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| 1 | +// |
| 2 | +// g++ -std=c++20 -g -Wall -o ranges $(python-config --includes) ranges.cpp $(python-config --ldflags --embed) |
| 3 | +// |
| 4 | +// g++ -std=c++17 -g -Wall -o ranges $(python-config --includes) ranges.cpp $(python-config --ldflags --embed) |
| 5 | +// |
| 6 | +#include "../matplotlibcpp.h" |
| 7 | + |
| 8 | +#include <iostream> |
| 9 | +#include <list> |
| 10 | +#include <map> |
| 11 | +#include <span> |
| 12 | +#include <string> |
| 13 | +#include <vector> |
| 14 | + |
| 15 | +#define UNUSED(x) (void)(x) |
| 16 | + |
| 17 | +using namespace std; |
| 18 | +namespace plt = matplotlibcpp; |
| 19 | + |
| 20 | +int main() |
| 21 | +{ |
| 22 | + plt::detail::_interpreter::get(); |
| 23 | + |
| 24 | + |
| 25 | +#if __cplusplus >= CPP20 |
| 26 | + |
| 27 | + // C-style arrays with multiple rows. |
| 28 | + |
| 29 | + // Care with column-major vs row-major! |
| 30 | + // C and Python are row-major, but usually a time series is column-major |
| 31 | + // and we want to plot the columns. |
| 32 | + // In the example below, these columns are [3,1,4,5] and [5,4,1,3], so |
| 33 | + // the data must be stored like this: |
| 34 | + time_t t[]={1, 2, 3, 4}; |
| 35 | + double data [] = { |
| 36 | + 3, 5, |
| 37 | + 1, 4, |
| 38 | + 4, 1, |
| 39 | + 5, 3 |
| 40 | + }; |
| 41 | + |
| 42 | + // Use std::span() to convert to a contiguous range (O(1)). |
| 43 | + // Data won't be copied, but passed as a pointer to Python. |
| 44 | + plt::plot(span(t, 4), span(data, 8)); |
| 45 | + plt::grid(true); |
| 46 | + plt::title("C-arrays, with multiple columns"); |
| 47 | + plt::show(); |
| 48 | + |
| 49 | +#else |
| 50 | + |
| 51 | + cerr << __FILE__ << ": " << __FUNCTION__ << ": " << __LINE__ << ": " |
| 52 | + << "No support for contiguous ranges." << endl; |
| 53 | + |
| 54 | +#endif |
| 55 | + |
| 56 | + // vectors |
| 57 | + |
| 58 | + // Vectors are also contiguous ranges. |
| 59 | + // In C++20, as with span, plot resolves to plot(contiguous_range). |
| 60 | + // In C++ < 20 plot resolves to plot(vector). |
| 61 | + vector<double> x={1, 2, 3, 4, 5}; |
| 62 | + vector<double> y={0, 1, 0, -1, 0}; |
| 63 | + plt::plot(x, y); |
| 64 | + plt::grid(true); |
| 65 | + plt::title("vectors"); |
| 66 | + plt::show(); |
| 67 | + |
| 68 | + |
| 69 | + // lists |
| 70 | + |
| 71 | + // By contrast, lists are non-contiguous (but iterable) containers, so |
| 72 | + // plot resolves to plot(iterable). |
| 73 | + list<double> u { 1, 2, 3, 4, 5}; |
| 74 | + list<double> v { 0, -1, 0, 1, 0}; |
| 75 | + plt::plot(u, v, ""); |
| 76 | + plt::grid(true); |
| 77 | + plt::title("Lists (non-contiguous ranges)"); |
| 78 | + plt::show(); |
| 79 | + |
| 80 | + |
| 81 | + // All together now |
| 82 | +#if __cplusplus >= CPP20 |
| 83 | + |
| 84 | + // If span is not last, plot resolves to plot(iterable), which copies data. |
| 85 | + // That's because in the dispatch plot() we have plot_impl() && plot() |
| 86 | + // (i.e. plot_impl() comes first), and we only have iterable and |
| 87 | + // callable plot_impl(). That sends us to the iterable plot_impl(), |
| 88 | + // rather than to plot(contiguous_range). |
| 89 | + // |
| 90 | + // TODO: have 3 tags plot_impl(): iterable, callable and contiguous range. |
| 91 | + plt::plot(span(t, 4), span(data, 8), "", x, y, "b", u, v, "r"); |
| 92 | + |
| 93 | + // This resolves to plot(contiguous_range) and does not copy data. |
| 94 | + // plt::plot(x, y, "b", u, v, "r", span(t, 4), span(data, 8)); |
| 95 | +#else |
| 96 | + plt::plot(x, y, "b", u, v, "r"); |
| 97 | +#endif |
| 98 | + plt::grid(true); |
| 99 | + plt::title("Variadic templates recursion"); |
| 100 | + plt::show(); |
| 101 | + |
| 102 | + plt::detail::_interpreter::kill(); |
| 103 | + |
| 104 | + return 0; |
| 105 | +} |
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