* This research supported by the GAMS Applied General Equilibrium Research Fund. The software described here operates only with GAMS 2.25.089 or later on the PC. The author remains responsible for any bugs which exist in this software. This software is not officially supported by GAMS Corporation.
On occasion it is necessary for GAMS programs to share data with GEMPACK programs. This document describes libinclude routines which facilitate the transfer of data to and from files in GEMPACK header array format, identified by the suffix ".HAR". Data transfers from GAMS into HAR files involve the GAMS2HAR libinclude routine and occur at execution time. Data transfers from HAR files into GAMS involve the HAR2GAMS libinclude routine and occur at compile time.
Element order in GAMS2HAR output files
The file inclib.pck contains all of the libinclude programs which have been developed at the University of Colorado during the past couple of years. These include files for report writing (GAMS2TBL), spreadsheet interface (SSLINK), workbook interface (XLLINK), and plotting (GNUPLOT). Libinclude source files for all of these applications are kept in a single archive in order to simplify maintenance. You may need to download additional batch and executable files in order to install these other packages.
$LIBINCLUDE gams2har [ file_prefix param1 domain1 param2 domain2 ...[&] ]Some additional information:
(i) gams2har only works for parameters.
(ii) The first invocation must be outside of a loop or if block.
(iii) In order to use the routine within a loop or if block, include a blank invocation (without arguments) to initialize.
(iv) Domain specifications are required, with a single set identifier for each dimension.
(v) Data is written to the header array file using the MODHAR. The data transfer occurs following each call to gams2har, provided that the call does not terminate with a continuation symbol, "&".
(vi) A continuation symbol indicates that additional parameters will be provided on a subsequent call.
$LIBINCLUDE har2gams filehar2gams reads all parameters from a specified header array file. It is not possible to read individual parameters from a header array file.
set i /i1*i3/; alias (i,j); parameter a(i,j) Parameter to write into HAR file; a(i,j) = uniform(0,1); $libinclude gams2har ex1 a i j display a;This code generates a file named ex1.har. The following program reads the resulting header array file:
set i /i1*i3/; alias (i,j); $libinclude har2gams ex1 display a;Both programs generate identical output:
---- 206 PARAMETER A Parameter to write into HAR file i1 i2 i3 i1 0.172 0.843 0.550 i2 0.301 0.292 0.224 i3 0.350 0.856 0.067
set i /i1*i3/; alias (i,j); parameter a(i,j) Matrix array to write into HAR file b(i) Vector array to write into HAR file; a(i,j) = uniform(0,1); b(i) = uniform(0,1); * Execute the data transfer with a continuation: $libinclude gams2har ex2 a i j b i display a,b;Alternatively, the second parameter could be transferred in a continuation line:
$libinclude gams2har ex2 a i j & $libinclude gams2har b i
This version also writes TABLO Input files which can be used (in conjunction with GEMPACK) to
The TAB files produced have names which start with the name of the output HAR file, followed by an underscore "_" and then a single letter. The letter at the end is "s" (declares and read sets), "c" (declares and reads Coefficients) and "w" (writes Coefficients).
For Example 2 (see above), the TAB files produced are EX2_S.TAB, EX2_C.TAB and EX2_W.TAB. They are as follows.
File BaseData # Contains set and coefficient data # ; Set i read elements from file Basedata header "s0001" ;
! Next is declared in SETS TAB file ! !File Basedata # Contains set and coefficient data # ;! Coefficient (All,i1,i)(All,i2,i) a(i1,i2) ; Read a from file Basedata header "h001" ; Coefficient (All,i1,i) b(i1) ; Read b from file Basedata header "h002" ;
Write a to terminal ; Write b to terminal ;
GEMPACK users should be careful about the order of the elements in the sets written on the output HAR file by GAMS2HAR. An example will make this clear.
Consider the following GAMS file HAR1.GMS.
SET Powerset / cap, inv, dep/ Misc miscellaneous data in DATA /sx, sh, cap, wb/ ; PARAMETER param1(powerset) param2(misc) ; param1(powerset)=23 ; param2(misc)=12 ; param2("cap") = 11 ; $LIBINCLUDE gams2har ex1 param2 misc
You might expect that the elements of the set Misc on the output HAR file EX1.HAR would be as in the declaration of the set Misc in HAR1.GMS. However, the order will be
cap, sx, sh, wb
since GAMS stores the element names in the order they appear in the whole file HAR1.GMS. Since "cap" appears in set Powerset, it comes before the other elements of Misc when written to EX1.HAR by GAMS2HAR.
Since the order of the elements can be important in interpreting data on HAR files, you should look carefully at the output HAR file. For this reason, GEMPACK users should consider including statement
check-on-read all = yes ;
in their Command files when reading data translated via GAMS2HAR to check that they are associating data correctly.
Economics Department, University of Colorado, Boulder CO 80309-0256
Phone: (303) 492-5169, Fax: (303) 492-8969
Create January, 2000 by TFR
Updated May, 2002 by TFR and KRP