# \#displays-results **URL:** https://discuss.ampl.com/tag/displays-results/6.md [Latest](https://discuss.ampl.com/latest.md) · [Categories](https://discuss.ampl.com/categories.md) · [Tags](https://discuss.ampl.com/tags.md) --- ## [Interpreting presolve output](https://discuss.ampl.com/t/interpreting-presolve-output/2215)
**Author:** [@\_nr](https://discuss.ampl.com/u/_nr)\ **Replies:** 4\ **Last updated:** [January 19, 2026, 2:16am UTC](https://discuss.ampl.com/t/interpreting-presolve-output/2215 "2026-01-19T02:16:57Z")
How should I interpret the output of show\_stats with respect to the original model (the one prior to the presolve step)? I’m trying to understand the meaning behind the number of eliminated variables and constraints rep… --- ## [Comparing computational times across solvers (Gurobi, IPOPT, Knitro) in AMPL](https://discuss.ampl.com/t/comparing-computational-times-across-solvers-gurobi-ipopt-knitro-in-ampl/2187)
**Author:** [@salvapinedam](https://discuss.ampl.com/u/salvapinedam)\ **Replies:** 3\ **Last updated:** [September 9, 2025, 6:15pm UTC](https://discuss.ampl.com/t/comparing-computational-times-across-solvers-gurobi-ipopt-knitro-in-ampl/2187 "2025-09-09T18:15:32Z")
Hi all, We are running a set of experiments using AMPL with different solvers: Gurobi, IPOPT, and Knitro. Our goal is to benchmark their performance on a common problem. However, we are running into difficulties when tr… --- ## [Execution and memory load time for large-scale AMPL model using CPLEX](https://discuss.ampl.com/t/execution-and-memory-load-time-for-large-scale-ampl-model-using-cplex/2161)
**Author:** [@LauraSalcedo](https://discuss.ampl.com/u/LauraSalcedo)\ **Replies:** 3\ **Last updated:** [June 16, 2025, 5:04pm UTC](https://discuss.ampl.com/t/execution-and-memory-load-time-for-large-scale-ampl-model-using-cplex/2161 "2025-06-16T17:04:41Z")
We are working with a large-scale model and would like to know the estimated memory load time required for AMPL to process it properly. Additionally, we are interested in the resolve time and the total execution time of … --- ## [How can i solve this error?](https://discuss.ampl.com/t/how-can-i-solve-this-error/2108)
**Author:** [@edy\_munguambe](https://discuss.ampl.com/u/edy_munguambe)\ **Replies:** 1\ **Last updated:** [April 2, 2025, 1:18am UTC](https://discuss.ampl.com/t/how-can-i-solve-this-error/2108 "2025-04-02T01:18:58Z")
Trabalho.mod, line 36 (offset 1790): syntax error context: var \>\>\> z1:sum{ \<\<\< i in I} E\[i\] \* Z\[i\] + sum{l in L} F\[l\] \* W\[l\] + sum{i in I,k in K,j in J} (A\[j\] + B\[j\] \* t\_ik\[i,k\]) \* X\[i,k,j\] + sum{k in K,l in L,j in J}… --- ## [Decimal display](https://discuss.ampl.com/t/decimal-display/2067)
**Author:** [@dmorill](https://discuss.ampl.com/u/dmorill)\ **Replies:** 1\ **Last updated:** [February 24, 2025, 3:38pm UTC](https://discuss.ampl.com/t/decimal-display/2067 "2025-02-24T15:38:36Z")
Hello community, I have an issue displaying the results, and I hope you can help me. I have a MILP model with two binary variables (y, w) and one continuous variable (x). Despite using the command: option cplex\_options… --- ## [Downloading info to excel](https://discuss.ampl.com/t/downloading-info-to-excel/2029)
**Author:** [@Laura\_Rodriguez](https://discuss.ampl.com/u/Laura_Rodriguez)\ **Replies:** 1\ **Last updated:** [January 14, 2025, 6:57pm UTC](https://discuss.ampl.com/t/downloading-info-to-excel/2029 "2025-01-14T18:57:24Z")
Hello eveybody. I would like to automatically download my results from the AMPL console to and excel spreadsheet or a .csv but im not familiar with the way i can do it. If someone can provide further info I’d appreciate… --- ## [Syntax error in for loop](https://discuss.ampl.com/t/syntax-error-in-for-loop/1222)
