Discussion on Black/PEP-8 enforcement

[codykarcher]

Summary

A discussion needs to be had regarding Black/PEP-8 enforcement

Rationale

This EDI example file:

# ===========
# Description
# ===========
# A simple aircraft sizing problem, formulated as a Geometric Program
# From:  Hoburg and Abbeel
#        Geometric Programming for Aircraft Design Optimization
#        AIAA Journal
#        2014

# =================
# Import Statements
# =================
import numpy as np
import pyomo.environ as pyo
from pyomo.environ import units
from pyomo.contrib.edi import Formulation
from pyomo.contrib.edi import BlackBoxFunctionModel

# ===================
# Declare Formulation
# ===================
f = Formulation()

# =================
# Declare Variables
# =================
D   = f.Variable(name = "D",   guess = 300,     units = "N",   description = "total drag force")
A   = f.Variable(name = "A",   guess = 10.0,    units = "-",   description = "aspect ratio")
S   = f.Variable(name = "S",   guess = 10.0,    units = "m^2", description = "total wing area")
V   = f.Variable(name = "V",   guess = 30.0,    units = "m/s", description = "cruising speed")
W   = f.Variable(name = "W",   guess = 10000.0, units = "N",   description = "total aircraft weight")
Re  = f.Variable(name = "Re",  guess = 3e6,     units = "-",   description = "Reynold's number")
C_D = f.Variable(name = "C_D", guess = .025,    units = "-",   description = "Drag coefficient of wing")
C_L = f.Variable(name = "C_L", guess = .5,      units = "-",   description = "Lift coefficent of wing")
C_f = f.Variable(name = "C_f", guess = .003,    units = "-",   description = "skin friction coefficient")
W_w = f.Variable(name = "W_w", guess = 2500,    units = "N",   description = "wing weight")

# =================
# Declare Constants
# =================
k           = f.Constant(name = "k",      value = 1.2,     units = "-",      description = "form factor")
e           = f.Constant(name = "e",      value = 0.96,    units = "-",      description = "Oswald efficiency factor")
mu          = f.Constant(name = "mu",     value = 1.78e-5, units = "kg/m/s", description = "viscosity of air")
rho         = f.Constant(name = "rho",    value = 1.23,    units = "kg/m^3", description = "density of air")
tau         = f.Constant(name = "tau",    value = 0.12,    units = "-",      description = "airfoil thickness to chord ratio")
N_ult       = f.Constant(name = "N_ult",  value = 2.5,     units = "-",      description = "ultimate load factor")
V_min       = f.Constant(name = "V_min",  value = 22,      units = "m/s",    description = "takeoff speed")
C_Lmax      = f.Constant(name = "C_Lmax", value = 2.0,     units = "-",      description = "max CL with flaps down")
S_wetratio  = f.Constant(name = "Srat",   value = 2.05,    units = "-",      description = "wetted area ratio")
W_W_coeff1  = f.Constant(name = "W_c1",   value = 8.71e-5, units = "1/m",    description = "Wing Weight Coefficent 1")
W_W_coeff2  = f.Constant(name = "W_c2",   value = 45.24,   units = "Pa",     description = "Wing Weight Coefficent 2")
CDA0        = f.Constant(name = "CDA0",   value = 0.0306,  units = "m^2",    description = "fuselage drag area")
W_0         = f.Constant(name = "W_0",    value = 4940.0,  units = "N",      description = "aircraft weight excluding wing")

# =====================
# Declare the Objective
# =====================
f.Objective( D )

# ===================================
# Declare some intermediate variables
# ===================================
pi = np.pi
C_D_fuse = CDA0/S
C_D_wpar = k*C_f*S_wetratio
C_D_ind = C_L**2/(pi*A*e)
W_w_strc = W_W_coeff1*(N_ult*A**1.5*(W_0*W*S)**0.5)/tau
W_w_surf = W_W_coeff2 * S

# =======================
# Declare the Constraints
# =======================
f.ConstraintList(
    [
        C_D >= C_D_fuse + C_D_wpar + C_D_ind,
        W_w >= W_w_surf + W_w_strc,
        D >= 0.5*rho*S*C_D*V**2,
        Re == (rho/mu)*V*(S/A)**0.5,
        C_f == 0.074/Re**0.2,
        W == 0.5*rho*S*C_L*V**2,
        W == 0.5*rho*S*C_Lmax*V_min**2,
        W >= W_0 + W_w,
    ]   
)

