public static Expression GetReduceExpression(string query, Type itemType)
{
EvoQLBuilder builder = new EvoQLBuilder(query);
ParameterExpression parameterExpression;
EvoQLExpression parse;
var filterexpr = builder.GetFilterExpression(out parse, out parameterExpression);
var get = parse.Tree as GetExpression;
//var interval = get.Interval == null ? null : new IntervalTypes?( TryParseEnum(get.Interval, IntervalTypes.None) );
//var select = TryParseEnum(get.Select, SelectTypes.Count);
var groupBySortDirection = get.GroupByDescending.HasValue ? (get.GroupByDescending == true ? new OrderTypes?(OrderTypes.Descending): new OrderTypes?(OrderTypes.Ascending)) : null;
var groupOverSortDirection = get.GroupOverDescending.HasValue ? (get.GroupOverDescending == true ? new OrderTypes?(OrderTypes.Descending) : new OrderTypes?(OrderTypes.Ascending)) : null;
var dimensions = new ReduceDimension[]
{
new ReduceDimension {
GroupBy = get.GroupBy, OrderBy = new SelectDescriptor {
SourcePath = get.GroupByOrderBy
}, Order = groupBySortDirection, Take = get.GroupByTake, Interval = get.GroupByInterval
},
new ReduceDimension {
GroupBy = get.GroupOver, OrderBy = new SelectDescriptor {
SourcePath = get.GroupOverOrderBy
}, Order = groupOverSortDirection, Take = get.GroupOverTake, Interval = get.GroupOverInterval
}
};
//foreach (var d in dimensions) if (d.GroupBy == GroupByTypes.Date) d.Interval = interval;
var aggregate = get.Select == "Count" ? "Count" : "Sum";
var sourcePath = get.Select == "Count" ? null : get.Select;
var reduceexpr = ReduceExpressionGeneration.GetMapreduceExpression(filterexpr, new SelectDescriptor {
TargetPath = get.Select, SourcePath = sourcePath, Aggregate = aggregate
}, dimensions, itemType);
return(reduceexpr);
}
/// <summary>
/// transforms 2D matrix to 1D row or column vector by taking sum, minimum, maximum or mean value over all the rows
/// </summary>
/// <param name="src">The source 2D matrix</param>
/// <param name="dst">The destination vector.
/// Its size and type is defined by dim and dtype parameters</param>
/// <param name="dim">The dimension index along which the matrix is reduced.
/// 0 means that the matrix is reduced to a single row and 1 means that the matrix is reduced to a single column</param>
/// <param name="rtype"></param>
/// <param name="dtype">When it is negative, the destination vector will have
/// the same type as the source matrix, otherwise, its type will be CV_MAKE_TYPE(CV_MAT_DEPTH(dtype), mtx.channels())</param>
public static void Reduce(InputArray src, OutputArray dst, ReduceDimension dim, ReduceTypes rtype, int dtype)
{
if (src == null)
throw new ArgumentNullException("src");
if (dst == null)
throw new ArgumentNullException("dst");
src.ThrowIfDisposed();
dst.ThrowIfNotReady();
NativeMethods.core_reduce(src.CvPtr, dst.CvPtr, (int)dim, (int)rtype, dtype);
dst.Fix();
GC.KeepAlive(src);
}
/// <summary>
/// transforms 2D matrix to 1D row or column vector by taking sum, minimum, maximum or mean value over all the rows
/// </summary>
/// <param name="dim">The dimension index along which the matrix is reduced.
/// 0 means that the matrix is reduced to a single row and 1 means that the matrix is reduced to a single column</param>
/// <param name="rtype"></param>
/// <param name="dtype">When it is negative, the destination vector will have
/// the same type as the source matrix, otherwise, its type will be CV_MAKE_TYPE(CV_MAT_DEPTH(dtype), mtx.channels())</param>
/// <returns></returns>
public Mat Reduce(ReduceDimension dim, ReduceOperation rtype, int dtype)
{
var dst = new Mat();
Cv2.Reduce(this, dst, dim, rtype, dtype);
return dst;
}