**Author:** [@Bastian22](https://discuss.ampl.com/u/Bastian22)\ **Replies:** 2\ **Last updated:** [October 4, 2024, 3:29pm UTC](https://discuss.ampl.com/t/syntax-error-in-for-loop/1222 "2024-10-04T15:29:24Z")
Hello there! I’m trying to solve the multiobjective knapsack problem using the weighted sum method, but I have problem with the for bucle, I get the error “Syntax error”, but I can’t notice the reason. I suspect that t… --- ## [Trouble creating solution table and writing to Excel](https://discuss.ampl.com/t/trouble-creating-solution-table-and-writing-to-excel/1049)
**Author:** [@Abendrot47](https://discuss.ampl.com/u/Abendrot47)\ **Replies:** 1\ **Last updated:** [April 16, 2024, 3:45pm UTC](https://discuss.ampl.com/t/trouble-creating-solution-table-and-writing-to-excel/1049 "2024-04-16T15:45:45Z")
set SURGERY; set ROOM; param tour \> 0 integer; var Assign{SURGERY, ROOM, 1..tour} binary; table assignment OUT "amplxl" "3D" "sol.xlsx": {SURGERY, ROOM, 1..tour} -\> \[s ~ SURGERY, r ~ ROOM, t~TOUR\], Assign\[s,r,t\];… --- ## [Amplpy solve time Job shop scheduling](https://discuss.ampl.com/t/amplpy-solve-time-job-shop-scheduling/1020)
**Author:** [@icey](https://discuss.ampl.com/u/icey)\ **Replies:** 2\ **Last updated:** [March 26, 2024, 4:15pm UTC](https://discuss.ampl.com/t/amplpy-solve-time-job-shop-scheduling/1020 "2024-03-26T16:15:34Z")
Hello, I am modeling a job shop scheduling problem and want to evaluate the performance of different models in AMPL / AMPLPY. The AMPL solver finds the solution pretty quickly, but unless i set a time limit, it will tr… --- ## [Access Gurobi Work Time](https://discuss.ampl.com/t/access-gurobi-work-time/991)
**Author:** [@salvapineda](https://discuss.ampl.com/u/salvapineda)\ **Replies:** 1\ **Last updated:** [March 11, 2024, 8:20pm UTC](https://discuss.ampl.com/t/access-gurobi-work-time/991 "2024-03-11T20:20:33Z")
I’m solving a linear problem with amplpy and gurobi. As shown below, the work time (cpu time) required by Gurobi is 0.12 seconds. However, the times I get from ampl (solve\_time, etc) are different. Is there a way to acce… --- ## [Generate out files](https://discuss.ampl.com/t/generate-out-files/951)
**Author:** [@juan.carlos](https://discuss.ampl.com/u/juan.carlos)\ **Replies:** 1\ **Last updated:** [February 15, 2024, 12:27pm UTC](https://discuss.ampl.com/t/generate-out-files/951 "2024-02-15T12:27:57Z")
Hi, I’m using amplpy. How can I generate .out files instead of .sol files ? I can’t read the .sol files This is what I’m using in AMPL but I want to use it in AMPLPY: option solver cplex; option cplex\_options ‘timing… --- ## [Write Non-Zeros?](https://discuss.ampl.com/t/write-non-zeros/808)
**Author:** [@ubique2020](https://discuss.ampl.com/u/ubique2020)\ **Replies:** 1\ **Last updated:** [November 15, 2023, 6:27pm UTC](https://discuss.ampl.com/t/write-non-zeros/808 "2023-11-15T18:27:30Z")
Is there syntax for writing only non-zero values to a database file from the solution? I can’t figure it out from the documentation. --- ## [GCG save the chosen Dantzig Wolfe decomposition structure](https://discuss.ampl.com/t/gcg-save-the-chosen-dantzig-wolfe-decomposition-structure/665)
**Author:** [@L\_Essam](https://discuss.ampl.com/u/L_Essam)\ **Replies:** 1\ **Last updated:** [August 1, 2023, 9:51pm UTC](https://discuss.ampl.com/t/gcg-save-the-chosen-dantzig-wolfe-decomposition-structure/665 "2023-08-01T21:51:52Z")
Hi, I am solving an MILP model using GCG. Initially I let the solver try various decomposition structures on a small instance until the best structure is obtained. This process takes sometime. The output prints: Chosen … --- ## [Presolve Infeasibility warning in IPOPT solver](https://discuss.ampl.com/t/presolve-infeasibility-warning-in-ipopt-solver/622)
**Author:** [@Monish\_Kumar](https://discuss.ampl.com/u/Monish_Kumar)\ **Replies:** 17\ **Last updated:** [July 13, 2023, 5:08pm UTC](https://discuss.ampl.com/t/presolve-infeasibility-warning-in-ipopt-solver/622 "2023-07-13T17:08:51Z")
Warning: presolve: constraint nod\_SiSf cannot hold: body \>= 0 cannot be \<= -0.000123621; difference = 0.000123621 I need to expand this constraint to see what is the reason for infeasibility. I am not using console. A… --- ## [AMPL duplicate member "x" for set "y", how to fix it](https://discuss.ampl.com/t/ampl-duplicate-member-x-for-set-y-how-to-fix-it/474)
