histogram2d
Syntax
histogram2d(X, Y, [bins=10], [range], [density], [weights]
Arguments
X and Y are numeric vectors of the same length, indicating the x and y coordinates of the points to be histogrammed. NULL values are not allowed.
bins (optional) is a numeric scalar, vector or a tuple. The default value is 10. NULL values are not allowed. It can be:
- Scalar: The number of bins for two dimensions.
- Vector: The bin edges for the two diemensions. The vector must be strictly increasing.
- Tuple with two scalars: The number of bins for each dimension.
- Tuple with two vectors: The bin edges for each dimension.
- Tuple with a scalar and a vector: The scalar represents the number of bins and the vector represents the bin edges, for the corresponding dimension.
range (optional) is a tuple with two 2-length vectors, indicating the bin edges along each dimension (if not specified explicitly in the bins parameters). All values outside of this range will be considered outliers and not tallied in the histogram. The default value is NULL.
density (optional) is a Boolean scalar. If false (default), returns the number
of samples in each bin. If true, returns the probability density function at
the bin, i.e., bin_count / sample_count / bin_area.
weights (optional) is a numeric vector of the same length as X/Y for weighing each sample (x_i, y_i). The default value is NULL. Note that NULL values are not allowed in the vector. weights are normalized to 1 if density is true. Otherwise, the values of the returned histogram are equal to the sum of the weights belonging to the samples falling into each bin.
Details
Compute the bi-dimensional histogram of two data samples.
Return values: A dictionary with the following keys:
- H: The bi-dimensional histogram of samples x and y. Values in x are histogrammed along the first dimension and values in y are histogrammed along the second dimension. It is a matrix in the shape of (nx, ny), where nx and ny are the number of bins at each dimension.
- xedges: A vector of length (nx+1) indicating the bin edges along the first dimension.
- yedges: A vector of length (ny+1) indicating the bin edges along the second dimension.
Examples
Example 1. Set bin edges and density=false.
x = [0.1, 0.2, 0.5, 0.7, 0.9]
y = [0.2, 0.4, 0.6, 0.8, 1.0]
bins = [[0, 0.3, 0.6, 1.0], [0, 0.5, 1.0]]
density = false
result = histogram2d(x, y, bins, ,density)
/* Output:
H->#0 #1
-- --
2 0
0 1
0 2
xedges->[0,0.3,0.6,1]
yedges->[0,0.5,1]
*/Example 2. Set bin number, edges, weights and density=false.
x = [0.2, 0.4, 0.6, 0.8, 1.0]
y = [0.3, 0.5, 0.7, 0.9, 1.1]
bins = [2, [0.3, 0.5, 1.1]]
weights = [1, 2, 3, 4, 5]
density = true
result = histogram2d(x, y, bins, ,density, weights)
/* Output:
H->#0 #1
-- --
1 5
0 9
xedges->[0.2,0.6,1]
yedges->[0.3,0.5,1.1]
*/