[Help-glpk] Can GLPK for JAVA solve multi-objective optimization
Hi! I have an objective function described as following, which is lineal: [cid:image005.png@01CC484D.FB6B32D0] The optimized variables are [cid:image003.png@01CC502C.5A6B0D10] , which are integers in [0, 10], [cid:image004.png@01CC502C.5A6B0D10]is a lineal function of [cid:image003.png@01CC502C.5A6B0D10] an[cid:image006.png@01CC502C.5A6B0D10] [cid:image007.png@01CC502C.5A6B0D10], and [cid:image008.png@01CC502C.5A6B0D10] And W is a weight value. Can I use GLPK for JAVA to get the optimized results? If it is possible, could you give me an example? Thank you in advance, Yi Zong Scientist Intelligent Energy Systems Technical University of Denmark [cid:image002.gif@01CC484B.D8C57CB0] Risø National Laboratory for Sustainable Energy Frederiksborgvej 399, Building 776 4000 Roskilde Direct +45 4677 5045 y...@risoe.dtu.dkmailto:d...@risoe.dtu.dk www.risoe.dtu.dkhttp://www.risoe.dtu.dk/ inline: image001.gifinline: image002.gifinline: image005.pnginline: image007.pnginline: image014.pnginline: image015.pnginline: image016.pnginline: image017.pnginline: image003.pnginline: image004.pnginline: image006.pnginline: image007.pnginline: image008.png___ Help-glpk mailing list Help-glpk@gnu.org https://lists.gnu.org/mailman/listinfo/help-glpk
Re: [Help-glpk] implementing constraints in Scala
How can I print hole model, objective + constrains ?
Set the uper bount to infinity and get uper/lower bount of a variable?
On Sun, Jul 31, 2011 at 6:58 PM, glpk xypron xypron.g...@gmx.de wrote:
Hello Onor,
for (i - 0 to col.size-1) {
GLPK.glp_set_obj_coef(lp, i,coef(i))
}
if you have n columns, GLPK number these 1 to n. You possibly
wanted to write:
GLPK.glp_set_obj_coef(lp, i + 1,coef(i))
Cf. sample.c on page 15 of glpk-4.45/doc/glpk.pdf
GLPK.glp_set_col_bnds(lp, colId+1, GLPKConstants.GLP_LO, 0,1000)
The number 1000 will be ignored.
The lower bound will be set to 0.
Best regards
Xypron
Original-Nachricht
Datum: Sun, 31 Jul 2011 16:07:01 +0200
Betreff: Re: [Help-glpk] implementing constraints in Scala
thank you very much I have some more question
there is a problem I got no solution and i dont knew why.
Could you tell me in which function(s) is the problem?
the contraints I did as you told me. I change only GLP_UP; FX
startModelBuilding(nbRows : Int, nbCols : Int){
lp = GLPK.glp_create_prob()
GLPK.glp_add_cols(lp, nbCols)
}
def setBounds(colId : Int, low : Double, up : Double) {
GLPK.glp_set_col_bnds(lp, colId+1, GLPKConstants.GLP_DB, low, up)
}
def setUnboundUpperBound(colId : Int) {
GLPK.glp_set_col_bnds(lp, colId+1, GLPKConstants.GLP_LO, 0,1000)
}
def addObjective(coef : Array[Double], col : Array[Int], minMode :
Boolean = true) {
GLPK.glp_set_obj_name(lp, objective);
GLPK.glp_set_obj_dir(lp, if (minMode) GLPKConstants.GLP_MIN else
GLPKConstants.GLP_MAX)
for (i - 0 to col.size-1) {
GLPK.glp_set_obj_coef(lp, i,coef(i))
}
}
def solveModel() : Int = {
println(solveModel);
val iocp = new glp_iocp();
GLPK.glp_init_iocp(iocp);
iocp.setPresolve(
GLPKConstants.GLP_ON);
val ret = GLPK.glp_intopt(lp, iocp);
if (ret == 0) {
sol = Array.tabulate(nbCols)(col = GLPK.glp_mip_col_val(lp,col
+1))
objectiveValue = GLPK.glp_mip_obj_val(lp)
ret
} else {
System.out.println(The problem could not be solved);
ret
--
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Re: [Help-glpk] implementing constraints in Scala
Hello Onor, you can save the whole model to a file (using glp_write_lp() or glp_write_prob()) and then print the file. When you use glp_set_col_bnds() or glp_set_row_bnds to set the lower bound (GLP_LO), the upper bound is set to infinity. You can use glp_get_row_lb(), glp_get_row_ub(), glp_get_col_lb(), glp_get_col_ub() for retrieving the bounds. Please, study glpk-4.45/doc/glpk.pdf available in the source distribution of GLPK: ftp://ftp.gnu.org/gnu/glpk/glpk-4.45.tar.gz Best regards Xypron. On 01.08.2011 10:26, name name wrote: How can I print hole model, objective + constrains ? Set the uper bount to infinity and get uper/lower bount of a variable? ___ Help-glpk mailing list Help-glpk@gnu.org https://lists.gnu.org/mailman/listinfo/help-glpk
