Hi Achyu,

thank you for your question.

I would change the direction of the minimization objective. So if e.g. the objective to minimize is x1+x2, then change the direction to -x1-x2 and maximize it. In that way you could apply the same logic as in this article.

If you post an exemplary problem here, I will model and solve it for you.

]]>Hi Andrew.

Thank you for your nice feedback and good question. You need to proceed as follows:

1) Go to MapBox website and set up a user account

2) Create a map layout on the MapBox website

3) For the map you created you will get a token

4) in R, use the following line of code placing your token key instead of yourTokenString:

Sys.setenv(MAPBOX_API_TOKEN = yourTokenString)

Great blog you have, I would like to ask how did you add the mapbox_basemap?

I try with your code above in R and create a base map on mapbox, but R only showed the layer I add on but not the base map.

]]>Hi ahmed, this can be tricky. Can you provide an exemplary description of your optimization problem? Ideally, your code?

Here is some documentation that touches on your question theoretically: http://yetanothermathprogrammingconsultant.blogspot.com/2016/01/finding-all-optimal-lp-solutions.html

]]>Hi Andrew,

thanks for your comment.

You can try to formulate your problem as a linear optimization problem, from scratch. For example, the cost of holding inventory can be derived from the travel time, and the travel time depends on transportation distance (one variable) and transportation mode (binary or integer variable).

The objective of covering 90% of your forecast by truck could be formulated as a constraint, or maybe a better approach would be to define two objective functions, and to apply multi-goal linear programming.

If you provide some more info I might very well try to model it and post it, maybe in a simplified version!

BR

]]>I am trying to “go to the next level”.

I want to look deeper than this and say, “OK, truck A costs me $100 and takes 3 weeks, but flight A costs me $200 and takes just 1 week to move the good”

For me, i am still trying to move things from A to B, but now i am expanding it to try and look at the total cost of holding the inventory, reduction in cash flow and the cost of delivery. I want to “optimise” my transportation so that maybe 90% of my forecast is shipped via truck, then i can “top up” with the flight if demand requires.

Any suggestions how to approach this issue or where to turn for some guidance?

Thanks ]]>