**Author:** [@Ares\_Inglada\_Grano](https://discuss.ampl.com/u/Ares_Inglada_Grano)\ **Replies:** 3\ **Last updated:** [April 6, 2023, 3:05pm UTC](https://discuss.ampl.com/t/ampl-duplicate-member-x-for-set-y-how-to-fix-it/474 "2023-04-06T15:05:16Z")
I 'm working with AMPL. In the “.mod” I have declared a set like this: set path\_intersections; It consists of rows of two numbers, the first one is the number of the path, and the second one the number of the intersectio… --- ## [Solutions pool (not optimal)](https://discuss.ampl.com/t/solutions-pool-not-optimal/446)
**Author:** [@juan.carlos](https://discuss.ampl.com/u/juan.carlos)\ **Replies:** 3\ **Last updated:** [March 27, 2023, 5:10pm UTC](https://discuss.ampl.com/t/solutions-pool-not-optimal/446 "2023-03-27T17:10:19Z")
Hi, Posted the same question in the Google group yesterday: I’m trying to generate a pool with optimal solutions. However, after executing my model for 8 hours, I didn’t find an optimal solution. The solution I found … --- ## [How to demonstrate the calculation process and progress of the solver LINDOGlobal](https://discuss.ampl.com/t/how-to-demonstrate-the-calculation-process-and-progress-of-the-solver-lindoglobal/443)
**Author:** [@LealzzzZZZ](https://discuss.ampl.com/u/LealzzzZZZ)\ **Replies:** 4\ **Last updated:** [March 22, 2023, 4:55pm UTC](https://discuss.ampl.com/t/how-to-demonstrate-the-calculation-process-and-progress-of-the-solver-lindoglobal/443 "2023-03-22T16:55:23Z")
How to demonstrate the calculation process and progress of the solver LINDOGlobal. The calculation process for most problems is time-consuming and the calculation progress cannot be mastered. --- ## [Solution with and without presolve is different - can this behavior be expected?](https://discuss.ampl.com/t/solution-with-and-without-presolve-is-different-can-this-behavior-be-expected/335)
**Author:** [@ChristianHoffmann](https://discuss.ampl.com/u/ChristianHoffmann)\ **Replies:** 1\ **Last updated:** [January 24, 2023, 1:22am UTC](https://discuss.ampl.com/t/solution-with-and-without-presolve-is-different-can-this-behavior-be-expected/335 "2023-01-24T01:22:24Z")
Hello, I have solved a simulation problem with AMPL (objective function = 1) with presolve = on, CONOPT presolve = off, CONOPT presolve = on, IPOPT presolve = off, IPOPT In three cases, I obtain a solution that makes … --- ## [Nothing is displayed in console](https://discuss.ampl.com/t/nothing-is-displayed-in-console/143)
**Author:** [@Mampenda](https://discuss.ampl.com/u/Mampenda)\ **Replies:** 1\ **Last updated:** [November 24, 2022, 12:27pm UTC](https://discuss.ampl.com/t/nothing-is-displayed-in-console/143 "2022-11-24T12:27:11Z")
I have tried to solve a simple minimization problem in AMPL like so: .mod: set PARTS; # set of parts we can produce set MACHINES; # set of machines that produces parts param cap {MACHINES} \>= 0; # capacity of prod… --- ## [How can I look at the explicit constraints that AMPL has generated from my model and data?](https://discuss.ampl.com/t/how-can-i-look-at-the-explicit-constraints-that-ampl-has-generated-from-my-model-and-data/55)
**Author:** [@megrobert](https://discuss.ampl.com/u/megrobert)\ **Replies:** 0\ **Last updated:** [December 15, 2021, 5:30pm UTC](https://discuss.ampl.com/t/how-can-i-look-at-the-explicit-constraints-that-ampl-has-generated-from-my-model-and-data/55 "2021-12-15T17:30:31Z")
AMPL’s expand command can display any explicit linear constraint, or indexed collection of constraints. For example: ampl: model transp.mod; ampl: data transp.dat; ampl: expand Demand\['STL'\]; s.t. Demand\['STL'\]: … --- ## [How do I list all variables that have a certain property in the optimal solution?](https://discuss.ampl.com/t/how-do-i-list-all-variables-that-have-a-certain-property-in-the-optimal-solution/54)
