Skip to content

Element Access

Method
MapContainer
Access and throw exception if it doesn't exist
mapped_type &at(const key_type &k);
const mapped_type &at(const key_type &k) const;
Access and create new element if it doesn't exist
mapped_type &operator[](https://github.com/alandefreitas/pareto/blob/master/);
mapped_type &operator[](https://github.com/alandefreitas/pareto/blob/master/);
template <typename... Targs> mapped_type &operator()(const dimension_type &x1, const Targs &...xs);

Parameters

  • k - the key of the element to find
  • x1 - the value of the element to find in the first dimension
  • xs - the value of the element to find in other dimensions

Return value

A reference to the element associated with that key.

Exceptions

std::out_of_range if the container does not have an element with the specified key

Complexity

\[ O(m \log n) \]

Notes

Unlike in a pareto::spatial_map, the insert operation for archives is allowed to fail when the new element is already dominated by all fronts and exceeds the maximum capacity of the archive. In this case, the operator[] will return a reference to a placeholder that is not ultimately inserted in the front.

Info

See the section on spatial containers / element access for more information.

Example

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
archive<double, 3, unsigned> ar({min, max, min});
// Set some values
ar(-2.57664, -1.52034, 0.600798) = 17;
ar(-2.14255, -0.518684, -2.92346) = 32;
ar(-1.63295, 0.912108, -2.12953) = 36;
ar(-0.653036, 0.927688, -0.813932) = 13;
ar(-0.508188, 0.871096, -2.25287) = 32;
ar(-2.55905, -0.271349, 0.898137) = 6;
ar(-2.31613, -0.219302, 0) = 8;
ar(-0.639149, 1.89515, 0.858653) = 10;
ar(-0.401531, 2.30172, 0.58125) = 39;
ar(0.0728106, 1.91877, 0.399664) = 25;
ar(-1.09756, 1.33135, 0.569513) = 20;
ar(-0.894115, 1.01387, 0.462008) = 11;
ar(-1.45049, 1.35763, 0.606019) = 17;
ar(0.152711, 1.99514, -0.112665) = 13;
ar(-2.3912, 0.395611, 2.78224) = 11;
ar(-0.00292544, 1.29632, -0.578346) = 20;
ar(0.157424, 2.30954, -1.23614) = 6;
ar(0.453686, 1.02632, -2.24833) = 30;
ar(0.693712, 1.12267, -1.37375) = 12;
ar(1.49101, 3.24052, 0.724771) = 24;

// Access value
if (ar.contains({1.49101, 3.24052, 0.724771})) {
    std::cout << "Element access: " << ar(1.49101, 3.24052, 0.724771) << std::endl;
} else {
    std::cout << "{1.49101, 3.24052, 0.724771} was dominated" << std::endl;
}

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
ar = pareto.archive()
# Set some values
ar[-2.57664, -1.52034, 0.600798] = 17
ar[-2.14255, -0.518684, -2.92346] = 32
ar[-1.63295, 0.912108, -2.12953] = 36
ar[-0.653036, 0.927688, -0.813932] = 13
ar[-0.508188, 0.871096, -2.25287] = 32
ar[-2.55905, -0.271349, 0.898137] = 6
ar[-2.31613, -0.219302, 0] = 8
ar[-0.639149, 1.89515, 0.858653] = 10
ar[-0.401531, 2.30172, 0.58125] = 39
ar[0.0728106, 1.91877, 0.399664] = 25
ar[-1.09756, 1.33135, 0.569513] = 20
ar[-0.894115, 1.01387, 0.462008] = 11
ar[-1.45049, 1.35763, 0.606019] = 17
ar[0.152711, 1.99514, -0.112665] = 13
ar[-2.3912, 0.395611, 2.78224] = 11
ar[-0.00292544, 1.29632, -0.578346] = 20
ar[0.157424, 2.30954, -1.23614] = 6
ar[0.453686, 1.02632, -2.24833] = 30
ar[0.693712, 1.12267, -1.37375] = 12
ar[1.49101, 3.24052, 0.724771] = 24

# Access value
if [1.49101, 3.24052, 0.724771] in ar:
    print('Element access:', ar[1.49101, 3.24052, 0.724771])
else:
    print("[1.49101, 3.24052, 0.724771] was dominated")

1
Element access: 24