How to use quiver w/o meshgrid?

[acxz]

Hello!

I am trying to use quiver(x, y, u, v) for 1D data series.
Here is a minimal working example that I am trying to create:

#include <cmath>
#include <matplot/matplot.h>

int main() {
    using namespace matplot;

    // Produces 10 entries
    auto x = iota(0, 2.0 / 20, 2);
    auto y = iota(0, 2.0 / 20, 2);

    // Produces 11 entries
    // auto theta = iota(0, 2 * M_PI / 20, 2 * M_PI);

    // Produces 10 entries
    std::vector<double> theta;
    for (int t = 0; t < x.size(); t++) {
        theta.push_back(0 + 2 * M_PI / x.size() * t);
    }

    auto u =
        transform(theta, [](double theta) { return 1; });
    auto v =
        transform(theta, [](double theta) { return 0.001; });

    quiver(x, y, u, v);
    show();
    return 0;
}

I expect a plot that has the tail points of the quiver at the (x, y) locations and the head point of the quiver at (x + u, y + v). So for this example it would be something like a series of quivers originating on the y = x line with the heads of the quiver all pointing roughly in the +x direction with a magnitude of 1.

This is the plot that is actually generated.

Notice that for the most part the plot is correct. But the u and v vectors don't make sense according to 1 and 0.001.

Thank you!

[acxz]

Looks like I ended up discovering a bug where the user input direction is not respected due to some incorrect scaling logic. See: #279