OpenGL Expression: Vector subscript out of range

Question

I am in the process of writing a script to draw a circle and draw lines around that circle, call it a low resolution depiction of the Corona Virus. I am using vectors to store the coordinates of the points. For reasons not yet known, I receive a vector subscript out of range debug error. Since it is in run time and not compile time, I do not get the line number for the same error. 24 hours back, I got the same error while using vectors for another problem.

• Visual Studio 2019
• OpenGL

Below is the snippet of the Corona Virus program.

vector<double> multiply(vector<vector<double>> mat1, vector<double> mat2) {
    vector<double> product;
    for (int i = 0; i < mat1.size(); i++)
        for (int j = 0; j < mat2.size(); j++)
            product[i] += mat1[i][j] * mat2[j];
    return product;
}

vector<double> rotate(vector<double> P, double theta) {
    vector<vector<double>> R(3, vector<double>(3, 0));
    vector<double> product;
    R[0][0] = cos(theta);
    R[0][1] = -sin(theta);
    R[1][0] = sin(theta);
    R[1][1] = cos(theta);
    product = multiply(R, P);
    return product;
}

void coronaDemo() {
    glClear(GL_COLOR_BUFFER_BIT);
    double theta = 90;
    glColor3f(1, 0, 0);
    drawCircle();
    vector<vector<double>> points = {
        {0, 100, 1},
        {0, 300, 1}
    };
    for (size_t i = 0; i < points.size(); i++)
    {
        for (size_t j = 0; j < points[i].size() - 1; j++)
        {
            cout << points[i][j] << " ";
        }
        cout << "\n";
    }
    glBegin(GL_LINES);
    for (size_t i = 0; i < points.size(); i++)
    {
        vector<double> temp;
        temp = rotate(points[i], theta);
        glVertex2d(temp[0], temp[1]);
        temp.clear();
    }
    glEnd();
    glFlush();
}

int main(int argc, char** argv) {
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
    glutInitWindowSize(HEIGHT, HEIGHT);
    glutCreateWindow("Corona Virus");
    myInit();
    glutDisplayFunc(coronaDemo);
    glutMainLoop();
    return 1;
}

Kindly help me identify the reason for the said error. Do ask any other information that might be required to frame the question better.