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POlpsolve solves the integer linear programming without meeting the given constraints
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copied!<p>I am wondering whether any one here uses lpsolve to solve linear programming problem.</p> <p>I have defined a integer linear programming problem in a file where there is a constraint x45=0(there are also other integer variables). After the problem is solved by lpsolve, the result reported strangely is x45=1. However, if I put a label before the constraint, for example, c1:x45=0, then the constraint will be met. Anyone here know what's going on?</p> <p>So the problem I defined in my LP file is like:</p> <pre><code>max: 0 x0 262 x1 262 x2 262 x3 262 x4 262 x5 262 x6 262 x7 270 x8 0 x9 270 x10 270 x11 270 x12 270 x13 270 x14 270 x15; 549 x16 549 x17 0 x18 549 x19 549 x20 549 x21 549 x22 549 x23 >= 1; 603 x24 603 x25 603 x26 0 x27 603 x28 603 x29 603 x30 603 x31 >= 1; x0=0; x9=0; x18=0; x27=0; x36=0; x45=0; x54=0; x63=0; x0=x0; x1=x8; x2=x16; x3=x24; x4=x32; x5=x40; x6=x48; x7=x56; x8=x1; x9=x9; x10=x17; x11=x25; x12=x33; x13=x41; x14=x49; x15=x57; x16=x2; x17=x10; x18=x18; x19=x26; x20=x34; x21=x42; x22=x50; x23=x58; x24=x3; x25=x11; x26=x19; x27=x27; x28=x35; x29=x43; x30=x51; x31=x59; x32=x4; x33=x12; x34=x20; x35=x28; x36=x36; x37=x44; x38=x52; x39=x60; x40=x5; x41=x13; x42=x21; x43=x29; x44=x37; x45=x45; x46=x53; x47=x61; x48=x6; x49=x14; x50=x22; x51=x30; x52=x38; x53=x46; x54=x54; x55=x62; x56=x7; x57=x15; x58=x23; x59=x31; x60=x39; x61=x47; x62=x55; x63=x63; x0 x1 x2 x3 x4 x5 x6 x7=1; x8 x9 x10 x11 x12 x13 x14 x15=1; x16 x17 x18 x19 x20 x21 x22 x23=1; x24 x25 x26 x27 x28 x29 x30 x31=1; x32 x33 x34 x35 x36 x37 x38 x39=1; x40 x41 x42 x43 x44 x45 x46 x47=1; x48 x49 x50 x51 x52 x53 x54 x55=1; x56 x57 x58 x59 x60 x61 x62 x63=1; bin x0,x1,x2,x3,x4,x5,x6,x7,x8,x9,x10,x11,x12,x13,x14,x15,x16,x17,x18,x19,x20,x21,x22,x23,x24,x25,x26,x27,x28,x29,x30,x31,x32,x33,x34,x35,x36,x37,x38,x39,x40,x41,x42,x43,x44,x45,x46,x47,x48,x49,x50,x51,x52,x53,x54,x55,x56,x57,x58,x59,x60,x61,x62,x63; </code></pre> <p>By solving it, the result is:</p> <pre><code>Value of objective function: 532.00000000 Actual values of the variables: x0 0 x1 0 x2 0 x3 0 x4 0 x5 0 x6 0 x7 1 x8 0 x9 0 x10 1 x11 0 x12 0 x13 0 x14 0 x15 0 x16 0 x17 1 x18 0 x19 0 x20 0 x21 0 x22 0 x23 0 x24 0 x25 0 x26 0 x27 0 x28 1 x29 0 x30 0 x31 0 x36 0 x45 1 x54 1 x63 0 x32 0 x40 0 x48 0 x56 1 x33 0 x41 0 x49 0 x57 0 x34 0 x42 0 x50 0 x58 0 x35 1 x43 0 x51 0 x59 0 x37 0 x44 0 x38 0 x52 0 x39 0 x60 0 x46 0 x53 0 x47 0 x61 0 x55 0 x62 0 </code></pre> <p>As you can see. x45 and x54 are both 1 while other constraints are all met. If I put a lable before the constraint such as : </p> <pre><code>c1: x45=0; </code></pre> <p>Then it will be met. I am not sure why this makes a difference</p>

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