Re: [Help-glpk] Can GLPK for JAVA solve multi-objective optimization
Hello Yi, yes you can do the optimization with GLPK for Java. Please, study the examples files provided with GLPK for Java, e.g. glpk-java-1.0.15/examples/java/Mip.java You can download the source of GLPK for Java from http://glpk-java.sourceforge.net. For the documentation of the GLPK API, please, read glpk-4.45/doc/glpk.pdf available in the source distribution of GLPK ftp://ftp.gnu.org/gnu/glpk/glpk-4.45.tar.gz Best regards Xypron On 01.08.2011 09:21, Zong, Yi wrote: Hi! I have an objective function described as following, which is lineal: The optimized variables are , which are integers in [0, 10], is a lineal function of an , and And W is a weight value. Can I use GLPK for JAVA to get the optimized results? If it is possible, could you give me an example? Thank you in advance, Yi Zong Scientist Intelligent Energy Systems Technical University of Denmark Ris National Laboratory for Sustainable Energy Frederiksborgvej 399, Building 776 4000 Roskilde Direct +45 4677 5045 y...@risoe.dtu.dk www.risoe.dtu.dk ___ Help-glpk mailing list Help-glpk@gnu.org https://lists.gnu.org/mailman/listinfo/help-glpk ___ Help-glpk mailing list Help-glpk@gnu.org https://lists.gnu.org/mailman/listinfo/help-glpk
[Help-glpk] [Fwd: [Fwd: Re: Initializing a few decision variables]]
Forwarded Message
From: mgoet...@isye.gatech.edu
To: help-glpk@gnu.org
Subject: [Fwd: Re: [Help-glpk] Initializing a few decision variables]
Date: Mon, 1 Aug 2011 12:00:38 -0400
I added two arrays of equal dimensions to the set, FT and FS, and
initialized them in the data section
They hold the paired values for the initial assignments.
set FT :=D1 B2 D2 B3 B1;
set FS := 1 2 4 5 7;
I added the following statement to the model
s.t. init{f in FT,}: x[f,FS[f]] = 1;
the error is that FS cannot be subscripted.
Basic question remains on how to specify the initial assignment constraint
in the model section
and how to specify the pairs of initial assigments in the data section.
Thanks
if B1 is a set, you probably want to write:
s.t. {b in B1} c1 : x[b,21] = 1;
# or
s.t. c2 : x[b,21] = 1; # where b is a member of B1
Best regards
Xypron
On 29.07.2011 16:45, Marc Goetschalckx wrote:
I am using a model coded in GMPL.
The model has a large two-dimensional array of x variables, one
dimension has literal indices that are defined in a set in the data
segment (example is B1)
This model is running and solving so far.
However, I need to initialize a very few of the x variables because of
boundary conditions.
Statement in the model section is similar to
s.t. x[B1,21]=1;
This cannot be done because B1 is not yet defined (from the data
section).
How can I initialize some of the variables in the data section, or
what is the sequence of actions that can achieve this.
Thanks.
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Re: [Help-glpk] [Fwd: [Fwd: Re: Initializing a few decision variables]]
I added two arrays of equal dimensions to the set, FT and FS, and
initialized them in the data section
They hold the paired values for the initial assignments.
set FT :=D1 B2 D2 B3 B1;
set FS := 1 2 4 5 7;
I added the following statement to the model
s.t. init{f in FT,}: x[f,FS[f]] = 1;
the error is that FS cannot be subscripted.
Basic question remains on how to specify the initial assignment constraint
in the model section
and how to specify the pairs of initial assigments in the data section.
In the model section:
set F, dimen 2;
s.t. init{(i,j) in F}: x[i,j] = 1;
In the data section:
set F := D1 1, B2 2, D2 4, B3 5, B1 7;
Please see also examples included in glpk distribution.
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