Questions tagged [constraint]
The constraint tag has no usage guidance.
108
questions
2
votes
0answers
50 views
How to generate a large number of constraints for all indices ($\forall i$)
Is it possible to generate a set of constraints in the form "$\forall$".
For example:
\begin{align}
\min\ & f\left(\sum x_i\right)\\
s.t.\ & \\
& x_i\geq 17 && \forall i=...
1
vote
1answer
106 views
Solving symbolic system of non-linear equations takes too long
I am trying to solve a set of system of symbolic non-linear equations:
...
4
votes
1answer
50 views
Nonlinearmodelfit with integral or nintegral as constrain
Until now I have been using the Nonlinearmodelfit without any issues, but I want to add a new constrain (Integral or NIntegral) to my modelfit.
My fitting function is ...
0
votes
0answers
38 views
Help with NMinimize and setting limits
Im trying to minimize the error of a function Penality that i have defined and am using the following code.
...
0
votes
1answer
78 views
Global optimisation - Error bound on NMaximize?
Is it possible to obtain an error bound on NMaximize? e.g. convert the number returned by NMaximize into a rigorous upper bound ...
1
vote
0answers
31 views
Tackling variational problem with constraints [closed]
I need to minimize (preferably symbolically) functional with constraints:
$$
F = \int_{0}^{\pi/2} f(x)cos{x}dx\,\\
1.1 \geq f(x) \geq 0\\
2.\int_{0}^{\pi/2} f(x)dx=Const\\
3. f(0) =1\\
4.f(\pi/2) = 0\...
0
votes
1answer
49 views
1
vote
1answer
79 views
Constrained NDSolve
Consider n particles constrained on the surface of a unit sphere. $i^{th}$ particle experiences a force from every other $j^{th}$ of the form $$\vec{f_{ij}}=\frac{k ...
4
votes
1answer
91 views
How do I tell FindMinimum to only work with positive, real numbers?
I have a function that I'm trying to minimize. It currently works reasonably well with this:
...
0
votes
0answers
32 views
Maximising the minimum of a linear combination of polynomials
I have list of finArray of 6 rational polynomials, of degrees of about 4 to 6, in around 200 variables allVars, along with a ...
0
votes
2answers
46 views
Is it possible to use Reduce in a way that “eliminates” some unwanted variables, and only gives constraints between wanted variables?
Reduce[{x == z, y == z}] gives y == z && x == z but say I'm only interested in constraints that appear between ...
0
votes
1answer
34 views
Find parameter value for which sharply-peaked constrained 3d-integral equals 1
I want to find the value (desirably to high-precision) of the parameter $i$ for which
the constrained 3d integration
...
0
votes
0answers
35 views
What happens when NMinimize constraints are unsolvable
I have an algebraic function in many variables which outputs a vector $v$.
The coefficients of the vector are high degree polynomials in many variables.
I want to maximize $\;v[[1]] /Norm[v]\;$ ...
1
vote
1answer
70 views
Finding whether the convex cone from a vector list is null
Given a list of vectors, I want to find whether there exists a vector such that its dot product with those in the list is all (semi)positive, or at least above a certain small negative value.
5
votes
3answers
123 views
How to randomly generate a positive semidefinite matrix?
How would I randomly generate a positive semidefinite matrix? I'm aware how to generate a random $n\times n$ matrix with real values between -1 and 1 with
...
1
vote
1answer
43 views
Show, if possible, small isolated “islands” in the unit cube using RegionPlot3D
I have a certain three-dimensional constraint
...
1
vote
1answer
66 views
ArgMin over intervals and discrete sets
I was playing with ArgMin but I'm not sure how to use it for constrained optimization.
For example,
ArgMin[x^2, x]
returns <...
1
vote
2answers
45 views
Find maximum of x given a bunch of constraints [closed]
Trying to find maximum of x given that '''0<=x<=3''' and some other stuff. This works fine:
Clear[x, y]
FindMaximum[{x, 0<=x<=3}, x]
But this does ...
3
votes
3answers
125 views
Constraint of NDSolve with an integral of the solution
I'd like to use NDSolve and to make a constraint with an integral.
For example, take the very simple : $$f'(x)=-f(x)/x_0 $$
the solution is $$f(x)=f_0 e^{-x/x_0} $$
And $f_0$ is given by : $$\int_0^{+\...
1
vote
2answers
105 views
Optimize with constraints
I want to find the smallest $k$ such that $kx^2 \ge (\sin(x)-x)^2$ for all scalar $x\in[a,\ b]$? Obviously, I can do it analytically, but how can I do it (symbolically) in Mathematica? I am new to ...
0
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0answers
34 views
0
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0answers
25 views
Establish a certain formula for a constrained integration over an ordered subsection of a 3-simplex
Some ten years ago, I convinced myself that the solution to this problem
(although, it would seem, not carried out with this specific command then)
...
0
votes
1answer
57 views
0
votes
1answer
64 views
NonlinearModelFit failing because varible range [closed]
I'm trying to fit a specific equation to a plot of points but its failing because the equation has a square root in it and I need to keep the values of x between a certain range. I know how to do this ...
4
votes
3answers
460 views
How to set a tolerance level for equality constraints
Given two equality constraints: x+y==250 and z+p==65 where x=190, y=50, z=45, p=15, I want ...
1
vote
1answer
37 views
Maximize violate constraint of non approximated function
here is my code
Maximize[{-(10/17) - x + (20 (1 + x))/(17 (2 + x)), 0 <= x <= 1.5}, x]
The result I got:
{6.66134*10^-16, {x -> -9.79755*10^-16}}
As you ...
5
votes
3answers
251 views
12
votes
0answers
170 views
Linear programming with lazy constraints
Does Mathematica offer any means for solving linear programming problems with "lazy constraints", as described e.g. here?