**Author:** [@megrobert](https://discuss.ampl.com/u/megrobert)\ **Replies:** 0\ **Last updated:** [December 15, 2021, 5:29pm UTC](https://discuss.ampl.com/t/how-do-i-list-all-variables-that-have-a-certain-property-in-the-optimal-solution/54 "2021-12-15T17:29:20Z")
The built-in parameter \_nvars contains the number of variables; a symbolic parameter \_varname\[j\] contains the AMPL name of the j th variable; and \_var\[j\] is a “synonym” that refers to the j th variable. Thus to show the … --- ## [How do I get “ranges” and other sensitivity analyses?](https://discuss.ampl.com/t/how-do-i-get-ranges-and-other-sensitivity-analyses/53)
**Author:** [@megrobert](https://discuss.ampl.com/u/megrobert)\ **Replies:** 0\ **Last updated:** [December 15, 2021, 5:27pm UTC](https://discuss.ampl.com/t/how-do-i-get-ranges-and-other-sensitivity-analyses/53 "2021-12-15T17:27:36Z")
AMPL’s suffix feature can be used by solvers to return ranging information. See in particular the discussion of solver-defined suffixes in Section 14.3 of the AMPL book for an example of range output from CPLEX. The opti… --- ## [How do I get a “tableau column” from AMPL?](https://discuss.ampl.com/t/how-do-i-get-a-tableau-column-from-ampl/52)
**Author:** [@megrobert](https://discuss.ampl.com/u/megrobert)\ **Replies:** 0\ **Last updated:** [December 15, 2021, 5:27pm UTC](https://discuss.ampl.com/t/how-do-i-get-a-tableau-column-from-ampl/52 "2021-12-15T17:27:08Z")
AMPL cannot determine by itself the values from the linear programming tableau, because the sparse linear algebra routines capable of computing these values are found only in the solvers. Efficient solver implementations… --- ## [Why can’t I view an indexed collection of subsets by typing display {k in SS} POW\[k\]?](https://discuss.ampl.com/t/why-can-t-i-view-an-indexed-collection-of-subsets-by-typing-display-k-in-ss-pow-k/51)
**Author:** [@megrobert](https://discuss.ampl.com/u/megrobert)\ **Replies:** 0\ **Last updated:** [December 15, 2021, 5:26pm UTC](https://discuss.ampl.com/t/why-can-t-i-view-an-indexed-collection-of-subsets-by-typing-display-k-in-ss-pow-k/51 "2021-12-15T17:26:39Z")
The display command does not currently recognize {k in SS} POW\[k\] where POW is an indexed (subscripted) set. For this elementary case, you can exhibit the whole indexed collection of subsets by giving just the name of th… --- ## [How can I get the display command to list a set’s members in the same order that they were given in my data file?](https://discuss.ampl.com/t/how-can-i-get-the-display-command-to-list-a-set-s-members-in-the-same-order-that-they-were-given-in-my-data-file/50)
**Author:** [@megrobert](https://discuss.ampl.com/u/megrobert)\ **Replies:** 0\ **Last updated:** [December 15, 2021, 5:25pm UTC](https://discuss.ampl.com/t/how-can-i-get-the-display-command-to-list-a-set-s-members-in-the-same-order-that-they-were-given-in-my-data-file/50 "2021-12-15T17:25:46Z")
Add the keyword ordered to the set’s declaration, after the set name. It can be useful to declare a set ordered for purposes of ordering the output, even when the ordering plays no role in the model. --- ## [Where do I find the amount of computation (CPU) time taken by AMPL or by a solver?](https://discuss.ampl.com/t/where-do-i-find-the-amount-of-computation-cpu-time-taken-by-ampl-or-by-a-solver/49)
**Author:** [@megrobert](https://discuss.ampl.com/u/megrobert)\ **Replies:** 0\ **Last updated:** [December 15, 2021, 5:25pm UTC](https://discuss.ampl.com/t/where-do-i-find-the-amount-of-computation-cpu-time-taken-by-ampl-or-by-a-solver/49 "2021-12-15T17:25:13Z")
AMPL provides the following built-in timing parameters such as \_ampl\_time and \_total\_solve\_time . You’ll find the complete list in Table A-14 in the reference appendix of the AMPL book. These timing parameters can be use…