Dear Loan,

You might want to place a lower bound equal to a small positive number on all variables that you raise to a power.

Frank Ward

From: gamsworld@googlegroups.com [mailto:gamsworld@googlegroups.com] On Behalf Of ltloan@hcmuaf.edu.vn

Sent: Friday, June 28, 2013 10:32 AM

To: gamsworld@googlegroups.com

Subject: GRAD SINGULAR error

Dear all:

Can anyone help me to correct the error below. In my GAMS code, I wrote the production functions, for example:

QINT_G2(I)… QINT(I,‘G2’) =L= (QQINT(I,‘G1’,‘G2’)**DELTA_INT(I,‘G1’,‘G2’))*(QQINT(I,‘G2’,‘G2’)**DELTA_INT(I,‘G2’,‘G2’))

*(QQINT(I,‘G3’,‘G2’)**DELTA_INT(I,‘G3’,‘G2’))*(QQINT(I,‘G4’,‘G2’)**DELTA_INT(I,‘G4’,‘G2’))

*(QQINT(I,‘G6’,‘G2’)**DELTA_INT(I,‘G6’,‘G2’))*(QQINT(I,‘G7’,‘G2’)**DELTA_INT(I,‘G7’,‘G2’));

I have corrected by replacing the power function, but the error has not been solved.

Could you please help me to correct this error?

Thank you so much

Loan

My errors:

**** ERRORS/WARNINGS IN EQUATION QP_BIO

10 warning(s): vcPower: GRAD SINGULAR: x**c, x=0, 0<c<1

**** ERRORS/WARNINGS IN EQUATION QFUELS_G6

10 warning(s): vcPower: GRAD SINGULAR: x**c, x=0, 0<c<1

**** ERRORS/WARNINGS IN EQUATION QINT_G2(VNM)

30 warning(s): vcPower: GRAD SINGULAR: x**c, x=0, 0<c<1

**** ERRORS/WARNINGS IN EQUATION QINT_G4(VNM)

30 warning(s): vcPower: GRAD SINGULAR: x**c, x=0, 0<c<1

**** ERRORS/WARNINGS IN EQUATION QINT_G6(VNM)

25 warning(s): vcPower: GRAD SINGULAR: x**c, x=0, 0<c<1

**** ERRORS/WARNINGS IN EQUATION PRO_Q2(VNM)

20 warning(s): vcPower: GRAD SINGULAR: x**c, x=0, 0<c<1

**** ERRORS/WARNINGS IN EQUATION PRO_Q4(VNM)

20 warning(s): vcPower: GRAD SINGULAR: x**c, x=0, 0<c<1

**** ERRORS/WARNINGS IN EQUATION PRO_Q6_VNM

20 warning(s): vcPower: GRAD SINGULAR: x**c, x=0, 0<c<1

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