ampl

问题 The following set and parameters are written in the AMPL environment. How can they be converted to CPLEX? set B; #set of all blocks set T; #set of time periods set BI{B}; #set of blocks that overlie a block set BY{T}; #set of blocks that can be excavated in time period t param C_min; #minimum processing capacity of a mill param g{B}; #average grade for block param x_cord{B}; #x-coordinate of a block param r{B} symbolic; param early{B} default 1; var alpha{B,T} binary; # indicator for which

问题 The following set and parameters are written in the AMPL environment. How can they be converted to CPLEX? set B; #set of all blocks set T; #set of time periods set BI{B}; #set of blocks that overlie a block set BY{T}; #set of blocks that can be excavated in time period t param C_min; #minimum processing capacity of a mill param g{B}; #average grade for block param x_cord{B}; #x-coordinate of a block param r{B} symbolic; param early{B} default 1; var alpha{B,T} binary; # indicator for which

问题 The following set and parameters are written in the AMPL environment. How can they be converted to CPLEX? set B; #set of all blocks set T; #set of time periods set BI{B}; #set of blocks that overlie a block set BY{T}; #set of blocks that can be excavated in time period t param C_min; #minimum processing capacity of a mill param g{B}; #average grade for block param x_cord{B}; #x-coordinate of a block param r{B} symbolic; param early{B} default 1; var alpha{B,T} binary; # indicator for which

问题 Is there any silent mode to run a AMPL script using CPLEX as a solver. I am sure the option option solver_msg 0; will make it silent but it still output CPLEX version number to the console. How can I make it totally silence. Because I think the console output will dramatically cost running time. 回答1: You can suppress all output by redirecting it to /dev/null (or NUL on Windows) in addition to setting solver_msg to 0: option solver_msg 0; solve > /dev/null; That said, most of the solver

问题 I have a sparse matrix in AMPL. As a result, it includes a lot of values that are coded as ".". The "." value in AMPL means "no value specified here." When I try to solve the optimization problem I get a message reading "no value specified for..." in reference to the cells containing the "." consequently, it won't solve the problem. However, when I try to specify a default value to replace the ".", the problem churns and churns and doesn't solve. Is there any way I can set restrictions on the

问题 I another bug as you can see below: Error at _cmdno 8 executing "solve" command (file ./script/runConfiguration.run, line 5, offset 127): error processing constraint c1a[2,'o1',1]: unexpected type 0x14205 in ecopy() I guess that the problem causing comparison with the index (element of set) variable in c1a constraint. Is it possible to avoid this bug? My new ampl model: #sets #------------------------------------------------------------------------------------- set K; #index of nodes with

问题 Is there a way to simplify declaring a tuple of parameters in AMPL ? For example, if a three-dimensional point was needed as a parameter, what I'm doing is declaring it as param Point {{'a', 'b', 'c'}}; and then accessing it through P['a'] , P['b'] , and P['c'] . The problem with this is, first, that it's ugly. To specify the point (1, 2, 3) in the data file you would have to write param Point := a 1 b 2 c 3; . I tried using the ordered keyword—i.e. param Point {{'a', 'b', 'c'} ordered}; —so

问题 I have an equation and i don't know how to implement it in AMPL for CPLEX. Here is it: enter image description here Thank you for your help! 回答1: With a linear solver (like CPLEX), the usual approach is to turn this into a linear constraint with a binary variable indicating which of the two cases applies. param eps; param beta; param bignum = 1e5; var z_s_1 binary; # will have value 0 when z_v <= eps, else 1 var z_s = z_s_1*beta; var z_v >= 0; s.t. Define_z_s_1_a: z_s_1 * eps <= z_v; # so if

问题 In AMPL, I have a set which should store some similar values. But I have a "duplicate number" error. Is there any way to do that? What is the simplest method to solve this problem? The set is: set A; data: set A := 1 1 2; Thanks 回答1: Set elements should be unique in AMPL. To store duplicate values use parameter instead: set S; param A{S}; data; param: S: A := 1 1 2 1 3 2; 来源： https://stackoverflow.com/questions/26739400/ampl-error-duplicate-number-for-set

问题 suppose we have the following ampl model: set objects; set sacks; ... var Take{objects, sacks} binary; ... display Take; after solving the optimization problem I want to display only the lines of Take that equal 1 回答1: You can do something like this: for{o in objects, s in sacks: Take[o,s] = 1} { printf "\n %s %s", o,s; } 来源： https://stackoverflow.com/questions/49281515/ampl-display-variable-depending-on-a-condition