While I am not very familiar with linear programming, my understanding of the ...
3
votes
1answer
125 views
Solving a stiff nonlinear ODE system
The system I am trying to solve is simple, but looks pretty stiff and I have unsuccessfully tried to solve it with StiffnessSwitching. It is the following one:
<...
1
vote
1answer
26 views
Numerical Maximization with Alternating Sum
I need to maximize a function that involves an alternating sum and a set of constraints. I have tried the following code:
NMaximize[{(-1)^{m}*n!, n + m == 7, m > 0, n > 0}, {m, n}]
However, the ...
6
votes
4answers
859 views
RandomInteger with equal number of 1 and -1
I want to generate a list of random integers with only three values 1,0,-1. I know it can be done through RandomInteger[{-1, 1}, n]. How can I impose constraint on this list so that every integers in ...
0
votes
1answer
58 views
0
votes
0answers
77 views
Differential equation with some condition
I'm trying to solve a harmonic oscillator equation with a time-dependent (real) frequency,
$v_k''(\tau) + \omega_k^2(\tau) v_k(\tau)=0$,
where
$\omega_k^2(\tau) = k^2 - \frac{2}{\tau^2}$.
This ...
0
votes
0answers
67 views
Perform a constrained integration over $[-1,1]^6--yielding a “separability probability”
To begin with, I have a set of three positivity constraints (ensuring the positivity of a certain (twelve-parameter) $6 \times 6$ "density matrix", denoted in the standard manner as $\rho$, namely,
<...
0
votes
0answers
72 views
Approximate/estimate the ratio of two multidimensional constrained integrals
I have a hypothesis that a certain "qubit-qutrit separability probability" should assume the value $\frac{5}{3} \left(112 \pi ^2-1105\right) \approx 0.659488$. In its initial formulation, this is a ...
2
votes
3answers
208 views
Compute a certain “separability probability” via a constrained 4D integration over $[-1,1]^4$
I have employed the GenericCylindricalDecomposition command (applied to $6 \times 6$ "density matrix" positivity constraints) to compute the following expression
...
1
vote
2answers
74 views
Trouble finding a maximum of a constrained multivariate function
I have a multivariate function that I seek to maximize (ideally symbolically):
The function has the form:
$\frac{(-j*a)}{8 (-(b/2) - j (c-d-e)) ((j*b*c)/2 - (j*b*d)/2 + c*d - d^2 + a^2/4))}$
(...
4
votes
3answers
213 views
Cutting a section from a sphere by planes
I want to plot and find out the section of a sphere remaining after putting constraints in terms of cartesian planes. How it can be done?
For example, if I have a sphere of $r = 1$, and I put the ...
0
votes
1answer
59 views
Guarantee a positive value for $a$ when using SolveAlways [closed]
SolveAlways[y - 3 - 4*(x - 1) == a*x + b*y + c, {x, y}]
{{a -> -4, b -> 1, c -> 1}}
But if I want to get the ...
1
vote
2answers
51 views
Define x as a multiple of a number as a constraint in the Maximize function
I am trying to optimize a linearly constrained Production Function. I have three inputs and want them all to be multiples of 150. I can make all the inputs to belong to the Integer Domain but is there ...
2
votes
1answer
75 views
Why is Reduce in Mathematica giving solution in other symbols that don't exist in original equation [closed]
Here is an example:
Reduce[P/Q < (P - X)/(Q - X) && X > 0 && P > 0 && Q > 0 && P > Q, {X}, Integers]
The solution ...
0
votes
1answer
83 views
Need a package to compute constraint structure
I want to compute constraint structure of some field theory and some gravitational field theory. By constraint structure I mean what is explained in the "Lectures on Quantum Mechanics" by P. A. M. ...
3
votes
0answers
56 views
How can I prevent ParallelTable[] from freezing?
I have spent some time trying to figure this out.
I have a function that appears to be the reason my program is freezing. I am using both MemoryConstrained[] and <...
0
votes
1answer
82 views
Symmetric solution of ODE
Is it possible to force DSolve to calculate the symmetric solution?
Obviously the ode x''[t] + x[t] == 0 has the symmetric solution ...
2
votes
2answers
139 views
“Forcing output of a function to be Real in Mathematica” Non-linear optimization
I am trying to solve a Nonlinear optimization problem with Mathematica. Since the maximization problem includes exponentiation with fractional power, the result generates the complex numbers that stop ...
2
votes
1answer
147 views
Intersection Mathematica and SMT
recently i started to investigate in SMT-solvers (SAT Modulo Theory), especially Z3. My interest is in using it as a constraint solver on mixed integer/boolean problems, with a spoonful of SAT. I am ...
3
votes
0answers
126 views
How to define a constraint implying covariant derivatives in XTensor/XAct?
I have two manifolds: M and M1 with metrics g and g1.
...
1
vote
1answer
29 views
Finding smallest domain within which variables can satisfy inequality
Given an arbitrary number of variables $\epsilon_i$ that can be picked from a domain $[0, W]$ and some inequality relation between all the variables $G(\epsilon_1, \epsilon_2, ...)$, is there some way ...
1
vote
1answer
122 views
Increasing accuracy of solving overdetermined linear system
I am given $48 \times 48$ matrix $A$ and a vector $b$ and I would like to solve system $Ax = b$. I know that $A$ is underdetermined, i.e. there exist many solutions for $x$. Due to some considerations,...
0
votes
2answers
418 views
Using Assuming for conditional expression in Solve
When I solve the following equation I obtain a solution with a conditional expression
Solve[{0 == k Sin[x - y] - Sin[x], 0 == k Sin[y - x] - Sin[y]}, {x,y}]
How ...
