[off1] = fn(x0[off0]);
off0 += inc0;
off1 += inc1;
}
});
}
});
return(result);
}
public static Array <R> Apply <T1, T2, R>(Array <T1> a, Array <T2> b, Func <T1, T2, R> fn, Array <R> result = null)
{
return(Array_.ElementwiseOp(a, b, result,
(n, x0, offset0, inc0, x1, offset1, inc1, x2, offset2, inc2) =>
{
if (n < MIN_SIZE_FOR_PARELLELISM)
{
for (int i = 0; i < n; i++)
{
x2[offset2] = fn(x0[offset0], x1[offset1]);
offset0 += inc0;
offset1 += inc1;
offset2 += inc2;
}
}
else
{
var threads = Blas.NThreads;
Parallel.For(0, threads, t =>
{
var end = (n - 1) / threads + 1;
var off0 = offset0 + t * end * inc0;
var off1 = offset1 + t * end * inc1;
var off2 = offset2 + t * end * inc2;
if (t == threads - 1)
{
end = n - t * end;
}
for (int i = 0; i < end; i++)
{
x2[off2] = fn(x0[off0], x1[off1]);
off0 += inc0;
off1 += inc1;
off2 += inc2;
}
});
}
}));
}
public static Array <Real> Norm2(Array <Real> a, int axis, Array <Real> result = null)
{
if (axis < 0)
{
axis = a.Shape.Length + axis;
}
if (result == null)
{
result = Zeros <Real>(GetAggregatorResultShape(a, axis, true));
}
else if (result.NDim != a.NDim)
{
result = result.Reshape(GetAggregatorResultShape(a, axis, true));
}
Array_.ElementwiseOp(a, result, (n, x, offx, incx, y, offy, incy) =>
{
y[offy] = Blas.dot(n, x, offx, incx, x, offx, incx);
}, axis);
return(result);
}