ode | Go binding for the Open Dynamics Engine library

This is my first attempt on a complex coupled ode equation:

I have an ODE which I would like to solve using compiled C code called from R's deSolve package. The ODE in question is I an exponential decay model (y'=-d* exp(g* time)*y): But running the compiled code from within R gives different results to R's native deSolve. It's as is there they are flipped 180º. What's going on?

I am trying to solve a system with seven differential equations. And I am having a hard time grapsing the ode45 solver.
These are the equations:

ω2_dot = -0.75 ω1 ω3

ω1_dot = 0.75 ω2 ω3 + 0.2

ω3_dot = 0

q1_dot = 1/2(ω1q4 + ω2q3 - ω3q2)

q2_dot = 1/2(ω2q4 + ω3q1 - ω1q3)

q3_dot = 1/2(ω3q4 + ω1q2 - ω2q2)

q4_dot = -1/2(ω1q1 + ω2q2 + ω3q3)

The initial values are listed in the inital_val in the same order. Here is what I have so far:

I am trying to solve this system of ODEs through deSolve, dX/dt = -X*a + (Y-X)b + c and dY/dt = -Ya + (X-Y)*b for time [0,200], a=0.30, b=0.2 but c is 1 for time [50,70] and 0 otherwise. The code I have been using is,

I am doing a project to which I predict the behaviour of COVID using a SEIRDV model. I have created the differential equations and have set initial parameters. I am solving these ODE's using the forward Euler method. When I create a program to find the S, E, I, R, D, V at each day for 180 days and display it using matplotlib. I get an error which can be seen below. I believe this is due to the following operation.

I am seeking to find optimal control (aoa and bank angle) to maximize cross range for a shuttle type reentry vehicle using Gekko. Below is my code currently and I am getting a "Solution not found" with "EXIT: Maximum Number of Iterations Exceeded". The simulation assumes a point mass with a non-rotating earth frame. The EOMS are 6 coupled, non-linear ODEs. I have tried using different solvers, implementing/removing state and control constraints, increasing maximum number of iterations, etc. I am not confident with my setup and implementation of the problem in Gekko and am hoping for some feedback on what I can try next. I have tried to follow the setup and layouts in APMonitor's Example 11. Optimal Control with Integral Objective, Inverted Pendulum Optimal Control, and Example 13. Optimal Control: Minimize Final Time. Solutions I'm seeking are below.

Any help is very much appreciated!

I'm not really versatile in regex, especially multi-line so i hope someone can help me out here.

Based on the following example, I'm trying to find all the field definitions of type Code that don't have the "TableRelation"-property set.

so in this example, this would be the field "Holding Name"

I am trying to solve the System of coupled differential equation but I got following error can any one resolve this problem

dY[1] = (1/M*C_p)((m_c*C_p*(Y[0]-Y[1]))-(U_l*(A_s_2)*(Y[1]-Ta))) TypeError: 'float' object is not callable

I am trying to solve a BVP problem (Cosserat rod ODE) with gekko. The goal is to find the initial conditions nsol and msol (which correspond to the internal forces and moments of the rod) that minimize the cost function (the position of the final point of the rod), when integrating, the cosserat equations gives us P, R, nsol, msol, which correspond to the position, orientation, internal forces and moment in a section of the rod.

but I keep getting this error:

Exception: @error: Equation Definition Equation without an equality (=) or inequality (>,<) false STOPPING...

I am a beginner with gekko and although I have seen multiple threads with the same error, the source of the error seems to be different everytime. Could anyone please point me in the right direction ? Thank you very much