Becomes this monstrosity

# ===========
# Description
# ===========
# A simple aircraft sizing problem, formulated as a Geometric Program
# From:  Hoburg and Abbeel
#        Geometric Programming for Aircraft Design Optimization
#        AIAA Journal
#        2014

# =================
# Import Statements
# =================
import numpy as np
import pyomo.environ as pyo
from pyomo.environ import units
from pyomo.contrib.edi import Formulation
from pyomo.contrib.edi import BlackBoxFunctionModel

# ===================
# Declare Formulation
# ===================
f = Formulation()

# =================
# Declare Variables
# =================
D = f.Variable(name="D", guess=300, units="N", description="total drag force")
A = f.Variable(name="A", guess=10.0, units="-", description="aspect ratio")
S = f.Variable(name="S", guess=10.0, units="m^2", description="total wing area")
V = f.Variable(name="V", guess=30.0, units="m/s", description="cruising speed")
W = f.Variable(name="W", guess=10000.0, units="N", description="total aircraft weight")
Re = f.Variable(name="Re", guess=3e6, units="-", description="Reynold's number")
C_D = f.Variable(
    name="C_D", guess=0.025, units="-", description="Drag coefficient of wing"
)
C_L = f.Variable(
    name="C_L", guess=0.5, units="-", description="Lift coefficient of wing"
)
C_f = f.Variable(
    name="C_f", guess=0.003, units="-", description="skin friction coefficient"
)
W_w = f.Variable(name="W_w", guess=2500, units="N", description="wing weight")

# =================
# Declare Constants
# =================
k = f.Constant(name="k", value=1.2, units="-", description="form factor")
e = f.Constant(name="e", value=0.96, units="-", description="Oswald efficiency factor")
mu = f.Constant(
    name="mu", value=1.78e-5, units="kg/m/s", description="viscosity of air"
)
rho = f.Constant(name="rho", value=1.23, units="kg/m^3", description="density of air")
tau = f.Constant(
    name="tau", value=0.12, units="-", description="airfoil thickness to chord ratio"
)
N_ult = f.Constant(
    name="N_ult", value=2.5, units="-", description="ultimate load factor"
)
V_min = f.Constant(name="V_min", value=22, units="m/s", description="takeoff speed")
C_Lmax = f.Constant(
    name="C_Lmax", value=2.0, units="-", description="max CL with flaps down"
)
S_wetratio = f.Constant(
    name="Srat", value=2.05, units="-", description="wetted area ratio"
)
W_W_coeff1 = f.Constant(
    name="W_c1", value=8.71e-5, units="1/m", description="Wing Weight Coefficient 1"
)
W_W_coeff2 = f.Constant(
    name="W_c2", value=45.24, units="Pa", description="Wing Weight Coefficient 2"
)
CDA0 = f.Constant(
    name="CDA0", value=0.0306, units="m^2", description="fuselage drag area"
)
W_0 = f.Constant(
    name="W_0", value=4940.0, units="N", description="aircraft weight excluding wing"
)

# =====================
# Declare the Objective
# =====================
f.Objective(D)

# ===================================
# Declare some intermediate variables
# ===================================
pi = np.pi
C_D_fuse = CDA0 / S
C_D_wpar = k * C_f * S_wetratio
C_D_ind = C_L**2 / (pi * A * e)
W_w_strc = W_W_coeff1 * (N_ult * A**1.5 * (W_0 * W * S) ** 0.5) / tau
W_w_surf = W_W_coeff2 * S

# =======================
# Declare the Constraints
# =======================
f.ConstraintList(
    [
        C_D >= C_D_fuse + C_D_wpar + C_D_ind,
        W_w >= W_w_surf + W_w_strc,
        D >= 0.5 * rho * S * C_D * V**2,
        Re == (rho / mu) * V * (S / A) ** 0.5,
        C_f == 0.074 / Re**0.2,
        W == 0.5 * rho * S * C_L * V**2,
        W == 0.5 * rho * S * C_Lmax * V_min**2,
        W >= W_0 + W_w,
    ]
)

And so in the documentation, I have no way to show potential users the prettiness and awesomeness that is the first file, because PEP-8 is ... annoying.

Description

Above

Additional information

I am seeking either 1) a way to exempt my ~5 large example files from PEP-8 enforcement during testing or 2) to be told my pretty code is not worth compromising a core pyomo design decision

[mrmundt]

#329 - Linking to the original PEP issue.

[jsiirola]

FWIW, I would be OK entertaining a process by which specific examples could be exempted from Black.