Invalid Floating point error

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Author Message   Jay Bala (jay) New member Username: jay Post Number: 1 Registered: 02-2008 Posted on Sunday, February 03, 2008 - 01:40 am:    Hi, I am trying to solve two peds to calculate the Xe concentration and reactivity from it. but encountring "Invalid floating point error" Could you please help me. Thank you. Reactivity calculation xe.pde (0.9 k)   Marek Nelson (mgnelson) Moderator Username: mgnelson Post Number: 19 Registered: 07-2007 Posted on Sunday, February 03, 2008 - 02:35 pm:    1) You are getting this error because you have defined your coordinates as Cartesian2 but have only defined a line as your region. In 2D, you need to define some area as your region. Or define your coordinates as Cartesian1. 2) Your equations have no spatial dependence. So a HISTORY is the only plot that will give any information, and you don't need many cells, so SELECT NGRID=1 will limit the number of cells. 3) The entire reaction is over by time 1. So you should change your time interval accordingly. See the attached script. xe1.pde (1.1 k)   Jay Bala (jay) New member Username: jay Post Number: 2 Registered: 02-2008 Posted on Monday, February 04, 2008 - 01:21 am:    Thank you. I actually used cartesian1 (1D I entered the wrong lambda values, it should be lambda_i = 0.1035 lambda_Xe = 0.0753 That fixed the timing problem, and gave expected answers. I used the time interval of 1-100 hr. Thank you for the help. I really appreciate it.   Jay Bala (jay) Junior Member Username: jay Post Number: 3 Registered: 02-2008 Posted on Monday, February 04, 2008 - 06:11 pm:    Hi, Is there anyway i can find out the exact time when the concentration peaks and exact value of it. I tried Time_Max but i don't think i am getting it right. Thank you   Marek Nelson (mgnelson) Moderator Username: mgnelson Post Number: 20 Registered: 07-2007 Posted on Monday, February 04, 2008 - 07:09 pm:    TIME_MAX() is a function that takes a scalar (single numeric value) argument and returns the maximum value seen during the run. So you cannot take the TIME_MAX of a variable directly. In order to get the time max of a variable, you also need to use the GLOBALMAX() or VAL(). i.e. You can modify your history plot : HISTORY (Xe) at (1/2,1/2) REPORT (TIME_MAX(GLOBALMAX(Xe))) This will printout the value at the bottom of the history. At present, there is no way to get the time at which this maximum was reached. You will have to read it from the history plot. That was an oversight on our part and we intend to add it soon (the TIME_MAX function itself was added in v5.0.16).