In gp(F0, g0, A = A, b = b) : No restrictions provided, trying solve()
This likely means that while you've specified A and b, the solver doesn't
recognize any inequality (<=) or equality (=) restrictions - because in the
context of the gp() function from the CVXR or similar geometric programming
libraries in R, you're expected to provide explicit inequality/equality
markers or properly formatted constraint matrices.
So what's missing? Probably an argument like ineq = ... or eq = ... to
declare the type of constraint.
Here's how to express your constraint properly, assuming the library expects
inequalities or equalities to be marked explicitly:
# Properly declare equality constraints
gp(F0, g0, eq=A, eq.b=b)
Or possibly (depending on the package):
gp(F0, g0, Aeq=A, beq=b)
If the solver expects inequality constraints:
gp(F0, g0, A=A, b=b, meq=1) # Indicating 1 equality constraint
Jeff Reichman
-----Original Message-----
From: R-help <r-help-boun...@r-project.org> On Behalf Of
kol...@science.iwi.ac.at
Sent: Wednesday, July 30, 2025 2:32 PM
To: r-help@r-project.org
Subject: [R] Problem with function gp in package cccp
Dear all!
I tried to solve a simple test example of a geometric program:
minimize x + y s.t. xy = 1
The solution should be (1, 1).
I tried:
F0 <- diag(2) # [m * n] m = number of terms of the
posynomial, n = number of variables
g0 <- log(matrix(1,2,1)) # [m * 1]
A <- matrix(c(1,1), 1, 2) # one constraint, one row
b <- log(matrix(1,1,1))
RES <- gp(F0, g0, A=A, b=b)
Though I received the correct solution, the function gives a warning:
In gp(F0, g0, A = A, b = b) : No restrictions provided, trying solve().
Also, when I try
RES <- gp(F0, g0, A="A", b=b)
or
gp(F0, g0)
receiving the same result, I find out, that my equality constraints are not
considered at all.
In my view, the unconstraint problem should have (0, 0) as a solution, btw.
Am I missing something fundamental?
Thanks in advance!
Wolfgang
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