Using acados on google colab

User Questions
1

any of you already used acados in google colab?

I managed to install acados inside colab and run the getting started .py files using the commands below (adapted from the installation instructions)

however I’m having troubles importing the commands inside cells of the notebook so I can code inside the notebook. Any hints on that to make it work on google colab notebooks?

!git clone https://github.com/acados/acados.git
%cd acados
!git submodule update --recursive --init


!mkdir -p build
%cd build
!cmake -DACADOS_WITH_QPOASES=ON ..
!make install -j4

!pip install -e /content/acados/interfaces/acados_template

import os
os.environ['LD_LIBRARY_PATH']='/usr/local/nvidia/lib:/usr/local/nvidia/lib64:/content/acados/lib'
os.environ['ACADOS_SOURCE_DIR']='/content/acados'
!env

%cd /content/acados/examples/acados_python/getting_started/
!echo "y" | python3 minimal_example_ocp.py

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2

Hi,

I was following the steps in the GitHub workflow and managed to run the example by installing the Tera renderer after setting up the environment variables:

%cd /content/acados
!./.github/linux/install_tera.sh
Complete code 
# acados setup
!git clone https://github.com/acados/acados.git
%cd acados
!git submodule update --recursive --init

!mkdir -p build
%cd build
!cmake ..
!make install -j4

!pip install -e /content/acados/interfaces/acados_template

import os
os.environ['LD_LIBRARY_PATH']='/usr/local/nvidia/lib:/usr/local/nvidia/lib64:/content/acados/lib'
os.environ['ACADOS_SOURCE_DIR']='/content/acados'

%cd /content/acados
!./.github/linux/install_tera.sh

# test run
%cd /content/acados/examples/acados_python/getting_started/
!echo "y" | python3 minimal_example_ocp.py

Hope this helps,
Josip

1 Like
3

Hi Josip,

the code I sent actually runs the .py file successfully and installs tera (see the line with echo “y”)

so we’re all in the same page

the problem occurs when I run code inside the cells, as it cannot find acados_template module

did you manage to run cells in colab calling acado code? please see the print I sent

4

Oh, I see, sorry for the misunderstanding…
No, I get the same error when I run code in a separate cell :confused:

Hopefully someone with more experience can help.

Kind regards,
Josip

1 Like
5

Hi Helon,

Maybe colab sets up a new python enviroment that does not know where acados_template is.
Can you double check that the correct python environment is running?

Cheers,
Andrea

6

Indeed Andrea, the envs are different, thanks for pointing this out.

I managed to run the example on colab cells, but needed to use ctypes to load all .so files needed when calling AcadosOcpSolver()

maybe reflecting the same env in shell / colab notebook cells will lead to a more elegant solution and easier to run acados on colab. I’ll try to work on this

below is the code to run on colab as mentioned (simply pasting in a cell and run will reproduce):


!git clone https://github.com/acados/acados.git
%cd acados
!git submodule update --recursive --init

%mkdir -p build
%cd /content/acados/build
!cmake -DACADOS_WITH_QPOASES=ON ..
!make install -j4

%pip install -e /content/acados/interfaces/acados_template

# below is needed for running the minimal_example_ocp.py, so that tera is installed 
import os
os.environ['LD_LIBRARY_PATH']='/usr/local/nvidia/lib:/usr/local/nvidia/lib64:/content/acados/lib'
os.environ['ACADOS_SOURCE_DIR']='/content/acados'

%cd /content/acados/examples/acados_python/getting_started/
!echo "y" | /usr/bin/python3 minimal_example_ocp.py

import sys
sys.path.append("/content/acados/interfaces/acados_template") # necessary so colab knows where to find acados_template
from acados_template import AcadosOcp, AcadosOcpSolver
from pendulum_model import export_pendulum_ode_model
import numpy as np
import casadi as ca
from utils import plot_pendulum

import ctypes # necessary so colab knows where to find *.so files
ctypes.cdll.LoadLibrary('/content/acados/lib/libqpOASES_e.so')
ctypes.cdll.LoadLibrary('/content/acados/lib/libblasfeo.so')
ctypes.cdll.LoadLibrary('/content/acados/lib/libhpipm.so')

#### example code begins

# create ocp object to formulate the OCP
ocp = AcadosOcp()

# set model
model = export_pendulum_ode_model()
ocp.model = model

Tf = 1.0
nx = model.x.rows()
nu = model.u.rows()
N = 20

# set prediction horizon
ocp.solver_options.N_horizon = N
ocp.solver_options.tf = Tf

# cost matrices
Q_mat = 2*np.diag([1e3, 1e3, 1e-2, 1e-2])
R_mat = 2*np.diag([1e-2])

# path cost
ocp.cost.cost_type = 'NONLINEAR_LS'
ocp.model.cost_y_expr = ca.vertcat(model.x, model.u)
ocp.cost.yref = np.zeros((nx+nu,))
ocp.cost.W = ca.diagcat(Q_mat, R_mat).full()

# terminal cost
ocp.cost.cost_type_e = 'NONLINEAR_LS'
ocp.cost.yref_e = np.zeros((nx,))
ocp.model.cost_y_expr_e = model.x
ocp.cost.W_e = Q_mat

# set constraints
Fmax = 80
ocp.constraints.lbu = np.array([-Fmax])
ocp.constraints.ubu = np.array([+Fmax])
ocp.constraints.idxbu = np.array([0])

ocp.constraints.x0 = np.array([0.0, np.pi, 0.0, 0.0])

# set options
ocp.solver_options.qp_solver = 'PARTIAL_CONDENSING_HPIPM' # FULL_CONDENSING_QPOASES
# PARTIAL_CONDENSING_HPIPM, FULL_CONDENSING_QPOASES, FULL_CONDENSING_HPIPM,
# PARTIAL_CONDENSING_QPDUNES, PARTIAL_CONDENSING_OSQP, FULL_CONDENSING_DAQP
ocp.solver_options.hessian_approx = 'GAUSS_NEWTON' # 'GAUSS_NEWTON', 'EXACT'
ocp.solver_options.integrator_type = 'IRK'
# ocp.solver_options.print_level = 1
ocp.solver_options.nlp_solver_type = 'SQP' # SQP_RTI, SQP
ocp.solver_options.globalization = 'MERIT_BACKTRACKING' # turns on globalization

ocp_solver = AcadosOcpSolver(ocp)

simX = np.zeros((N+1, nx))
simU = np.zeros((N, nu))

status = ocp_solver.solve()
ocp_solver.print_statistics() # encapsulates: stat = ocp_solver.get_stats("statistics")

if status != 0:
    raise Exception(f'acados returned status {status}.')

# get solution
for i in range(N):
    simX[i,:] = ocp_solver.get(i, "x")
    simU[i,:] = ocp_solver.get(i, "u")
simX[N,:] = ocp_solver.get(N, "x")

plot_pendulum(np.linspace(0, Tf, N+1), Fmax, simU, simX, latexify=True, time_label=model.t_label, x_labels=model.x_labels, u_labels=model.u_labels)